61 results
Search Results
2. Performances of two rapid LAMP-based techniques for the intrapartum detection of Group B Streptococcus vaginal colonization
- Author
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Charfi, Rym, Guyonnet, Cécile, Untrau, Meiggie, Giacometti, Gaëlle, Paper, Thierry, Poyart, Claire, Plainvert, Céline, and Tazi, Asmaa
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- 2024
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3. Bioorthogonal click chemistry for fluorescence imaging of choline phospholipids in plants
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Paper, Janet M., Mukherjee, Thiya, and Schrick, Kathrin
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- 2018
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4. Novel microwave assisted carboxymethyl-graphene oxide and its hepatoprotective activity.
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Tohamy HS, Mohamed FES, and El-Sakhawy M
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- Animals, Male, Protective Agents pharmacology, Protective Agents chemistry, Protective Agents therapeutic use, Uric Acid, Alanine Transaminase blood, Aspartate Aminotransferases blood, Urea analogs & derivatives, Urea pharmacology, Mice, Graphite chemistry, Microwaves, Chemical and Drug Induced Liver Injury prevention & control, Liver drug effects, Liver pathology, Liver metabolism, Carbon Tetrachloride toxicity
- Abstract
This study reports a novel, eco-friendly; fast and cost-effective microwave method for synthesizing carboxymethylated graphene oxide (CMGO) from sugarcane residues. Fourier-transform infrared spectroscopy (FTIR) confirmed successful CMGO synthesis through the presence of characteristic peaks at 1567.93 and 1639.29 cm
-1 (COONa vibrations) and increased CH2 intensity compared to unmodified graphene oxide (GO). Furthermore, CMGO derived from sugarcane residues demonstrated potential in mitigating the side effects of toxic materials like carbon tetrachloride (CCl4 ). Treatment with CMGO partially reduced elevated levels of liver enzymes (ALT and AST) and nitrogenous waste products (urea and uric acid) in CCl4 -induced liver damage models, suggesting an improvement in liver function despite ongoing cellular damage.This work paves the way for a sustainable and economical approach to produce functionalized graphene oxide with promising biomedical applications in alleviating toxin-induced liver injury., (© 2024. The Author(s).)- Published
- 2024
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5. Macrophages modulate fibrosis during newt lens regeneration.
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Tsissios G, Sallese A, Perez-Estrada JR, Tangeman JA, Chen W, Smucker B, Ratvasky SC, Grajales-Esquivel E, Martinez A, Visser KJ, Joven Araus A, Wang H, Simon A, Yun MH, and Del Rio-Tsonis K
- Subjects
- Animals, Apoptosis drug effects, Cell Proliferation drug effects, Macrophages metabolism, Regeneration drug effects, Fibrosis, Lens, Crystalline metabolism, Lens, Crystalline cytology, Lens, Crystalline injuries, Salamandridae
- Abstract
Background: Previous studies have suggested that macrophages are present during lens regeneration in newts, but their role in the process is yet to be elucidated., Methods: Here we generated a transgenic reporter line using the newt, Pleurodeles waltl, that traces macrophages during lens regeneration. Furthermore, we assessed early changes in gene expression during lens regeneration using two newt species, Notophthalmus viridescens and Pleurodeles waltl. Finally, we used clodronate liposomes to deplete macrophages during lens regeneration in both species and tested the effect of a subsequent secondary injury after macrophage recovery., Results: Macrophage depletion abrogated lens regeneration, induced the formation of scar-like tissue, led to inflammation, decreased iris pigment epithelial cell (iPEC) proliferation, and increased rates of apoptosis in the eye. Some of these phenotypes persisted throughout the last observation period of 100 days and could be attenuated by exogenous FGF2 administration. A distinct transcript profile encoding acute inflammatory effectors was established for the dorsal iris. Reinjury of the newt eye alleviated the effects of macrophage depletion, including the resolution of scar-like tissue, and re-initiated the regeneration process., Conclusions: Together, our findings highlight the importance of macrophages for facilitating a pro-regenerative environment in the newt eye by regulating fibrotic responses, modulating the overall inflammatory landscape, and maintaining the proper balance of early proliferation and late apoptosis of the iPECs., (© 2024. The Author(s).)
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- 2024
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6. Green ecofriendly enhancement of cellulase productivity using agricultural wastes by Aspergillus terreus MN901491: statistical designs and detergent ability on cotton fabrics.
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Abdella MAA, Ahmed NE, and Hasanin MS
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- Detergents, Aspergillus, Research Design, Cellulase, Oryza
- Abstract
Background: Cellulase is considered a group member of the hydrolytic enzymes, responsible for catalyzing the hydrolysis of cellulose and has various industrial applications. Agricultural wastes are used as an inexpensive source for several utilizable products throughout the world. So, searching for cellulase enzymes from fungal strains capable of utilizing agricultural wastes to increase productivity, reduce costs and overcome waste accumulation in the environment is very important to evaluate its potency as a bio-additive to detergent agents., Results: In the current study, the previously identified fungal strain Aspergillus terreus MN901491 was screened and selected for cellulase production. Medium parameters were optimized using one-factor-at-a-time (OFAT) and multi-factorial (Plackett-Burman and Box-Behnken) design methods. OFAT showed the ability of the fungal strain to utilize agricultural wastes (corn cob and rice straw) as a substrate. Also, yeast extract was the best nitrogen source for enhancing cellulase productivity. The most significant variables were determined by Plackett-Burman Design (PBD) and their concentrations were optimized by Response Surface Methodology (RSM) using Box-Behnken Design (BBD). Among eleven independent variables screened by PBD, malt extract, (NH
4 )2 SO4 , and KCl were the most significant ones followed by rice straw which affected cellulase production positively. The ANOVA results particularly the R2 -value of PBD (0.9879) and BBD (0.9883) confirmed the model efficiency and provided a good interpretation of the experiments. PBD and BBD improved cellulase productivity by 6.1-fold greater than that obtained from OFAT. Medium optimization using OFAT and statistical models increased cellulase production from A. terreus MN901491 by 9.3-fold compared to the non-optimized medium. Moreover, the efficiency of cellulase activity on cotton fabrics as a bio-additive detergent was evaluated and estimated using whiteness and scanning electron microscope (SEM) that affirmed its potential effect and remarkable detergent ability to improve whiteness by 200% in comparison with non-washed fabric and by 190% in comparison with fabric washed by water., Conclusion: The presented work was stabilized as a multi-efficiency in which wastes were used to produce cellulase enzyme from the fungal strain, Aspergillus terreus MN901491 as a bio-additive to detergent applications that involved ecofriendly and green processes., (© 2024. The Author(s).)- Published
- 2024
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7. Engineering Saccharomyces cerevisiae for targeted hydrolysis and fermentation of glucuronoxylan through CRISPR/Cas9 genome editing.
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Ravn JL, Manfrão-Netto JHC, Schaubeder JB, Torello Pianale L, Spirk S, Ciklic IF, and Geijer C
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- Fermentation, Hydrolysis, CRISPR-Cas Systems, Ethanol metabolism, Polymers metabolism, Glucuronidase, Xylose metabolism, Saccharomyces cerevisiae metabolism, Gene Editing, Xylans
- Abstract
Background: The abundance of glucuronoxylan (GX) in agricultural and forestry residual side streams positions it as a promising feedstock for microbial conversion into valuable compounds. By engineering strains of the widely employed cell factory Saccharomyces cerevisiae with the ability to directly hydrolyze and ferment GX polymers, we can avoid the need for harsh chemical pretreatments and costly enzymatic hydrolysis steps prior to fermentation. However, for an economically viable bioproduction process, the engineered strains must efficiently express and secrete enzymes that act in synergy to hydrolyze the targeted polymers., Results: The aim of this study was to equip the xylose-fermenting S. cerevisiae strain CEN.PK XXX with xylanolytic enzymes targeting beechwood GX. Using a targeted enzyme approach, we matched hydrolytic enzyme activities to the chemical features of the GX substrate and determined that besides endo-1,4-β-xylanase and β-xylosidase activities, α-methyl-glucuronidase activity was of great importance for GX hydrolysis and yeast growth. We also created a library of strains expressing different combinations of enzymes, and screened for yeast strains that could express and secrete the enzymes and metabolize the GX hydrolysis products efficiently. While strains engineered with BmXyn11A xylanase and XylA β-xylosidase could grow relatively well in beechwood GX, strains further engineered with Agu115 α-methyl-glucuronidase did not display an additional growth benefit, likely due to inefficient expression and secretion of this enzyme. Co-cultures of strains expressing complementary enzymes as well as external enzyme supplementation boosted yeast growth and ethanol fermentation of GX, and ethanol titers reached a maximum of 1.33 g L
- 1 after 48 h under oxygen limited condition in bioreactor fermentations., Conclusion: This work underscored the importance of identifying an optimal enzyme combination for successful engineering of S. cerevisiae strains that can hydrolyze and assimilate GX. The enzymes must exhibit high and balanced activities, be compatible with the yeast's expression and secretion system, and the nature of the hydrolysis products must be such that they can be taken up and metabolized by the yeast. The engineered strains, particularly when co-cultivated, display robust growth and fermentation of GX, and represent a significant step forward towards a sustainable and cost-effective bioprocessing of GX-rich biomass. They also provide valuable insights for future strain and process development targets., (© 2024. The Author(s).)- Published
- 2024
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8. Unveiling the silver lining: examining the effects of biogenic silver nanoparticles on the growth dynamics of in vitro olive shoots.
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Hasanin MS, Hassan SAM, AbdAllatif AM, and Darwesh OM
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- Silver pharmacology, Plant Extracts chemistry, Plant Extracts pharmacology, Olea, Metal Nanoparticles chemistry
- Abstract
The current study aimed to evaluate the effects of biogenic silver nanoparticles (AgNPs) on growth behavior and leaf anatomy of in vitro growing shoots of 'Picual' and 'Dolce' olive cultivars. Biosynthesis of AgNPs was carried out using the cell-free filtrate of Fusarium oxysporum. The dimension and shape of the synthesized AgNPs have been analyzed using spectroscopy and topography analysis tools, confirming that the biosynthesis of AgNPs is a crystalline nanostructure with an average particle size of 37 nm. The shoots of the selected olive cultivars were cultured on Rugini olive medium-supplemented AgNPs at 0, 10, 20, and 30mg L
- 1 . The effect of genotypes on shoot multiplication was significant, 'Picual' recorded higher values of shoot growth parameters compared with 'Dolce' cultivar. Adding AgNPs to the culture medium significantly affected the growth of in vitro olive shoots. AgNPs at 20 and 30mg L- 1 produced higher values of the number of shoots, shoot length, and leaf number of Picual cv. compared with the control treatments, but the higher AgNPs concentration harmed the growth parameters of Dolce cv. and recorded lower growth values compared with the lower concentration (10mg L- 1 ). AgNPs had a significant effect on leaf morphology and their anatomical structure. The current results showed that the stimulatory effect of AgNPs on shoot growth of in vitro olive shoots is highly dependent on plant genotype and nanoparticle concentration., (© 2024. The Author(s).)- Published
- 2024
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9. Altered neurophysiological responses during empathy for pain in insomnia: evidence from an EEG study in non-clinical samples.
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Li S, He M, Lin L, Chen Q, Ru T, and Zhou G
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- Humans, Empathy, Electroencephalography, Pain, Evoked Potentials physiology, Sleep Initiation and Maintenance Disorders
- Abstract
Background: This study aims to investigate the behavioral and neurophysiological changes accompanying the empathy for pain among individuals with insomnia in nonclinical samples, which has been scarcely explored in the existing literature despite the deleterious effects of sleep disturbance on social behavior, and interactions had been well-documented., Methods: Twenty-one individuals with insomnia in nonclinical samples and 20 healthy individuals as normal controls participated in the study. Electroencephalograph (EEG) was continuously recorded, while the participants underwent an empathy for pain task., Results: Subjective ratings of pain for painful and non-painful images revealed no statistically significant differences between the insomnia and control groups. The painful images induced a smaller P2 compared to non-painful images in the insomnia group, whereas no such difference was revealed for the controls. Moreover, a higher power density of the alpha and theta2 bands in the posterior brain regions was found in the insomnia group compared to the control group., Conclusion: These findings suggest that individuals with insomnia exhibit altered neurophysiological responses to pain stimuli and a lower capacity to share empathy for pain. These alterations may be associated with changes in attentional mechanisms., (© 2024. The Author(s).)
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- 2024
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10. The early negative bias of social semantics: evidence from behavioral and ERP studies.
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Fan X, Xu Q, Liu J, Xing H, Ning L, Chen Q, and Yang Y
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- Male, Humans, Female, Evoked Potentials, Brain, Existentialism, Semantics, Electroencephalography
- Abstract
Background: Compared to nonsocial information, the human brain is more highly sensitive to social information. As a kind of typical social semantic information, the words describing person traits differ from the nonsocial semantic information describing inanimate objects in many ways. It remains to be seen whether the processing of trait words has a valence asymmetric and whether it differs from the processing of nonsocial semantic information in terms of behavioral responses and neural temporal processes., Method: Taking person and object names as priming stimuli and adjective words only used for describing humans or objects as target stimuli, the present study aimed to investigate the processing characteristics of social and nonsocial semantic information by recording both behavioral and ERP data., Results: Behavioral results showed that the response times for negative words were significantly slower than those for positive words whether for social or nonsocial semantic information. The accuracy rates of negative words were significantly lower than those of positive words when the targets were social words which is contrary to the nonsocial words. The ERP results indicated that there was a negative bias effect on the processing of both types of information during the whole time course of brain neural activity; that is, the P2, N400, and LPP amplitudes elicited by negative words were larger than those elicited by positive words; However, the negative bias effect of social semantic information started at the early perceptual stage which was significantly earlier than the onset of negative bias of nonsocial semantic information, and was significantly affected by the prime type. In addition, there was a significant semantic conflict N400 effect only for nonsocial semantic information., Conclusions: Overall, the present study revealed the existence of an early negative bias of social information and provided evidence for the specificity of social information., (© 2023. BioMed Central Ltd., part of Springer Nature.)
- Published
- 2023
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11. Valorization of Boehmeria nivea stalk towards multipurpose fractionation: furfural, pulp, and phenolic monomers.
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Zhang Z, Tao F, and Ji H
- Abstract
Background: As one of the most abundant bioresource in nature, the value-added utilization of lignocellulosic biomass is limited due to its inherent stubbornness. Pretreatment is a necessary step to break down the recalcitrance of cell walls and achieve an efficient separation of three main components (cellulose, hemicelluloses, and lignin)., Results: In this study, hemicelluloses and lignin in Boehmeria nivea stalks were selectively extracted with a recyclable acid hydrotrope, an aqueous solution of P-toluenesulfonic acid (p-TsOH). 79.86% of hemicelluloses and 90.24% of lignin were removed under a mild pretreatment condition, C80T80t20, (acid concentration of 80 wt%, pretreatment temperature and time of 80 °C and 20 min, respectively). After ultrasonic treatment for 10 s, the residual cellulose-rich solid was directly converted into pulp. Subsequently, the latter was utilized to produce paper via mixing with softwood pulp. The prepared handsheets with a pulp addition of 15 wt% displayed higher tear strength (8.31 mN m
2 /g) and tensile strength (8.03 Nm/g) than that of pure softwood pulp. What's more, the hydrolysates of hemicelluloses and the extracted lignin were transformed to furfural and phenolic monomers with yields of 54.67% and 65.3%, respectively., Conclusions: The lignocellulosic biomass, Boehmeria nivea stalks, were valorized to pulp, furfural, and phenolic monomers, successfully. And a potential solution of comprehensive utilization of Boehmeria nivea stalks was provided in this paper., (© 2023. The Author(s).)- Published
- 2023
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12. Sustainable bacterial cellulose production by Achromobacter using mango peel waste.
- Author
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Hasanin MS, Abdelraof M, Hashem AH, and El Saied H
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- Biopolymers, Culture Media chemistry, Cellulose, Mangifera
- Abstract
Bacterial Cellulose (BC) is still the most renewable available biopolymer produced in fine nature from alternative microbial sources as bacteria. In the present study, newly BC producing bacteria were successfully isolated from acidic fruits. The most potent producer was isolated from strawberry and identified genetically using 16 s rRNA technique as Achromobacter S3. Different fruit peels were screened to produce BC using the cheapest culture medium. Among them, Mango peel waste (MPW) hydrolysate proved to be the significant inducible alternative medium without any extra nutrients for the maximum productivity. Improvement of the BC yield was successfully achieved via statistical optimization of the MPW culture medium, from 0.52 g/L to 1.22 g/L with 2.5-fold increased about the standard HS culture medium. Additionally, the physicochemical analysis affirmed the cellulose molecular structure as well as observed the crystallinity of nanofiber as 72 and 79% for BC produced by Achromobacter S33 on HS and MPW media, respectively. Moreover, the topographical study illustrated that the BC nanofibers had close characteristics upon fiber dimeter and length as about 10 and 200 nm, respectively., (© 2023. The Author(s).)
- Published
- 2023
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13. Fucoidan-derived carbon dots against Enterococcus faecalis biofilm and infected dentinal tubules for the treatment of persistent endodontic infections.
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Tang S, Zhang H, Mei L, Dou K, Jiang Y, Sun Z, Wang S, Hasanin MS, Deng J, and Zhou Q
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- Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents therapeutic use, Biofilms, Carbon, Polysaccharides, Sodium Hypochlorite pharmacology, Sodium Hypochlorite therapeutic use, Enterococcus faecalis, Root Canal Irrigants pharmacology, Root Canal Irrigants therapeutic use
- Abstract
Enterococcus faecalis (E. faecalis) biofilm-associated persistent endodontic infections (PEIs) are one of the most common tooth lesions, causing chronic periapical periodontitis, root resorption, and even tooth loss. Clinical root canal disinfectants have the risk of damaging soft tissues (e.g., mucosa and tongue) and teeth in the oral cavity, unsatisfactory to the therapy of PEIs. Nanomaterials with remarkable antibacterial properties and good biocompatibility have been developed as a promising strategy for removing pathogenic bacteria and related biofilm. Herein, carbon dots (CDs) derived from fucoidan (FD) are prepared through a one-pot hydrothermal method for the treatment of PEIs. The prepared FDCDs (7.15 nm) with sulfate groups and fluorescence property are well dispersed and stable in water. Further, it is found that in vitro FDCDs display excellent inhibiting effects on E. faecalis and its biofilm by inducing the formation of intracellular and extracellular reactive oxygen species and altering bacterial permeability. Importantly, the FDCDs penetrated the root canals and dentinal tubules, removing located E. faecalis biofilm. Moreover, the cellular assays show that the developed FDCDs have satisfactory cytocompatibility and promote macrophage recruitment. Thus, the developed FDCDs hold great potential for the management of PEIs., (© 2022. The Author(s).)
- Published
- 2022
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14. Cell membrane-camouflaged inorganic nanoparticles for cancer therapy.
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Song W, Jia P, Zhang T, Dou K, Liu L, Ren Y, Liu F, Xue J, Hasanin MS, Qi H, and Zhou Q
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- Cell Membrane, Humans, Phototherapy methods, Hyperthermia, Induced methods, Nanoparticles therapeutic use, Neoplasms drug therapy, Neoplasms pathology, Photochemotherapy
- Abstract
Inorganic nanoparticles (INPs) have been paid great attention in the field of oncology in recent past years since they have enormous potential in drug delivery, gene delivery, photodynamic therapy (PDT), photothermal therapy (PTT), bio-imaging, driven motion, etc. To overcome the innate limitations of the conventional INPs, such as fast elimination by the immune system, low accumulation in tumor sites, and severe toxicity to the organism, great efforts have recently been made to modify naked INPs, facilitating their clinical application. Taking inspiration from nature, considerable researchers have exploited cell membrane-camouflaged INPs (CMCINPs) by coating various cell membranes onto INPs. CMCINPs naturally inherit the surface adhesive molecules, receptors, and functional proteins from the original cell membrane, making them versatile as the natural cells. In order to give a timely and representative review on this rapidly developing research subject, we highlighted recent advances in CMCINPs with superior unique merits of various INPs and natural cell membranes for cancer therapy applications. The opportunity and obstacles of CMCINPs for clinical translation were also discussed. The review is expected to assist researchers in better eliciting the effect of CMCINPs for the management of tumors and may catalyze breakthroughs in this area., (© 2022. The Author(s).)
- Published
- 2022
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15. Co-production of amino acid-rich xylooligosaccharide and single-cell protein from paper mulberry by autohydrolysis and fermentation technologies.
- Author
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Gu Y, Hu Y, Huang C, Lai C, Ling Z, and Yong Q
- Abstract
Background: Autohydrolysis is an extensively investigated pretreatment method due to its environmental friendliness. During autohydrolysis, most xylan from hemicellulose can be converted into xylooligosaccharides (XOS), and cellulose in the autohydrolyzed residues can be transformed into glucose after enzymatic hydrolysis. Both of these are value-added biochemicals in the biorefining process. In this work, paper mulberry (PM), which contains abundant protein, was utilized as a raw material to coproduce XOS and single-cell protein (SCP) through autohydrolysis and fermentation technologies., Results: The results showed that 8.3 g of XOS and 1.8 g of amino acids could be recovered in the autohydrolysate (based on 100 g raw material) after autohydrolysis (170 °C, 1 h). Moreover, 5.7 g of low-DP XOS along with 1.8 g of amino acids could be further obtained from the autohydrolysate after hydrolysis with endo-β-1-4-xylanase. In addition, 20.1 g of fermentable monosaccharides was recovered after hydrolyzing the autohydrolyzed PM with cellulase, which can be used to produce 4.8 g of SCP after fermentation with Candida utilis., Conclusion: As a valuable application of PM, a novel process is proposed to coproduce amino acid-rich XOS and SCP through autohydrolysis. The carbohydrate of PM is effectively converted to high value-added products., (© 2022. The Author(s).)
- Published
- 2022
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16. THF co-solvent pretreatment prevents lignin redeposition from interfering with enzymes yielding prolonged cellulase activity.
- Author
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Patri AS, Mohan R, Pu Y, Yoo CG, Ragauskas AJ, Kumar R, Kisailus D, Cai CM, and Wyman CE
- Abstract
Background: Conventional aqueous dilute sulfuric acid (DSA) pretreatment of lignocellulosic biomass facilitates hemicellulose solubilization and can improve subsequent enzymatic digestibility of cellulose to fermentable glucose. However, much of the lignin after DSA pretreatment either remains intact within the cell wall or readily redeposits back onto the biomass surface. This redeposited lignin has been shown to reduce enzyme activity and contribute to rapid enzyme deactivation, thus, necessitating significantly higher enzyme loadings than deemed economical for biofuel production from biomass., Results: In this study, we demonstrate how detrimental lignin redeposition on biomass surface after pretreatment can be prevented by employing Co-solvent Enhanced Lignocellulosic Fractionation (CELF) pretreatment that uses THF-water co-solvents with dilute sulfuric acid to solubilize lignin and overcome limitations of DSA pretreatment. We first find that enzymatic hydrolysis of CELF-pretreated switchgrass can sustain a high enzyme activity over incubation periods as long as 5 weeks with enzyme doses as low as 2 mg protein/g glucan to achieve 90% yield to glucose. A modified Ninhydrin-based protein assay revealed that the free-enzyme concentration in the hydrolysate liquor, related to enzyme activity, remained unchanged over long hydrolysis times. DSA-pretreated switchgrass, by contrast, had a 40% drop in free enzymes in solution during incubation, providing evidence of enzyme deactivation. Furthermore, measurements of enzyme adsorption per gram of lignin suggested that CELF prevented lignin redeposition onto the biomass surface, and the little lignin left in the solids was mostly integral to the original lignin-carbohydrate complex (LCC). Scanning electron micrographs and NMR characterization of lignin supported this observation., Conclusions: Enzymatic hydrolysis of solids from CELF pretreatment of switchgrass at low enzyme loadings was sustained for considerably longer times and reached higher conversions than for DSA solids. Analysis of solids following pretreatment and enzymatic hydrolysis showed that prolonged cellulase activity could be attributed to the limited lignin redeposition on the biomass surface making more enzymes available for hydrolysis of more accessible glucan.
- Published
- 2021
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17. Life cycle greenhouse gas emissions of ethanol produced via fermentation of sugars derived from shrub willow (Salix ssp.) hot water extraction in the Northeast United States.
- Author
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Therasme O, Volk TA, Eisenbies MH, Amidon TE, and Fortier MO
- Abstract
Background: The amount of carbon dioxide in the atmosphere has been on the rise for more than a century. Bioenergy crops are seen by the Intergovernmental Panel on Climate Change as an essential part of the solution to addressing climate change. To understand the potential impact of shrub willow (Salix spp.) crop in the northeast United States, effective and transparent life cycle assessment of these systems needs to occur., Results: Here we show, ethanol produced from the fermentation of sugars from hot water extract of willow grown on cropland can sequester 0.012 ± 0.003 kg CO
2eq MJ-1 for a supply system incorporating summer harvest and storage. Despite decreases in soil organic carbon when willow is instead grown on grassland, the produced fuel still can provide significant climate benefits compared to gasoline., Conclusions: Shrub willow converted to ethanol can be a carbon negative source of transportation fuel when the electricity and heat required for the conversion process are generated from renewable biomass. The sequestration of carbon in the belowground portion of the plants is essential for the negative GHG balance for cropland and low GHG emissions in grassland.- Published
- 2021
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18. Effect of residual extractable lignin on acetone-butanol-ethanol production in SHF and SSF processes.
- Author
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Li J, Zhang Y, Shi S, and Tu M
- Abstract
Background: Lignin plays an important role in biochemical conversion of biomass to biofuels. A significant amount of lignin is precipitated on the surface of pretreated substrates after organosolv pretreatment. The effect of this residual lignin on enzymatic hydrolysis has been well understood, however, their effect on subsequent ABE fermentation is still unknown., Results: To determine the effect of residual extractable lignin on acetone-butanol-ethanol (ABE) fermentation in separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes, we compared ABE production from ethanol-washed and unwashed substrates. The ethanol organosolv pretreated loblolly pine (OPLP) was used as the substrate. It was observed that butanol production from OPLP-UW (unwashed) and OPLP-W (washed) reached 8.16 and 1.69 g/L, respectively, in SHF. The results showed that ABE production in SHF from OPLP-UW prevents an "acid crash" as compared the OPLP-W. In SSF process, the "acid crash" occurred for both OPLP-W and OPLP-UW. The inhibitory extractable lignin intensified the "acid crash" for OPLP-UW and resulted in less ABE production than OPLP-W. The addition of detoxified prehydrolysates in SSF processes shortened the fermentation time and could potentially prevent the "acid crash"., Conclusions: The results suggested that the residual extractable lignin in high sugar concentration could help ABE production by lowering the metabolic rate and preventing "acid crash" in SHF processes. However, it became unfavorable in SSF due to its inhibition of both enzymatic hydrolysis and ABE fermentation with low initial sugar concentration. It is essential to remove extractable lignin of substrates for ABE production in SSF processes. Also, a higher initial sugar concentration is needed to prevent the "acid crash" in SSF processes., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)
- Published
- 2020
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19. Exploring why sodium lignosulfonate influenced enzymatic hydrolysis efficiency of cellulose from the perspective of substrate-enzyme adsorption.
- Author
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Zheng W, Lan T, Li H, Yue G, and Zhou H
- Abstract
Background: Cellulase adsorbed on cellulose is productive and helpful to produce reducing sugars in enzymatic hydrolysis of lignocellulose; however, cellulase adsorbed on lignin is non-productive. Increasing productive adsorption of cellulase on cellulose would be beneficial in improving enzymatic hydrolysis. Adding lignin that was more hydrophilic in hydrolysis system could increase productive adsorption and promote hydrolysis. However, the effect mechanism is still worth exploring further. In this study, lignosulfonate (LS), a type of hydrophilic lignin, was used to study its effect on cellulosic hydrolysis., Results: The effect of LS on the enzymatic hydrolysis of pure cellulose (Avicel) and lignocellulose [dilute acid (DA) treated sugarcane bagasse (SCB)] was investigated by analyzing enzymatic hydrolysis efficiency, productive and non-productive cellulase adsorptions, zeta potential and particle size distribution of substrates. The result showed that after adding LS, the productive cellulase adsorption on Avicel reduced. Adding LS to Avicel suspension could form the Avicel-LS complexes. The particles were charged more negatively and the average particle size was smaller than Avicel before adding LS. In addition, adding LS to cellulase solution formed the LS-cellulase complexes. For DA-SCB, adding LS decreased the non-productive cellulase adsorption on DA-SCB from 3.92 to 2.99 mg/g lignin and increased the productive adsorption of cellulase on DA-SCB from 2.00 to 3.44 mg/g cellulose. Besides, the addition of LS promoted the formation of LS-lignin complexes and LS-cellulase complexes, and the complexes had more negative charges and smaller average sizes than DA-SCB lignin and cellulase particles before adding LS., Conclusions: In this study, LS inhibited Avicel's hydrolysis, but enhanced DA-SCB's hydrolysis. This stemmed from the fact that LS could bind cellulase and Avicel, and occupied the binding sites of cellulase and Avicel. Thus, a decreased productive adsorption of cellulase on Avicel arose. Regarding DA-SCB, adding LS, which enhanced hydrolysis efficiency of DA-SCB, increased the electrostatic repulsion between DA-SCB lignin and cellulase, and therefore, decreased non-productive adsorption of cellulase on DA-SCB lignin and enhanced productive adsorption of cellulase on DA-SCB cellulose., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)
- Published
- 2020
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20. Total utilization of lignin and carbohydrates in Eucalyptus grandis : an integrated biorefinery strategy towards phenolics, levulinic acid, and furfural.
- Author
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Chen X, Zhang K, Xiao LP, Sun RC, and Song G
- Abstract
Background: Lignocellulosic biomass, which is composed of cellulose, hemicellulose and lignin, represents the most abundant renewable carbon source with significant potential for the production of sustainable chemicals and fuels. Current biorefineries focus on cellulose and hemicellulose valorization, whereas lignin is treated as a waste product and is burned to supply energy to the biorefineries. The depolymerization of lignin into well-defined mono-aromatic chemicals suitable for downstream processing is recognized increasingly as an important starting point for lignin valorization. In this study, conversion of all three components of Eucalyptus grandis into the corresponding monomeric chemicals was investigated using solid and acidic catalyst in sequence., Results: Lignin was depolymerized into well-defined monomeric phenols in the first step using a Pd/C catalyst. The maximum phenolic monomers yield of 49.8 wt% was achieved at 240 °C for 4 h under 30 atm H
2 . In the monomers, 4-propanol guaiacol (12.9 wt%) and 4-propanol syringol (31.9 wt%) were identified as the two major phenolic products with 90% selectivity. High retention of cellulose and hemicellulose pulp was also obtained, which was treated with FeCl3 catalyst to attain 5-hydroxymethylfurfural, levulinic acid and furfural simultaneously. The optimal reaction condition for the co-conversion of hemicellulose and cellulose was established as 190 °C and 100 min, from which furfural and levulinic acid were obtained in 55.9% and 73.6% yields, respectively. Ultimately, 54% of Eucalyptus sawdust can be converted into well-defined chemicals under such an integrated biorefinery method., Conclusions: A two-step process (reductive catalytic fractionation followed by FeCl3 catalysis) allows the fractionation of all the three biopolymers (cellulose, hemicellulose, and lignin) in Eucalyptus biomass, which provides a promising strategy to make high-value chemicals from sustainable biomass., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)- Published
- 2020
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21. Improvement of corn stover fuel properties via hydrothermal carbonization combined with surfactant.
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Tu R, Sun Y, Wu Y, Fan X, Wang J, Cheng S, Jia Z, Jiang E, and Xu X
- Abstract
Background: Biomass fuel has been used to supply heat or crude materials in industry to replace the traditional fossil fuel which was one of the chief causes of climate warming. However, the large-scale utilization of biomass fuel was restricted due to the low density and high hydrophilicity of biomass, which causes the problem of transportation and storage. Therefore, pelletization of biomass was used to improve its fuel density. At present, the biomass pellet was widely used to supply heat, gas or electricity generation via gasification, which supplied clean and sustainable energy for industry. However, the energy consumption during pelletization and high hydrophilicity of pellets were still the problem for the large-scale application of biomass pellet. In this study, hydrothermal carbonization and surfactant played the role of permeation, adsorption and wetting in the solution, which was expected to improve the fuel properties and pelletization effectivity of corn stover., Results: In the article, surfactant (PEG400, Span80, SDBS) was chosen to be combined with wet torrefaction to overcome the drawbacks and improve the pelletization and combustion properties of Corn stover (CS). Especially, hydrothermal carbonization (HTC) combined with surfactant improves the yield of solid products and reduces the ash content of solid product, which was beneficial for reducing the ashes of furnace during gasification. Meanwhile, surfactant promotes the formation of pseudo-lignin and the absorption for oil with low O and high C during HTC, which improves the energy density of solid product. Furthermore, the oil in solid product plays the role of lubricant and binder, which reduces the negative effect of high energy consumption, low bulk density and weak pellets strength caused by HTC during pelletization. HTC combined with surfactant improved the hydrophobicity of pellet as well as grindability due to the modification of solid product. Moreover, surfactant combined with HTC improved the combustion characteristic of solid product such as ignition and burning temperature as well as kinetic parameters due to the bio-oil absorbed and the improvement of surface and porosity., Conclusions: The study supplied a new, less-energy intensive and effective method to improve the pelletization and combustion properties of corn stover via hydrothermal carbonization combined with surfactant, and provided a promising alternative fuel from corn stover ., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2019.)
- Published
- 2019
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22. Engineered Thermoanaerobacterium aotearoense with nfnAB knockout for improved hydrogen production from lignocellulose hydrolysates.
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Li Y, Hu J, Qu C, Chen L, Guo X, Fu H, and Wang J
- Abstract
Background: As a renewable and clean energy carrier, the production of biohydrogen from low-value feedstock such as lignocellulose has increasingly garnered interest. The NADH-dependent reduced ferredoxin:NADP
+ oxidoreductase (NfnAB) complex catalyzes electron transfer between reduced ferredoxin and NAD(P)+ , which is critical for production of NAD(P)H-dependent products such as hydrogen and ethanol. In this study, the effects on end-product formation of deletion of nfnAB from Thermoanaerobacterium aotearoense SCUT27 were investigated., Results: Compared with the parental strain, the NADH/NAD+ ratio in the ∆nfnAB mutant was increased. The concentration of hydrogen and ethanol produced increased by (41.1 ± 2.37)% ( p < 0.01) and (13.24 ± 1.12)% ( p < 0.01), respectively, while the lactic acid concentration decreased by (11.88 ± 0.96)% ( p < 0.01) when the ∆nfnAB mutant used glucose as sole carbon source. No obvious inhibition effect was observed for either SCUT27 or SCUT27/ ∆nfnAB when six types of lignocellulose hydrolysate pretreated with dilute acid were used for hydrogen production. Notably, the SCUT27/ ∆nfnAB mutant produced 190.63-209.31 mmol/L hydrogen, with a yield of 1.66-1.77 mol/mol and productivity of 12.71-13.95 mmol/L h from nonsterilized rice straw and corn cob hydrolysates pretreated with dilute acid., Conclusions: The T. aotearoense SCUT27/ ∆nfnAB mutant showed higher hydrogen yield and productivity compared with those of the parental strain. Hence, we demonstrate that deletion of nfnAB from T. aotearoense SCUT27 is an effective approach to improve hydrogen production by redirecting the electron flux, and SCUT27/ ∆nfnAB is a promising candidate strain for efficient biohydrogen production from lignocellulosic hydrolysates., Competing Interests: Competing interestsThe authors declare that they have no competing interests.- Published
- 2019
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23. A study of reproducibility of kinesiology tape applications: review, reliability and validity.
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Selva F, Pardo A, Aguado X, Montava I, Gil-Santos L, and Barrios C
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- Equipment Design methods, Humans, Kinesiology, Applied methods, Proprioception, Reproducibility of Results, Athletic Tape standards, Equipment Design standards, Kinesiology, Applied standards, Muscle Strength Dynamometer standards
- Abstract
Background: Literature addressing the mechanical properties of kinesiology tape is quite scarce. There are no studies which focus on the mechanical characteristics of kinesiology tape, its mechanical properties, nor its adherence following the ISO international standard test methods for tape elongation., Methods: This study quantified the mechanical characteristics of 380 samples of kinesiology tape from 19 different brands and in 4 different colors using a dynamometer. Mechanical testing was controlled by UNE EN ISO 13934-1., Results: Significant differences were found between tape brands in terms of grammage, maximum force tenacity, work, pre-elongation and percentage elongation (P < .001). Regarding kinesiology tape color, statistically significant differences were found between tape brands in terms of grammage, maximum force and tenacity (P < .001), work and pre-elongation (P < .05). When adherence was studied, statistically significant differences were found between tape brands in terms of maximum force and work (P < .001)., Conclusions: The different kinesiology tapes presented different behaviors with regard to rupture and removal when applied to skin in dry state, wet state and after being submerged in artificial acidic sweat solution. Therefore, different kinesiology tape brands will produce different levels of strain even though the same elongation is used. Depending on the characteristics (body dimensions) and properties (skin elongation) of each subject in the sample, bandages with different elongations must be applied to achieve the same strain in all of the tapes and therefore produce the same effect. The absence of these data at this time limits the reliability of previous clinical studies, makes comparing their findings impossible and presents new challenges for research in this field.
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- 2019
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24. Identification of functional butanol-tolerant genes from Escherichia coli mutants derived from error-prone PCR-based whole-genome shuffling.
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He X, Xue T, Ma Y, Zhang J, Wang Z, Hong J, Hui L, Qiao J, Song H, and Zhang M
- Abstract
Background: Butanol is an important biofuel and chemical. The development of butanol-tolerant strains and the identification of functional butanol-tolerant genes is essential for high-yield bio-butanol production due to the toxicity of butanol., Results: Escherichia coli BW25113 was subjected for the first time to error-prone PCR-based whole-genome shuffling. The resulting mutants BW1847 and BW1857 were found to tolerate 2% (v/v) butanol and short-chain alcohols, including ethanol, isobutanol, and 1-pentanol. The mutants exhibited good stability under butanol stress, indicating that they are potential host strains for the construction of butanol pathways. BW1847 had better butanol tolerance than BW1857 under 0-0.75% (v/v) butanol stress, but showed a lower tolerance than BW1857 under 1.25-2% (v/v) butanol stress. Genome resequencing and PCR confirmation revealed that BW1847 and BW1857 had nine and seven single nucleotide polymorphisms, respectively, and a common 14-kb deletion. Functional complementation experiments of the SNPs and deleted genes demonstrated that the mutations of acrB and rob gene and the deletion of TqsA increased the tolerance of the two mutants to butanol. Genome-wide site-specific mutated strains DT385 ( acrB C
1198 T) and DT900 ( rob AT686-7 ) also showed significant tolerance to butanol and had higher butanol efflux ability than the control, further demonstrating that their mutations yield an inactive protein that enhances butanol resistance characteristics., Conclusions: Stable E. coli mutants with enhanced short alcohols and high concentrations of butanol tolerance were obtained through a rapid and effective method. The key genes of butanol tolerance in the two mutants were identified by comparative functional genomic analysis., Competing Interests: The authors declare that they have no competing interests.- Published
- 2019
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25. Smart nanoplatform for sequential drug release and enhanced chemo-thermal effect of dual drug loaded gold nanorod vesicles for cancer therapy.
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Zhu F, Tan G, Zhong Y, Jiang Y, Cai L, Yu Z, Liu S, and Ren F
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- A549 Cells, Animals, Antineoplastic Agents chemistry, Apoptosis drug effects, Cell Survival drug effects, Curcumin chemistry, Hep G2 Cells, Humans, Infrared Rays, Integrin alphaVbeta3 metabolism, KB Cells, Mice, Inbred BALB C, Paclitaxel chemistry, Particle Size, Peptides, Cyclic metabolism, Phototherapy methods, Surface Properties, Antineoplastic Agents administration & dosage, Curcumin administration & dosage, Drug Carriers chemistry, Drug Liberation, Gold chemistry, Nanotubes chemistry, Paclitaxel administration & dosage
- Abstract
Background: The combination of multiple chemotherapeutics has been used in the clinic for enhanced cancer chemotherapy, however, frequent relapse, chemo-resistance and side effects remains therapeutic hurdles. Thus, the development of co-delivery system with enhanced targeting and synergistic different modal treatments has been proposed as promising strategies for intensive improvement of the therapeutic outcomes., Results: We fabricated a nanocarrier based on gold nanorods (Au NRs), cRGD peptide-modified and multi-stimuli-responsive paclitaxel (PTX) and curcumin (CUR) release for synergistic anticancer effect and chemo-photothermal therapy (PTX/CUR/Au NRs@cRGD). The specific banding of cRGD to αvβ3 integrin receptor on the tumor cell surfaces facilitated the endocytosis of PTX/CUR/Au NRs@cRGD, and the near-infrared ray (NIR) further enhanced the drug release and chemotherapeutical efficiency. Compared to single drug, single model treatment or undecorated-PTX/CUR/Au NRs, the PTX/CUR/Au NRs@cRGD with a mild NIR showed significantly enhanced apoptosis and S phase arrest in three cancer cell lines in vitro, and improved drug accumulation in tumor sites as well as tumor growth inhibition in vivo., Conclusions: The tumor targeted chemo-photothermal therapy with the synergistic effect of dual drugs provided a versatile strategy for precise cancer therapy.
- Published
- 2019
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26. A new approach to recycle oxalic acid during lignocellulose pretreatment for xylose production.
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Cheng B, Zhang X, Lin Q, Xin F, Sun R, Wang X, and Ren J
- Abstract
Background: Dilute oxalic acid pretreatment has drawn much attention because it could selectively hydrolyse the hemicellulose fraction during lignocellulose pretreatment. However, there are few studies focusing on the recovery of oxalic acid. Here, we reported a new approach to recycle oxalic acid used in pretreatment via ethanol extraction., Results: The highest xylose content in hydrolysate was 266.70 mg xylose per 1 g corncob (85.0% yield), which was achieved using 150 mmol/L oxalic acid under the optimized treatment condition (140 °C, 2.5 h). These pretreatment conditions were employed to the subsequent pretreatment using recycled oxalic acid. Oxalic acid in the hydrolysate could be recycled according to the following steps: (1) water was removed via evaporation and vacuum drying, (2) ethanol was used to extract oxalic acid in the remaining mixture, and (3) oxalic acid and ethanol were separated by reduced pressure evaporation. The total xylose yields could be stabilized by intermittent adding oxalic acid, and the yields were in range of 46.7-64.3% in this experiment., Conclusions: This sustainable approach of recycling and reuse of oxalic acid has a significant potential application for replacing traditional dilute mineral acid pretreatment of lignocellulose, which could contribute to reduce CO
2 emissions and the cost of the pretreatment.- Published
- 2018
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27. Enhancing enzymatic saccharification of sugarcane bagasse by combinatorial pretreatment and Tween 80.
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Zhang H, Wei W, Zhang J, Huang S, and Xie J
- Abstract
Background: The recalcitrant structure of lignocellulosic biomass made it challenging for their bioconversion into biofuels and biochemicals. Pretreatment was required to deconstruct the intact structure by the removal of hemicellulose/lignin, improving the cellulose accessibility of enzyme. Combinatorial pretreatments with liquid hot water/H
2 SO4 and ethanol/NaOH of sugarcane bagasse were developed to improve enzymatic hydrolysis under mild conditions., Results: After one-step 60% ethanol containing 0.5% NaOH pretreatment with solid to liquid ratio of 1/10, the glucose yield after hydrolysis for 72 h with enzyme dosage of 20 FPU/g substrate was enhanced by 41% and 205% compared to that of NaOH or 60% ethanol pretreated solids, respectively. This improvement was correlated with the removal of hemicellulose and lignin. However, using combinatorial pretreatments with 1% H2 SO4 followed by 60% ethanol containing 0.5% NaOH, the highest glucose yield with Tween 80 reached 76%, representing 84.5% of theoretical glucose in pretreated substrate. While retaining similar glucose yield, the addition of Tween 80 capacitated either a reduction of enzyme loading by 50% or shortening hydrolysis time to 24 h. However, the enhancement with the addition of Tween 80 decreased as hydrolysis time was extended., Conclusions: This study demonstrated that a combinatorial pretreatment with 1% H2 SO4 followed by 60% ethanol containing 0.5% NaOH had significant effects on improving the enzymatic hydrolysis of sugarcane bagasse. The addition of Tween 80 enabled reducing the enzyme loading or shortening the hydrolysis time. This study provided an economically feasible and mild process for the generation of glucose, which will be subsequently converted to bioethanol and biochemicals.- Published
- 2018
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28. Biocatalytic synthesis of acylated derivatives of troxerutin: their bioavailability and antioxidant properties in vitro.
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Xin X, Zhang M, Li X, Lai F, and Zhao G
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- Anticoagulants therapeutic use, Biological Availability, Humans, Hydroxyethylrutoside chemical synthesis, Hydroxyethylrutoside therapeutic use, Anticoagulants chemical synthesis, Antioxidants metabolism, Hydroxyethylrutoside analogs & derivatives
- Abstract
Background: Flavonoid glycosides have many beneficial effects on health, but these bioactivities tend to decrease after oral administration owing to their poor lipophilicity. In this study, a facile whole-cell-based method was developed for selective preparation of monoester or diester of troxerutin, a flavonoid derivative. In addition, the bioavailabilities and antioxidant properties of troxerutin and its acylated derivatives were also investigated in cells., Results: Pseudomonas aeruginosa and Pseudomonas stutzeri cells showed high catalytic efficiency (substrate conversion > 90%) and different preferences for troxerutin, resulting in the production of its monoester (TME) and diester (TDE), respectively. The logP values of troxerutin, TME, and TDE were - 2.04 ± 0.10, - 0.75 ± 0.08, and 1.51 ± 0.05 and their P
app values were 0.34 × 10-6 ± 0.05, 0.99 × 10-6 ± 0.12, and 1.54 × 10-6 ± 0.17 cm/s, respectively. The results of hydroxyl radical, ABTS, and ORAC assays indicated that the antiradical activities of acylated derivatives did not exceed that of troxerutin, but showed higher inhibition effects upon 2,2'-azobis(2-amidinopropane) dihydrochloride-induced erythrocyte hemolysis than that of troxerutin (P < 0.05)., Conclusion: A facile and efficient whole-cell biocatalysis method was developed to synthesize troxerutin-acylated derivatives, markedly enhancing the bioavailability and antioxidant activities of troxerutin in cells. Additionally, the mechanism underlying the observed difference in the antioxidant activities of troxerutin and its esters was ascribed to both their free radical scavenging abilities and distribution on the cell membrane surface.- Published
- 2018
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29. RNA-seq analysis of lignocellulose-related genes in hybrid Eucalyptus with contrasting wood basic density.
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Nakahama K, Urata N, Shinya T, Hayashi K, Nanto K, Rosa AC, and Kawaoka A
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- Cellulose metabolism, Eucalyptus anatomy & histology, Eucalyptus enzymology, Gene Expression Profiling, Genes, Plant physiology, Lignin metabolism, Microsatellite Repeats genetics, Polymerase Chain Reaction, Sequence Analysis, RNA, Spectroscopy, Near-Infrared, Transcription Factors genetics, Xylans metabolism, Eucalyptus genetics, Genes, Plant genetics, Lignin genetics, Wood anatomy & histology
- Abstract
Background: Wood basic density (WBD), the biomass of plant cell walls per unit volume, is an important trait for elite tree selection in kraft pulp production. Here, we investigated the correlation between WBD and wood volumes or wood properties using 98 open-pollinated, 2.4 to 2.8 year-old hybrid Eucalyptus (Eucalyptus urophylla x E. grandis). Transcript levels of lignocellulose biosynthesis-related genes were studied., Results: The progeny plants had average WBD of 516 kg/m
3 with normal distribution and did not show any correlations between WBD and wood volume or components of α-cellulose, hemicellulose and Klason lignin content. Transcriptomic analysis of two groups of five plants each with high (570-609 kg/m3 ) or low (378-409 kg/m3 ) WBD was carried out by RNA-Seq analysis with total RNAs extracted from developing xylem tissues at a breast height. Lignocellulose biosynthesis-related genes, such as cellulose synthase, invertase, cinnamate-4-hydroxylase and cinnamoyl-CoA reductase showed higher transcript levels in the high WBD group. Among plant cell wall modifying genes, increased transcript levels of several expansin and xyloglucan endo-transglycosylase/hydrolase genes were also found in high WBD plants. Interestingly, strong transcript levels of several cytoskeleton genes encoding tubulin, actin and myosin were observed in high WBD plants. Furthermore, we also found elevated transcript levels of genes encoding NAC, MYB, basic helix-loop-helix, homeodomain, WRKY and LIM transcription factors in the high WBD plants. All these results indicate that the high WBD in plants has been associated with the increased transcription of many genes related to lignocellulose formation., Conclusions: Most lignocellulose biosynthesis related genes exhibited a tendency to transcribe at relatively higher level in high WBD plants. These results suggest that lignocellulose biosynthesis-related genes may be associated with WBD.- Published
- 2018
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30. A structured understanding of cellobiohydrolase I binding to poplar lignin fractions after dilute acid pretreatment.
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Yao L, Yoo CG, Meng X, Li M, Pu Y, Ragauskas AJ, and Yang H
- Abstract
Background: Cellulase adsorption to lignin is considered a cost barrier for bioethanol production; however, its detailed association mechanism is still not fully understood. In this study, two natural poplar variants with high and low sugar release performance were selected as the low and high recalcitrant raw materials (named L and H , respectively). Three different lignin fractions were extracted using ethanol, followed by p -dioxane and then cellulase treatment from the dilute acid pretreated poplar solids (fraction 1, 2, and 3, respectively)., Results: Each lignin fraction had different physicochemical properties. Ethanol-extracted lignin had the lowest weight average molecular weight, while the molecular weights for the other two lignin fractions were similar.
31 P NMR analysis revealed that lignin fraction with higher molecular weight contained more aliphatic hydroxyl groups and less phenolic hydroxyl groups. Semi-quantitative analysis by 2D HSQC NMR indicated that the lignin fractions isolated from the natural variants had different contents of syringyl (S), guaiacyl (G) and interunit linkages. Lignin extracted by ethanol contained the largest amount of S units, the smallest amounts of G and p -hydroxybenzoate (PB) subunits, while the contents of these lignin subunits in the other two lignin fractions were similar. The lignin fraction obtained after cellulase treatment was primarily comprised of β- O -4 linkages with small amounts of β-5 and β-β linkages. The binding strength of these three lignin fractions obtained by Langmuir equations were in the order of L1 > L3 > L2 for the low recalcitrance poplar and H1 > H2 > H3 for the high recalcitrance poplar., Conclusions: Overall, adsorption ability of lignin was correlated with the sugar release of poplar. Structural features of lignin were associated with its binding to CBH. For natural poplar variants, lignin fractions with lower molecular weight and polydispersity index (PDI) exhibited more CBH adsorption ability. Lignins with more phenolic hydroxyl groups had higher CBH binding strength. It was also found that lignin fractions with more condensed aromatics adsorbed more CBH likely attributed to stronger hydrophobic interactions.- Published
- 2018
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31. Efficient vitrification of mouse embryos using the Kitasato Vitrification System as a novel vitrification device.
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Momozawa K, Matsuzawa A, Tokunaga Y, Abe S, Koyanagi Y, Kurita M, Nakano M, and Miyake T
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- Animals, Blastocyst drug effects, Blastocyst physiology, Chorionic Gonadotropin administration & dosage, Female, Male, Mice, Mice, Inbred ICR, Ovulation drug effects, Ovulation physiology, Cryopreservation methods, Embryo Culture Techniques methods, Embryo Transfer methods, Vitrification
- Abstract
Background: Currently, the cryopreservation of embryos and oocytes is essential for assisted reproductive technology (ART) laboratories worldwide. This study aimed to evaluate the efficacy of the Kitasato Vitrification System (KVS) as a vitrification device for the cryopreservation of mouse embryos to determine whether this novel device can be adapted to the field of ART., Methods: In Experiment 1, blastocysts were vitrified using the KVS. Vitrified blastocysts were warmed and subsequently cultured for 72 h. In Experiment 2, 2-cell-stage embryos were vitrified using the KVS, and vitrified embryos were warmed and subsequently cultured for 96 h. In Experiment 3, we evaluated the in vivo developmental potential of vitrified 2-cell-stage embryos using the KVS, and in Experiment 4, we evaluated the cooling and warming rates for these devices using a numerical simulation., Results: In Experiment 1, there were no significant differences between the survival rates of the KVS and a control device. However, re-expanded (100%) and hatching (91.8%) rates were significantly higher for blastocysts vitrified using the KVS. In Experiment 2, there were no significant differences between the survival rates, or rates of development to the blastocyst stage, of vitrified and fresh embryos. In Experiment 3, after embryo transfer, 41% of the embryos developed into live offspring. In Experiment 4, the cooling and warming rates of the KVS were 683,000 and 612,000 °C/min, respectively, exceeding those of the control device., Conclusions: Our study clearly demonstrates that the KVS is a novel vitrification device for the cryopreservation of mouse embryos at the blastocyst and 2-cell stage.
- Published
- 2017
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32. Bioprocessing of tea oil fruit hull with acetic acid organosolv pretreatment in combination with alkaline H 2 O 2 .
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Tang S, Liu R, Sun FF, Dong C, Wang R, Gao Z, Zhang Z, Xiao Z, Li C, and Li H
- Abstract
Background: As a natural renewable biomass, the tea oil fruit hull (TOFH) mainly consists of lignocellulose, together with some bioactive substances. Our earlier work constructed a two-stage solvent-based process, including one aqueous ethanol organosolv extraction and an atmospheric glycerol organosolv (AGO) pretreatment, for bioprocessing of the TOFH into diverse bioproducts. However, the AGO pretreatment is not as selective as expected in removing the lignin from TOFH, resulting in the limited delignification and simultaneously high cellulose loss., Results: In this study, acetic acid organosolv (AAO) pretreatment was optimized with experimental design to fractionate the TOFH selectively. Alkaline hydrogen peroxide (AHP) pretreatment was used for further delignification. Results indicate that the AAO-AHP pretreatment had an extremely good selectivity at component fractionation, resulting in 92% delignification and 88% hemicellulose removal, with 87% cellulose retention. The pretreated substrate presented a remarkable enzymatic hydrolysis of 85% for 48 h at a low cellulase loading of 3 FPU/g dry mass. The hydrolyzability was correlated with the composition and structure of substrates by using scanning electron microscopy, confocal laser scanning microscopy, and X-ray diffraction., Conclusion: The mild AAO-AHP pretreatment is an environmentally benign and advantageous scheme for biorefinery of the agroforestry biomass into value-added bioproducts.
- Published
- 2017
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33. A biorefinery scheme to fractionate bamboo into high-grade dissolving pulp and ethanol.
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Yuan Z, Wen Y, Kapu NS, Beatson R, and Mark Martinez D
- Abstract
Background: Bamboo is a highly abundant source of biomass which is underutilized despite having a chemical composition and fiber structure similar as wood. The main challenge for the industrial processing of bamboo is the high level of silica, which forms water-insoluble precipitates negetively affecting the process systems. A cost-competitive and eco-friendly scheme for the production of high-purity dissolving grade pulp from bamboo not only requires a process for silica removal, but also needs to fully utilize all of the materials dissolved in the process which includes lignin, and cellulosic and hemicellulosic sugars as well as the silica. Many investigations have been carried out to resolve the silica issue, but none of them has led to a commercial process. In this work, alkaline pretreatment of bamboo was conducted to extract silica prior to pulping process. The silica-free substrate was used to produce high-grade dissolving pulp. The dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the spent liquors obtained from alkaline pretreatment and pulping process were recovered for providing high-value bio-based chemicals and fuel., Results: An integrated process which combines dissolving pulp production with the recovery of excellent sustainable biofuel and biochemical feedstocks is presented in this work. Pretreatment at 95 °C with 12% NaOH charge for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. After kraft pulping, xylanase treatment and cold caustic extraction, pulp with hemicellulose content of about 3.5% was obtained. This pulp, after bleaching, provided a cellulose acetate grade dissolving pulp with α-cellulose content higher than 97% and hemicellulose content less than 2%. The amount of silica and lignin that could be recovered from the process corresponded to 95 and 77.86% of the two components in the original chips, respectively. Enzymatic hydrolysis and fermentation of the concentrated and detoxified sugar mixture liquor showed that an ethanol recovery of 0.46 g/g sugar was achieved with 93.2% of hydrolyzed sugars being consumed. A mass balance of the overall process showed that 76.59 g of solids was recovered from 100 g (o.d.) of green bamboo., Conclusions: The present work proposes an integrated biorefinery process that contains alkaline pre-extraction, kraft pulping, enzyme treatment and cold caustic extraction for the production of high-grade dissolving pulp and recovery of silica, lignin, and hemicellulose from bamboo. This process could alleviate the silica-associated challenges and provide feedstocks for bio-based products, thereby allowing the improvement and expansion of bamboo utilization in industrial processes.
- Published
- 2017
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34. Evaluation of the two-step treatment with ionic liquids and alkali for enhancing enzymatic hydrolysis of Eucalyptus: chemical and anatomical changes.
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Li HY, Chen X, Wang CZ, Sun SN, and Sun RC
- Abstract
Background: The biomass recalcitrance resulting from its chemical compositions and physical structures impedes the conversion of biomass into fermentable sugars. Pretreatment is a necessary procedure to increase the cellulase accessibility for bioconversion of lignocelluloses into bioethanol. Alternatively, ionic liquids, a series of promising solvents, provide unique opportunities for pretreating a wide range of lignocellulosic materials. In this study, a two-step treatment including ionic liquids pretreatment and successive alkali fractionations was performed on Eucalyptus to achieve a high enzymatic digestibility. The compositional and structural changes of Eucalyptus cell walls and their possible effect on saccharification ratio were comprehensively investigated., Results: After the ionic liquids pretreatment, the cell walls became loose and even swelled, accompanying with the decrease of cellulose crystallinity. As compared to the simplex ionic liquids pretreatment, the integrated process resulted in the significant removal of hemicelluloses and lignin, enhancing the disruption of the cell walls and increasing the exposure of cellulose, which led to a higher conversion of cellulose to glucose. The glucose yield of Eucalyptus underwent the combination of [Bmim]OAc and alkali treatments reached the maximum (90.53 %), which was 6.6 times higher than that of the untreated Eucalyptus. The combination of chemical compositions and physical structure of Eucalyptus affected the efficiency of cellulose enzymatic hydrolysis. Especially, the changes of cellulose crystallinity played a major role in enhancing the enzymatic digestibility of Eucalyptus in this study., Conclusions: The two-step treatment with ionic liquids pretreatment and successive alkali fractionation can be considered as a promising method to improve the conversion of cellulose to glucose. The detailed information obtained about chemical and anatomical changes was helpful to understand the underlying mechanism of the integrated treatment process acting on Eucalyptus for enhancing enzymatic digestibility.
- Published
- 2016
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35. Industrially relevant hydrolyzability and fermentability of sugarcane bagasse improved effectively by glycerol organosolv pretreatment.
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Sun FF, Zhao X, Hong J, Tang Y, Wang L, Sun H, Li X, and Hu J
- Abstract
Background: Previous work has demonstrated that glycerol organosolv pretreatment can effectively improve the hydrolyzability of various lignocellulosic substrates. This pretreatment process strategy is ideal to integrate a commercially successful lignocellulosic and vegetable oil biorefinery industry. However, industrially relevant high-solid-loading hydrolyzability and fermentability of the pretreated substrates have yet to be considered for enzyme-based lignocellulosic biorefineries., Results: In this study, an AGO pretreatment of sugarcane bagasse was evaluated with regard to the component selectivity, structural modification, hydrolyzability, and fermentation of pretreated substrates. The results showed that the AGO pretreatment presented good component selectivity, removing approximately 70 % lignin and hemicellulose, respectively, from sugarcane bagasse with a near-intact preservation (94 %) of the overall cellulose. The pretreatment deconstructed the recalcitrant architecture of natural lignocellulosic biomass, thereby modifying the structure at the macro-/micrometer level (fiber size, surface area, average size, roughness) and supermolecular level (key chemical bond dissociation) of lignocellulosic substrates towards good hydrolyzability. Notably, extraordinarily few fermentation inhibitors (<0.2 g furfural and 5-hydromethyl furfural/kg feedstock) were generated from the AGO pretreatment process, which was apparently due to the prominent role of glycerol organic solvent in protecting monosaccharides against further degradation. The 72-h enzymatic hydrolysis of pretreated substrates at 15 % solid content achieved 90 % completion with Cellic CTec2 at 10 FPU/g dried substrate. With a simple nutrition (only 10 g/L (NH4)2SO4) addition, the fed-batch semi-SSF of AGO-pretreated substrates (30 % solid content) almost reached 50 g/L ethanol with cellulase preparation at 10 FPU/g dried substrate. These results have revealed that the pretreated substrate is susceptible and accessible to cellulase enzymes, thereafter exhibiting remarkable hydrolyzability and fermentability., Conclusion: The AGO pretreatment is a promising candidate for the current pretreatment process towards industrially relevant enzyme-based lignocellulosic biorefineries.
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- 2016
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36. Markedly improving asymmetric oxidation of 1-(4-methoxyphenyl) ethanol with Acetobacter sp. CCTCC M209061 cells by adding deep eutectic solvent in a two-phase system.
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Wei P, Liang J, Cheng J, Zong MH, and Lou WY
- Subjects
- Acetobacter drug effects, Oxidation-Reduction drug effects, Stereoisomerism, Acetobacter metabolism, Ethanol chemistry, Ethanol metabolism, Solvents pharmacology
- Abstract
Background: Enantiopure (S)-1-(4-methoxyphenyl) ethanol {(S)-MOPE} can be employed as an important synthon for the synthesis of cycloalkyl [b] indoles with the treatment function for general allergic response. To date, the biocatalytic resolution of racemic MOPE through asymmetric oxidation in the biphasic system has remained largely unexplored. Additionally, deep eutectic solvents (DESs), as a new class of promising green solvents, have recently gained increasing attention in biocatalysis for their excellent properties and many successful examples in biocatalytic processes. In this study, the biocatalytic asymmetric oxidation of MOPE to get (S)-MOPE using Acetobacter sp. CCTCC M209061 cells was investigated in different two-phase systems, and adding DES in a biphasic system was also explored to further improve the reaction efficiency of the biocatalytic oxidation., Results: Of all the examined water-immiscible organic solvents and ionic liquids (ILs), 1-butyl-3-methylimidazolium hexafluorophoshpate ([C4MIM][PF6]) afforded the best results, and consequently was selected as the second phase of a two-phase system for the asymmetric oxidation of MOPE with immobilized Acetobacter sp. CCTCC M209061 cells. For the reaction performed in the [C4MIM][PF6]/buffer biphasic system, under the optimized conditions, the initial reaction rate, the maximum conversion and the residual substrate e.e. recorded 97.8 μmol/min, 50.5 and >99.9 % after 10 h reaction. Furthermore, adding the DES [ChCl][Gly] (10 %, v/v) to the aqueous phase, the efficiency of the biocatalytic oxidation was rose markedly. The optimal substrate concentration and the initial reaction rate were significantly increased to 80 mmol/L and 124.0 μmol/min, respectively, and the reaction time was shortened to 7 h with 51.3 % conversion. The immobilized cell still retained over 72 % of its initial activity after 9 batches of successive reuse in the [C4MIM][PF6]/[ChCl][Gly]-containing buffer system. Additionally, the efficient biocatalytic process was feasible up to a 500-mL preparative scale., Conclusion: The biocatalytic asymmetric oxidation of MOPE with Acetobacter sp. CCTCC M209061 cells was successfully conducted in the [C4MIM][PF6]-containing biphasic system with high conversion and enantioselectivity, and the reaction efficiency was further enhanced by adding [ChCl][Gly] to the reaction system. The efficient biocatalytic process was promising for the preparation of enantiopure (S)-MOPE.
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- 2016
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37. A GH115 α-glucuronidase from Schizophyllum commune contributes to the synergistic enzymatic deconstruction of softwood glucuronoarabinoxylan.
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McKee LS, Sunner H, Anasontzis GE, Toriz G, Gatenholm P, Bulone V, Vilaplana F, and Olsson L
- Abstract
Background: Lignocellulosic biomass from softwood represents a valuable resource for the production of biofuels and bio-based materials as alternatives to traditional pulp and paper products. Hemicelluloses constitute an extremely heterogeneous fraction of the plant cell wall, as their molecular structures involve multiple monosaccharide components, glycosidic linkages, and decoration patterns. The complete enzymatic hydrolysis of wood hemicelluloses into monosaccharides is therefore a complex biochemical process that requires the activities of multiple degradative enzymes with complementary activities tailored to the structural features of a particular substrate. Glucuronoarabinoxylan (GAX) is a major hemicellulose component in softwood, and its structural complexity requires more enzyme specificities to achieve complete hydrolysis compared to glucuronoxylans from hardwood and arabinoxylans from grasses., Results: We report the characterisation of a recombinant α-glucuronidase (Agu115) from Schizophyllum commune capable of removing (4-O-methyl)-glucuronic acid ((Me)GlcA) residues from polymeric and oligomeric xylan. The enzyme is required for the complete deconstruction of spruce glucuronoarabinoxylan (GAX) and acts synergistically with other xylan-degrading enzymes, specifically a xylanase (Xyn10C), an α-l-arabinofuranosidase (AbfA), and a β-xylosidase (XynB). Each enzyme in this mixture showed varying degrees of potentiation by the other activities, likely due to increased physical access to their respective target monosaccharides. The exo-acting Agu115 and AbfA were unable to remove all of their respective target side chain decorations from GAX, but their specific activity was significantly boosted by the addition of the endo-Xyn10C xylanase. We demonstrate that the proposed enzymatic cocktail (Agu115 with AbfA, Xyn10C and XynB) achieved almost complete conversion of GAX to arabinofuranose (Araf), xylopyranose (Xylp), and MeGlcA monosaccharides. Addition of Agu115 to the enzymatic cocktail contributes specifically to 25 % of the conversion. However, traces of residual oligosaccharides resistant to this combination of enzymes were still present after deconstruction, due to steric hindrances to enzyme access to the substrate., Conclusions: Our GH115 α-glucuronidase is capable of finely tailoring the molecular structure of softwood GAX, and contributes to the almost complete saccharification of GAX in synergy with other exo- and endo-xylan-acting enzymes. This has great relevance for the cost-efficient production of biofuels from softwood lignocellulose.
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- 2016
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38. How chip size impacts steam pretreatment effectiveness for biological conversion of poplar wood into fermentable sugars.
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DeMartini JD, Foston M, Meng X, Jung S, Kumar R, Ragauskas AJ, and Wyman CE
- Abstract
Background: Woody biomass is highly recalcitrant to enzymatic sugar release and often requires significant size reduction and severe pretreatments to achieve economically viable sugar yields in biological production of sustainable fuels and chemicals. However, because mechanical size reduction of woody biomass can consume significant amounts of energy, it is desirable to minimize size reduction and instead pretreat larger wood chips prior to biological conversion. To date, however, most laboratory research has been performed on materials that are significantly smaller than applicable in a commercial setting. As a result, there is a limited understanding of the effects that larger biomass particle size has on the effectiveness of steam explosion pretreatment and subsequent enzymatic hydrolysis of wood chips., Results: To address these concerns, novel downscaled analysis and high throughput pretreatment and hydrolysis (HTPH) were applied to examine whether differences exist in the composition and digestibility within a single pretreated wood chip due to heterogeneous pretreatment across its thickness. Heat transfer modeling, Simons' stain testing, magnetic resonance imaging (MRI), and scanning electron microscopy (SEM) were applied to probe the effects of pretreatment within and between pretreated wood samples to shed light on potential causes of variation, pointing to enzyme accessibility (i.e., pore size) distribution being a key factor dictating enzyme digestibility in these samples. Application of these techniques demonstrated that the effectiveness of pretreatment of Populus tremuloides can vary substantially over the chip thickness at short pretreatment times, resulting in spatial digestibility effects and overall lower sugar yields in subsequent enzymatic hydrolysis., Conclusions: These results indicate that rapid decompression pretreatments (e.g., steam explosion) that specifically alter accessibility at lower temperature conditions are well suited for larger wood chips due to the non-uniformity in temperature and digestibility profiles that can result from high temperature and short pretreatment times. Furthermore, this study also demonstrated that wood chips were hydrated primarily through the natural pore structure during pretreatment, suggesting that preserving the natural grain and transport systems in wood during storage and chipping processes could likely promote pretreatment efficacy and uniformity.
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- 2015
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39. Functional relationship of furfural yields and the hemicellulose-derived sugars in the hydrolysates from corncob by microwave-assisted hydrothermal pretreatment.
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Li H, Chen X, Ren J, Deng H, Peng F, and Sun R
- Abstract
Background: Corncob as one of the most suitable feedstock for the production of a variety of high-value-added chemicals is receiving increasing attention worldwide because of the characteristics of high carbohydrate (cellulose and hemicelluloses) contents and high energy densities. Furfural produced from hemicelluloses is a highly versatile and key feedstock used in the manufacture of a wide range of biofuel and important chemicals in different fields. Achieving high furfural yields from corncob combining green approaches and efficient equipment has the promising potential for biomass-to-biofuel technologies. To understand the dissolving mechanism of corncob sugars and reveal the relationship between the hydrolysate composition and furfural yields, a two-step approach was proposed using microwave-assisted hydrothermal pretreatment and subsequently heterogeneous catalytic process., Results: Released hemicelluloses in the first stage were mainly in forms of monosaccharide, oligosaccharides, and water-soluble polysaccharide. Hydrolysates with the maximum xylose content (99.94 mg g(-1), 160 °C, 90 min), the maximum xylobiose content (20.89 mg g(-1), 180 °C, 15 min), and the maximum total xylose content in monosaccharide and oligosaccharides (DP ≤ 6) (272.06 mg g(-1), 160 °C, 60 min) were further converted to furfural using tin-loaded montmorillonite as the catalyst in a biphasic system. The highest furfural yield (57.80 %) was obtained at 190 °C for 10 min from hydrolysates with the maximum xylose content. Moreover, controlled experiments showed that furfural yields from corncob hydrolysates were higher than those from the pure xylose solutions, and lower initial xylose concentration may be in favor of the furfural production., Conclusions: This work provides an efficient approach to produce furfural by a two-step process for the biomass-to-biofuel industry. Results indicated that the production of furfural from biomass raw materials can be controlled by the depolymerization degree of hemicelluloses.
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- 2015
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40. Evaluating the effects of biocompatible cholinium ionic liquids on microbial lipid production by Trichosporon fermentans.
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Liu L, Hu Y, Wen P, Li N, Zong M, Ou-Yang B, and Wu H
- Abstract
Background: Microbial lipid is a potential raw material for large-scale biodiesel production and lignocellulosic hydrolysate has been considered as promising low-cost substrate for lipid fermentation. Lignocellulosic biomass needs to be pretreated before enzymatic hydrolysis, and biocompatible cholinium ionic liquids (ILs) have been demonstrated to be highly efficient for pretreatment. However, the impact of these ILs residues in hydrolysates on downstream biotransformation remains unknown. Therefore, the influence of three typical cholinium ILs on the lipid production by Trichosporon fermentans was first investigated., Results: The cell growth of T. fermentans was stimulated in the presence of cholinium lysine ([Ch][Lys]) and cholinium serine ([Ch][Ser]), while the lipid accumulation was inhibited by [Ch][Lys]) and [Ch][Ser]. Both cell growth and lipid accumulation of T. fermentans were inhibited in the presence of cholinium acetate ([Ch][OAc]). Despite the reduction in lipid content, the lipid production by T. fermentans was improved in the presence of low concentrations of [Ch][Lys] (≤30 mM) and [Ch][Ser] (≤20 mM) due to the remarkable increase of biomass. It was found that cholinium cation had minor influence on lipid production. However, the anions of [Ch][Lys] and [Ch][Ser] could be assimilated as nitrogen source by T. fermentans and the reduced C/N ratio accounts for the inhibition of lipid accumulation, which could be alleviated by improving C/N ratio of medium. In addition, the anion of [Ch][OAc] could be metabolized by T. fermentans, leading to a rapid alkaline-pH shift and strong inhibition of lipid production. And this inhibitory effect on lipid production could be significantly reduced by controlling culture pH., Conclusions: The anions of [Ch][Lys], [Ch][Ser] and [Ch][OAc] play an important role in affecting the cell growth and lipid accumulation of T. fermentans, and the inhibition of these three ILs on lipid production can be alleviated by careful fermentation condition control. Hence, T. fermentans is a promising strain for microbial lipid production from cholinium ILs-pretreated lignocellulosic hydrolysates.
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- 2015
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41. High titer and yield ethanol production from undetoxified whole slurry of Douglas-fir forest residue using pH profiling in SPORL.
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Cheng J, Leu SY, Zhu J, and Gleisner R
- Abstract
Background: Forest residue is one of the most cost-effective feedstock for biofuel production. It has relatively high bulk density and can be harvested year round, advantageous for reducing transportation cost and eliminating onsite storage. However, forest residues, especially those from softwood species, are highly recalcitrant to biochemical conversion. A severe pretreatment for removing this recalcitrance can result in increased sugar degradation to inhibitors and hence cause difficulties in fermentation at high solid loadings. Here, we presented high titer ethanol production from Douglas-fir forest residue without detoxification. The strong recalcitrance of the Douglas-fir residue was removed by sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL). Sugar degradation to inhibitors was substantially reduced using a novel approach of "pH profiling" by delaying acid application in pretreatment, which facilitated the simultaneous enzymatic saccharification and fermentation of undetoxified whole slurry at a solid loading of 21%., Results: "pH profiling" reduced furan production by approximately 70% in using SPORL pretreating Douglas-fir forest residue (FS-10) comparing with the control run while without sacrificing enzymatic saccharification of the resultant substrate. pH profiling also reduced carbohydrate degradation. The improved carbohydrate yield in pretreated solids and reduced fermentation inhibitors with pH profiling resulted in a terminal ethanol titer of 48.9 ± 1.4 g/L and yield of 297 ± 9 L/tonne FS-10, which are substantially higher, i.e., by 27% in titer and by 38% in yield, than those of a control SPORL run without pH profiling., Conclusions: Economical and large-volume production of commodity biofuels requires the utilization of feedstocks with low value (therefore low cost) and sustainably producible in large quantities, such as forest residues. However, most existing pretreatment technologies cannot remove the strong recalcitrance of forest residues to produce practically fermentable high titer sugars. Here, we demonstrated a commercially scalable and efficient technology capable of removing the strong recalcitrant nature of forest residues using "pH profiling" together with "low temperature SPORL". The resultant pretreated whole slurry of a Douglas-fir forest residue using this technology can be easily processed at high solids of 21% without detoxification to achieve a high ethanol yield of 297 L/tonne at 48.9 g/L. Graphical AbstractGraphic table of content.
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- 2015
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42. Using ionic liquids in whole-cell biocatalysis for the nucleoside acylation.
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Yang M, Wu H, Lian Y, Li X, Ren Y, Lai F, and Zhao G
- Subjects
- Acylation, Catalysis, Nucleosides metabolism, Pseudomonas fluorescens metabolism, Ionic Liquids chemistry, Nucleosides chemistry, Pseudomonas fluorescens chemistry
- Abstract
Background: The use of biocatalysts has become an increasingly attractive alternative to traditional chemical methods, due to the high selectivity, mild reaction conditions and environmentally-friendly processes in nonaqueous catalysis of nucleosids. However, the extensive use of organic solvents may generally suffer from sever drawbacks such as volatileness and toxicity to the environment and lower activity of the biocatalyst. Recently, ionic liquids are considered promising solvents for nonaqueous biocatalysis of polyhydroxyl compounds as ILs are environmental-friendly., Results: In this research, we developed new IL-containing reaction systems for synthesis of long chain nucleoside ester catalyzed by Pseudomonas fluorescens whole-cells. Various ILs exerted significant but different effects on the bio-reaction. And their effects were closely related with both the anions and cations of the ILs. Use of 10% [BMI][PF6]/THF gave high reaction efficiency of arabinocytosine laurate synthesis, in which the initial rate, product yield and 5'-regioselectivity reached 2.34 mmol/L·h, 81.1% and >99%, respectively. Furthermore, SEM analysis revealed that ILs can alter the cell surface morphology, improve the permeability of cell envelopes and thus facilitate the mass transfer of substrates to the active sites of cell-bound enzymes., Conclusion: Our research demonstrated the potential of ILs as promising reaction medium for achieving highly efficient and regioselective whole-cell catalysis.
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- 2014
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43. Improving the enzymatic hydrolysis of thermo-mechanical fiber from Eucalyptus urophylla by a combination of hydrothermal pretreatment and alkali fractionation.
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Sun S, Cao X, Sun S, Xu F, Song X, Sun RC, and Jones GL
- Abstract
Background: The recalcitrance of lignocellulosic biomass is a major limitation for its conversion into biofuels by enzymatic hydrolysis. The use of a pretreatment technology is an essential step to diminish biomass recalcitrance for bioethanol production. In this study, a two-step pretreatment using hydrothermal pretreatment at various temperatures and alkali fractionation was performed on eucalyptus fiber. The detailed chemical composition, physicochemical characteristics, and morphology of the pretreated fibers in each of the fractions were evaluated to advance the performance of eucalyptus fiber in enzymatic digestibility., Results: The hydrothermal pretreatment (100 to 220°C) significantly degraded hemicelluloses, resulting in an increased crystallinity of the pretreated fibers. However, as the pretreatment temperature reached 240°C, partial cellulose was degraded, resulting in a reduced crystallinity of cellulose. As compared to the hydrothermal pretreatment alone, a combination of hydrothermal and alkali treatments significantly removed hemicelluloses and lignin, resulting in an improved enzymatic hydrolysis of the cellulose-rich fractions. As compared with the raw fiber, the enzymatic hydrolysis rate increased 1.1 to 8.5 times as the hydrothermal pretreatment temperature increased from 100 to 240°C. Interestingly, after a combination of hydrothermal pretreatment and alkali fractionation, the enzymatic hydrolysis rate increased 3.7 to 9.2 times. Taking into consideration the consumption of energy and the production of xylo-oligosaccharides and lignin, an optimum pretreatment condition was found to be hydrothermal pretreatment at 180°C for 30 min and alkali fractionation with 2% NaOH at 90°C for 2.5 h, in which 66.3% cellulose was converted into glucose by enzymatic hydrolysis., Conclusions: The combination of hydrothermal pretreatment and alkali fractionation was a promising method to remove hemicelluloses and lignin as well as overcome the biomass recalcitrance for enzymatic hydrolysis from eucalyptus fiber. In addition, the various techniques applied in this work constituted an efficient approach to understand the underlying chemical and morphological changes of the cellulose-rich fractions.
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- 2014
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44. Agave proves to be a low recalcitrant lignocellulosic feedstock for biofuels production on semi-arid lands.
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Li H, Pattathil S, Foston MB, Ding SY, Kumar R, Gao X, Mittal A, Yarbrough JM, Himmel ME, Ragauskas AJ, Hahn MG, and Wyman CE
- Abstract
Background: Agave, which is well known for tequila and other liquor production in Mexico, has recently gained attention because of its attractive potential to launch sustainable bioenergy feedstock solutions for semi-arid and arid lands. It was previously found that agave cell walls contain low lignin and relatively diverse non-cellulosic polysaccharides, suggesting unique recalcitrant features when compared to conventional C4 and C3 plants., Results: Here, we report sugar release data from fungal enzymatic hydrolysis of non-pretreated and hydrothermally pretreated biomass that shows agave to be much less recalcitrant to deconstruction than poplar or switchgrass. In fact, non-pretreated agave has a sugar release five to eight times greater than that of poplar wood and switchgrass . Meanwhile, state of the art techniques including glycome profiling, nuclear magnetic resonance (NMR), Simon's Stain, confocal laser scanning microscopy and so forth, were applied to measure interactions of non-cellulosic wall components, cell wall hydrophilicity, and enzyme accessibility to identify key structural features that make agave cell walls less resistant to biological deconstruction when compared to poplar and switchgrass., Conclusions: This study systematically evaluated the recalcitrant features of agave plants towards biofuels applications. The results show that not only does agave present great promise for feeding biorefineries on semi-arid and arid lands, but also show the value of studying agave's low recalcitrance for developments in improving cellulosic energy crops.
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- 2014
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45. Fed-batch SSCF using steam-exploded wheat straw at high dry matter consistencies and a xylose-fermenting Saccharomyces cerevisiae strain: effect of laccase supplementation.
- Author
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Moreno AD, Tomás-Pejó E, Ibarra D, Ballesteros M, and Olsson L
- Abstract
Background: Lignocellulosic bioethanol is expected to play an important role in fossil fuel replacement in the short term. Process integration, improvements in water economy, and increased ethanol titers are key considerations for cost-effective large-scale production. The use of whole steam-pretreated slurries under high dry matter (DM) conditions and conversion of all fermentable sugars offer promising alternatives to achieve these goals., Results: Wheat straw slurry obtained from steam explosion showed high concentrations of degradation compounds, hindering the fermentation performance of the evolved xylose-recombinant Saccharomyces cerevisiae KE6-12 strain. Fermentability tests using the liquid fraction showed a higher number of colony-forming units (CFU) and higher xylose consumption rates when treating the medium with laccase. During batch simultaneous saccharification and co-fermentation (SSCF) processes, cell growth was totally inhibited at 12% DM (w/v) in untreated slurries. However, under these conditions laccase treatment prior to addition of yeast reduced the total phenolic content of the slurry and enabled the fermentation. During this process, an ethanol concentration of 19 g/L was obtained, corresponding to an ethanol yield of 39% of the theoretical yield. By changing the operation from batch mode to fed-batch mode, the concentration of inhibitors at the start of the process was reduced and 8 g/L of ethanol were obtained in untreated slurries with a final consistency of 16% DM (w/v). When fed-batch SSCF medium was supplemented with laccase 33 hours after yeast inoculation, no effect on ethanol yield or cell viability was found compared to untreated fermentations. However, if the laccase supplementation (21 hours after yeast inoculation) took place before the first addition of substrate (at 25 hours), improved cell viability and an increased ethanol titer of up to 32 g/L (51% of the theoretical) were found., Conclusions: Laccase treatment in SSCF processes reduces the inhibitory effect that degradation compounds have on the fermenting microorganism. Furthermore, in combination with fed-batch operational mode, laccase supplementation allows the fermentation of wheat straw slurry at high DM consistencies, improving final ethanol concentrations and yields.
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- 2013
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46. Lignosulfonate-mediated cellulase adsorption: enhanced enzymatic saccharification of lignocellulose through weakening nonproductive binding to lignin.
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Wang Z, Zhu J, Fu Y, Qin M, Shao Z, Jiang J, and Yang F
- Abstract
Background: Thermochemical pretreatment of lignocellulose is crucial to bioconversion in the fields of biorefinery and biofuels. However, the enzyme inhibitors in pretreatment hydrolysate make solid substrate washing and hydrolysate detoxification indispensable prior to enzymatic hydrolysis. Sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) is a relatively new process, but has demonstrated robust performance for sugar and biofuel production from woody biomass in terms of yield and energy efficiency. This study demonstrated the advantage of SPORL pretreatment whereby the presentation of lignosulfonate (LS) renders the hydrolysate non-inhibitory to cellulase (Cel) due to the formation of lignosulfonate-cellulase complexes (LCCs) which can mediate the Cel adsorption between lignin and cellulose, contrary to the conventional belief that pretreatment hydrolysate inhibits the enzymatic hydrolysis unless detoxified., Results: Particular emphasis was made on the formation mechanisms and stability phase of LCCs, the electrostatic interaction between LCCs and lignin, and the redistributed Cel adsorption between lignin and cellulose. The study found that LS, the byproduct of SPORL pretreatment, behaves as a polyelectrolyte to form LCCs with Cel by associating to the oppositely charged groups of protein. Compared to Cel, the zeta potential of LCCs is more negative and adjustable by altering the molar ratio of LS to Cel, and thereby LCCs have the ability to mitigate the nonproductive binding of Cel to lignin because of the enlarged electrostatic repulsion. Experimental results showed that the benefit from the reduced nonproductive binding outweighed the detrimental effects from the inhibitors in pretreatment hydrolysate. Specifically, the glucan conversions of solid substrate from poplar and lodgepole pine were greatly elevated by 25.9% and 31.8%, respectively, with the complete addition of the corresponding hydrolysate. This contradicts the well-acknowledged concept in the fields of biofuels and biorefinery that the pretreatment hydrolysate is inhibitory to enzymes., Conclusions: The results reported in this study also suggest significant advantages of SPORL pretreatment in terms of water consumption and process integration, that is, it should abolish the steps of solid substrate washing and pretreatment hydrolysate detoxification for direct simultaneous saccharification and combined fermentation (SSCombF) of enzymatic and pretreatment hydrolysate, thereby facilitating bioprocess consolidation. Furthermore, this study not only has practical significance to biorefinery and bioenergy, but it also provides scientific importance to the molecular design of composite enzyme-polyelectrolyte systems, such as immobilized enzymes and enzyme activators, as well as to the design of enzyme separation processes using water-soluble polyelectrolytes.
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- 2013
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47. The fate of lignin during hydrothermal pretreatment.
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Trajano HL, Engle NL, Foston M, Ragauskas AJ, Tschaplinski TJ, and Wyman CE
- Abstract
Background: Effective enzymatic hydrolysis of lignocellulosic biomass benefits from lignin removal, relocation, and/or modification during hydrothermal pretreatment. Phase transition, depolymerization/repolymerization, and solubility effects may all influence these lignin changes. To better understand how lignin is altered, Populus trichocarpa x P. deltoides wood samples and cellulolytic enzyme lignin (CEL) isolated from P. trichocarpa x P. deltoides were subjected to batch and flowthrough pretreatments. The residual solids and liquid hydrolysate were characterized by gel permeation chromatography, heteronuclear single quantum coherence NMR, compositional analysis, and gas chromatography-mass spectrometry., Results: Changes in the structure of the solids recovered after the pretreatment of CEL and the production of aromatic monomers point strongly to depolymerization and condensation being primary mechanisms for lignin extraction and redeposition. The differences in lignin removal and phenolic compound production from native P. trichocarpa x P. deltoides and CEL suggested that lignin-carbohydrate interactions increased lignin extraction and the extractability of syringyl groups relative to guaiacyl groups., Conclusions: These insights into delignification during hydrothermal pretreatment point to desirable pretreatment strategies and plant modifications. Because depolymerization followed by repolymerization appears to be the dominant mode of lignin modification, limiting the residence time of depolymerized lignin moieties in the bulk liquid phase should reduce lignin content in pretreated biomass. In addition, the increase in lignin removal in the presence of polysaccharides suggests that increasing lignin-carbohydrate cross-links in biomass would increase delignification during pretreatment.
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- 2013
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48. Assessing the molecular structure basis for biomass recalcitrance during dilute acid and hydrothermal pretreatments.
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Pu Y, Hu F, Huang F, Davison BH, and Ragauskas AJ
- Abstract
The production of cellulosic ethanol from biomass is considered a promising alternative to reliance on diminishing supplies of fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The conversion of lignocellulosic biomass to biofuels through a biological route usually suffers from the intrinsic recalcitrance of biomass owing to the complicated structure of plant cell walls. Currently, a pretreatment step that can effectively reduce biomass recalcitrance is generally required to make the polysaccharide fractions locked in the intricacy of plant cell walls to become more accessible and amenable to enzymatic hydrolysis. Dilute acid and hydrothermal pretreatments are attractive and among the most promising pretreatment technologies that enhance sugar release performance. This review highlights our recent understanding on molecular structure basis for recalcitrance, with emphasis on structural transformation of major biomass biopolymers (i.e., cellulose, hemicellulose, and lignin) related to the reduction of recalcitrance during dilute acid and hydrothermal pretreatments. The effects of these two pretreatments on biomass porosity as well as its contribution on reduced recalcitrance are also discussed.
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- 2013
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49. Immobilization of Acetobacter sp. CCTCC M209061 for efficient asymmetric reduction of ketones and biocatalyst recycling.
- Author
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Chen XH, Wang XT, Lou WY, Li Y, Wu H, Zong MH, Smith TJ, and Chen XD
- Subjects
- Alginates chemistry, Alkynes chemistry, Alkynes metabolism, Biocatalysis, Butanols chemistry, Butanols metabolism, Cells, Immobilized metabolism, Chitosan chemistry, Glucuronic Acid chemistry, Hexuronic Acids chemistry, Hydrogen-Ion Concentration, Ketones chemistry, Oxidation-Reduction, Solvents chemistry, Stereoisomerism, Temperature, omega-Chloroacetophenone chemistry, omega-Chloroacetophenone metabolism, Acetobacter metabolism, Ketones metabolism
- Abstract
Background: The bacterium Acetobacter sp. CCTCC M209061 is a promising whole-cell biocatalyst with exclusive anti-Prelog stereoselectivity for the reduction of prochiral ketones that can be used to make valuable chiral alcohols such as (R)-4-(trimethylsilyl)-3-butyn-2-ol. Although it has promising catalytic properties, its stability and reusability are relatively poor compared to other biocatalysts. Hence, we explored various materials for immobilizing the active cells, in order to improve the operational stability of biocatalyst., Results: It was found that Ca-alginate give the best immobilized biocatalyst, which was then coated with chitosan to further improve its mechanical strength and swelling-resistance properties. Conditions were optimized for formation of reusable immobilized beads which can be used for repeated batch asymmetric reduction of 4'-chloroacetophenone. The optimized immobilized biocatalyst was very promising, with a specific activity of 85% that of the free-cell biocatalyst (34.66 μmol/min/g dw of cells for immobilized catalyst vs 40.54 μmol/min/g for free cells in the asymmetric reduction of 4'-chloroacetophenone). The immobilized cells showed better thermal stability, pH stability, solvent tolerance and storability compared with free cells. After 25 cycles reaction, the immobilized beads still retained >50% catalytic activity, which was 3.5 times higher than degree of retention of activity by free cells reused in a similar way. The cells could be recultured in the beads to regain full activity and perform a further 25 cycles of the reduction reaction. The external mass transfer resistances were negligible as deduced from Damkohler modulus Da < <1, and internal mass transfer restriction affected the reduction action but was not the principal rate-controlling step according to effectiveness factors η < 1 and Thiele modulus 0.3<∅ <1., Conclusions: Ca-alginate coated with chitosan is a highly effective material for immobilization of Acetobacter sp. CCTCC M209061 cells for repeated use in the asymmetric reduction of ketones. Only a small cost in terms of the slightly lower catalytic activity compared to free cells could give highly practicable immobilized biocatalyst.
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- 2012
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50. Efficient anti-Prelog enantioselective reduction of acetyltrimethylsilane to (R)-1-trimethylsilylethanol by immobilized Candida parapsilosis CCTCC M203011 cells in ionic liquid-based biphasic systems.
- Author
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Zhang BB, Cheng J, Lou WY, Wang P, and Zong MH
- Subjects
- Biocatalysis, Cells, Immobilized metabolism, Hydrogen-Ion Concentration, Imidazoles chemistry, Microbial Viability, Oxidation-Reduction, Stereoisomerism, Substrate Specificity, Temperature, Candida metabolism, Ionic Liquids chemistry, Trimethylsilyl Compounds chemistry
- Abstract
Background: Biocatalytic asymmetric reductions with whole cells can offer high enantioselectivity, environmentally benign processes and energy-effective operations and thus are of great interest. The application of whole cell-mediated bioreduction is often restricted if substrate and product have low water solubility and/or high toxicity to the biocatalyst. Many studies have shown that a biphasic system is often useful in this instance. Hence, we developed efficient biphasic reaction systems with biocompatible water-immiscible ionic liquids (ILs), to improve the biocatalytic anti-Prelog enantioselective reduction of acetyltrimethylsilane (ATMS) to (R)-1-trimethylsilylethanol {(R)-1-TMSE}, which is key synthon for a large number of silicon-containing drugs, using immobilized Candida parapsilosis CCTCC M203011 cells as the biocatalyst., Results: It was found that the substrate ATMS and the product 1-TMSE exerted pronounced toxicity to immobilized Candida parapsilosis CCTCC M203011 cells. The biocompatible water-immiscible ILs can be applied as a substrate reservoir and in situ extractant for the product, thus greatly enhancing the efficiency of the biocatalytic process and the operational stability of the cells as compared to the IL-free aqueous system. Various ILs exerted significant but different effects on the bioreduction and the performances of biocatalysts were closely related to the kinds and combination of cation and anion of ILs. Among all the water-immiscible ILs investigated, the best results were observed in 1-butyl-3-methylimidazolium hexafluorophosphate (C(4)mim·PF(6))/buffer biphasic system. Furthermore, it was shown that the optimum substrate concentration, volume ratio of buffer to IL, buffer pH, reaction temperature and shaking rate for the bioreduction were 120 mM, 8/1 (v/v), 6.0, 30°C and 180 r/min, respectively. Under these optimized conditions, the initial reaction rate, the maximum yield and the product e.e. were 8.1 μmol/min g(cwm), 98.6% and >99%, respectively. The efficient whole-cell biocatalytic process was shown to be feasible on a 450-mL scale. Moreover, the immobilized cells remained around 87% of their initial activity even after being used repeatedly for 8 batches in the C(4)mim·PF(6)/buffer biphasic system, exhibiting excellent operational stability., Conclusions: For the first time, we have successfully utilized immobilized Candida parapsilosis CCTCC M203011 cells, for efficiently catalyzing anti-Prelog enantioselective reduction of ATMS to enantiopure (R)-1-TMSE in the C(4)mim·PF(6)/buffer biphasic system. The substantially improved biocatalytic process appears to be effective and competitive on a preparative scale.
- Published
- 2012
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