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A highly stable Pd-loaded N-doped carbon catalyst (ACNpd) for phenol hydrogenation was prepared from chitosan by hydrothermal carbonization. ACNpd does not require a reduction step before catalytic use due to the Pd in the as-prepared catalyst mainly exists in the form of Pd0 (80%). The carbon support involves N-containing groups such as pyridinic nitrogen and pyrrolic nitrogen, which could provide basic sites to adsorb phenol effectively. The as-fabricated ACNpd shows high catalytic performance with turnover frequency (TOF) of 29.34 h−1. Accordingly, a phenol conversion of 100% and a cyclohexanone selectivity of 99.1% are achieved in 5 h at 100 °C and 1 MPa H2. This outstanding performance is attributed to the synergetic effects of the Pd particles, the N-functional groups, and the Lewis acid sites on the support. The carbon support presents intrinsic Lewis acid sites due to its electrophilicity, and Pd doping further increases the strength of such acid sites as it causes electron-deficient structural features. Moreover, the Lewis acid sites inhibit the over-hydrogenation from cyclohexanone to cyclohexanol. This study provides new insights into the application of functional biomass-based carbon materials as catalyst supports.

Objective To evaluate intravenous scleral and intracameral aqueous angiography in normotensive (n = 4) and hypertensive glaucomatous (n = 6) ADAMTS10-mutant canine eyes. Animals studied Ten ADAMTS10-mutant dogs were used in this study. Procedures Dogs were sedated and one eye from each dog underwent scleral angiography following intravenous injection of 0.25% indocyanine green (ICG). After a 24-h recovery period, the same eye underwent aqueous angiography via intracameral administration of ICG. Imaging of identical scleral sectors from the same eye was performed using a Heidelberg Spectralis® Confocal Scanning Laser Ophthalmoscope. Intrascleral vessel depth and lumen diameters were measured using Heidelberg Spectralis® optical coherence tomography and computer software. Results Scleral angiography permitted visualization of vascular components associated with conventional aqueous humor outflow pathways with an average time from injection to fluorescence of 35.8 ± 10.6 s (mean ± SD). Two normotensive eyes (2/10;20%) demonstrated turbulent dye movement, while 4 hypertensive eyes (4/10;40%) exhibited laminar flow. Aqueous angiography demonstrated dye fluorescence within the post-trabecular conventional aqueous humor outflow pathways in all 10 eyes at 34.3 ± 11.0 s post-injection. Sectoral and dynamic outflow patterns were observed primarily within the superotemporal sector in nine eyes (9/10; 90%). Seven eyes (7/10; 70%) demonstrated pulsatile dye movement and five eyes (5/10; 50%) exhibited laminar flow. The degree of laminar movement of dye was greatest in hypertensive eyes. Vessel lumen diameters measured 133.85 ± 28.36 µm and 161.18 ± 6.02 µm in hypertensive and normotensive eyes, respectively. Conclusions Aqueous angiography allowed for visualization of fluorescent dye in the superotemporal sclera. Laminar flow and smaller lumen vessels were observed mainly in hypertensive eyes.

The accumulation of non-degradable petrochemical plastics imposes a significant threat to the environment and ecosystems. We addressed this challenge by designing a new type of phototunable plastics based on the unique lignin chemistry to enable readily end-life recycling. The advanced material design leveraged the efficient photocatalytic lignin depolymerization by ZnO nanoparticles to build lignin-polymethyl methacrylate (PMMA)-ZnO blends. We first demonstrated the highly effective phototunable lignin depolymerization in the complex polymer blend matrix and explored the molecular mechanisms. The technical barriers of mechanical property and recycling processing were then addressed by a new blend design with lignin core grafted with PMMA polymer. The new process has resulted in a new type of PMMA-g-lignin blend, which significantly improved the mechanical properties, making it comparable to PMMA alone. More importantly, the mechanical properties of the UV-treated blend decreased drastically in the new design, whereas the properties did not reduce in the non-grafted blends upon UV exposure. The results highlighted that the new blend design based on graftization maximized the impact of lignin depolymerization on blend structure and recyclability. Based on the results, we developed a process integrating UV and alkaline treatments to recycle PMMA for plastics and fractionated lignin for bioconversion or other applications in the new phototunable plastics.

PRMT5 and its substrate adaptor proteins (SAPs), pICln and Riok1, are synthetic lethal dependencies in MTAP-deleted cancer cells. SAPs share a conserved PRMT5 binding motif (PBM) which mediates binding to a surface of PRMT5 distal to the catalytic site. This interaction is required for methylation of several PRMT5 substrates, including histone and spliceosome complexes. We screened for small molecule inhibitors of the PRMT5-PBM interaction and validated a compound series which binds to the PRMT5-PBM interface and directly inhibits binding of SAPs. Mode of action studies revealed the formation of a covalent bond between a halogenated pyridazinone group and cysteine 278 of PRMT5. Optimization of the starting hit produced a lead compound, BRD0639, which engages the target in cells, disrupts PRMT5-RIOK1 complexes, and reduces substrate methylation. BRD0639 is a first-in-class PBM-competitive inhibitor that can support studies of PBM-dependent PRMT5 activities and the development of novel PRMT5 inhibitors that selectively target these functions.

Purpose To review the current published literature on the use of OCT angiography (OCTA) to help detect changes associated with the diagnosis of primary open-angle glaucoma. Methods Searches of the peer-reviewed literature were conducted in March 2018, June 2018, April 2019, December 2019, and June 2020 in the PubMed and Cochrane Library databases. Abstracts of 459 articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 75 articles were selected and the panel methodologist rated them for strength of evidence. Three articles were rated level I and 57 articles were rated level II. The 15 level III articles were excluded. Results OCT angiography can detect decreased capillary vessel density within the peripapillary nerve fiber layer (level II) and macula (level I and II) in patients with suspected glaucoma, preperimetric glaucoma, and perimetric glaucoma. The degree of vessel density loss correlates significantly with glaucoma severity both overall and topographically (level II) as well as longitudinally (level I). For differentiating glaucomatous from healthy eyes, some studies found that peripapillary and macular vessel density measurements by OCTA show a diagnostic ability (area under the receiver operating characteristic curve) that is comparable with structural OCT retinal nerve fiber and ganglion cell thickness measurements, whereas other studies found that structural OCT measurements perform better. Choroidal or deep-layer microvasculature dropout as measured by OCTA is also associated with glaucoma damage (level I and II). Lower peripapillary and macular vessel density and choroidal microvasculature dropout are associated with faster rates of disease progression (level I and II). Conclusions Vessel density loss associated with glaucoma can be detected by OCTA. Peripapillary, macular, and choroidal vessel density parameters may complement visual field and structural OCT measurements in the diagnosis of glaucoma.

Summary The objective of this study was to review the antifungal susceptibility of clinical mould isolates performed by the New Zealand Mycology Reference Laboratory. Isolates were either local or referred for testing from other New Zealand laboratories. All isolates were tested by the broth colorimetric microdilution method, Sensititre YeastOne (SYO). Epidemiological cut-off values (ECVs) derived from either the Clinical and Laboratory Standards Institute (CLSI) method or SYO were used to determine the proportion of non-wild type (non-WT) isolates, i.e., those with an increased likelihood to harbour acquired mechanisms of resistance. A total of 614 isolates were tested. Most isolates (55%) were from the respiratory tract followed by musculoskeletal tissue (17%), eye (10%) and abdomen (5%). The azoles had similar activity except for voriconazole which was less active against the Mucorales. The echinocandins had good activity against Aspergillus spp., other hyaline moulds and dematiaceous isolates but were inactive against Fusarium spp., Lomentospora prolificans and the Mucorales. Amphotericin B had best activity against the Mucorales. The two least susceptible groups were Fusarium spp. and L. prolificans isolates. Three Aspergillus isolates were non-WT for amphotericin B, and four non-WT for azoles. Non-WT were not encountered for caspofungin. Non-Aspergillus isolates in New Zealand have susceptibility patterns similar to those reported elsewhere. In contrast to a growing number of other countries, azole resistance was rare in A. fumigatus sensu stricto. Non-WT isolates were uncommon. The results provide a baseline for monitoring emerging antifungal resistance in New Zealand and support current Australasian treatment guidelines for invasive fungal infections.

This paper aimed at studying a novel high biomass strain (HBS) of marine protist, Thraustochytrium striatum, for lignin valorization to lipids and carotenoids. In the screening of 15 aromatic compounds, T. striatum HBS can utilize most compounds while achieving the best growth on 3,4-dihydroxybenzoic acid (3,4-DHBA) and 4-hydroxybenzoic acid (4-HBA). The maximum cell mass concentration reached 2−3 g/L under 5 g/L of 3,4-DHBA or 2 g/L of 4-HBA, which was comparable to that under equivalent concentration of glucose. The long-chain fatty acids content was 13 % and 7 % with 3,4-DHBA and 4-HBA, respectively. The adoption of fed-batch fermentation mode improved the degradation of carbon source and prevented the inhibitory effect caused by overloading of aromatic compounds. Both final cellular fatty acids and carotenoids contents were doubled in the fermentation of 3,4-DHBA. T. striatum HBS exhibited limited lignin depolymerization (∼24 %) ability on technical lignins.

There is a need for high‐performance applications for terephthalic acid (TPA) polyesters with high heat resistance, impact toughness, and optical clarity. Bisphenol A (BPA) based polycarbonates and polyarylates have such properties, but BPA is an endocrine disruptor. Therefore, new TPA polyesters that are less hazardous to health and the environment are becoming popular. Tetramethylcyclobutanediol (TMCD) is a difunctional monomer that can be polymerized with TPA and other diols to yield copolyesters with superior properties to conventional TPA polyesters. It has a cyclobutyl ring that makes it more rigid than cyclohexanedimethanol (CHDM) and EG. Thus, TMCD containing TPA copolyesters can have high heat resistance and impact strength. TPA can be made from abundantly available upcycled polyethylene terephthalate (PET). Therefore, this review discusses the synthesis of monomers and copolyesters, the impact of diol composition on material properties, molecular weight, effects of photodegradation, health safety, and substitution of cyclobutane diols for future polyesters., High‐performance plastics: Tetramethylcyclobutanediol containing terephthalic acid based copolyesters can give high heat resistance and impact toughness which are useful in the manufacturing of high‐performance plastic parts.

Sterile filtration is an integral step in the manufacturing process of biological therapeutics. Protein adsorption to the surface of the filter is an unfortunate, common occurrence that can result in manufacturing difficulties, such as filter fouling or product loss. Although many filters have surface modifications to minimize adsorption, under certain conditions binding can still occur. We observed the loss of high molecular weight species (HMWS) during sterile filtration of eight different therapeutic monoclonal antibodies formulated at low protein concentrations across a commonly used hydrophilic polyvinylidene fluoride or polyvinylidene difluoride (PVDF) filter membrane. The protein absorption was specific to HMWS, and each antibody exhibited different degrees of filter adsorption. Debye screening length parameters of the solution (e.g. ionic strength) were adjusted, and influenced the amount of HMWS lost during filtration. Additionally, HMWS of a representative antibody (mAb1) were observed to be more positively charged than other size variants by ion-exchange chromatography. From these results, it is concluded that this HMWS loss is due to electrostatic interactions between HMWS and the filter surface. This adsorption can be reduced by increasing the ionic strength of the buffer matrix, demonstrating the influence of the Debye screening length in the filtration of low concentration proteins.

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.

In nature, cellulose nanofibers form hierarchical structures across multiple length scales to achieve high-performance properties and different functionalities. Cellulose nanofibers, which are separated from plants or synthesized biologically, are being extensively investigated and processed into different materials owing to their good properties. The alignment of cellulose nanofibers is reported to significantly influence the performance of cellulose nanofiber-based materials. The alignment of cellulose nanofibers can bridge the nanoscale and macroscale, bringing enhanced nanoscale properties to high-performance macroscale materials. However, compared with extensive reviews on the alignment of cellulose nanocrystals, reviews focusing on cellulose nanofibers are seldom reported, possibly because of the challenge of aligning cellulose nanofibers. In this review, the alignment of cellulose nanofibers, including cellulose nanofibrils and bacterial cellulose, is extensively discussed from different aspects of the driving force, evaluation, strategies, properties, and applications. Future perspectives on challenges and opportunities in cellulose nanofiber alignment are also briefly highlighted.

Purpose Carbohydrate (CHO) restriction could be a potent metabolic regulator of endurance exercise-induced muscle adaptations. Here, we determined whether post-exercise CHO restriction following strenuous exercise combining continuous cycling exercise (CCE) and sprint interval exercise could affect the gene expression related to mitochondrial biogenesis and oxidative metabolism in human skeletal muscle. Methods In a randomized cross-over design, 8 recreationally active males performed two cycling exercise sessions separated by 4 weeks. Each session consisted of 60-min CCE and six 30-s all-out sprints, which was followed by ingestion of either a CHO or placebo beverage in the post-exercise recovery period. Muscle glycogen concentration and the mRNA levels of several genes related to mitochondrial biogenesis and oxidative metabolism were determined before, immediately after, and at 3 h after exercise. Results Compared to pre-exercise, strenuous cycling led to a severe muscle glycogen depletion (> 90%) and induced a large increase in PGC1A and PDK4 mRNA levels (~ 20-fold and ~ 10-fold, respectively) during the acute recovery period in both trials. The abundance of the other transcripts was not changed or was only moderately increased during this period. CHO restriction during the 3-h post-exercise period blunted muscle glycogen resynthesis but did not increase the mRNA levels of genes associated with muscle adaptation to endurance exercise, as compared with abundant post-exercise CHO consumption. Conclusion CHO restriction after a glycogen-depleting and metabolically-demanding cycling session is not effective for increasing the acute mRNA levels of genes involved in mitochondrial biogenesis and oxidative metabolism in human skeletal muscle.

Modification of lignin with poly(e-caprolactone) is a promising approach to valorize industrial low-value lignins and to advance the bioeconomy. We have synthesized lignin grafted poly(e-caprolactone) (lignin-g-PCL) copolymers via ring-opening polymerization of e-caprolactone with different types of lignins of varying botanical sources (G-type pine lignin, S/G-type poplar lignin, and C-type Vanilla seeds lignin) and lignin extraction methods (Kraft and ethanol organosolv pulping). The lignin-g-PCL copolymer showed remarkably improved compatibility and dispersion in acetone, chloroform, and toluene in comparison to non-modified lignins. The structure and thermal properties of the lignin-g-PCL were investigated using Fourier-transform infrared spectroscopy (FTIR), 31P nuclear magnetic resonance (NMR), 2D heteronuclear single quantum correlation (HSQC) NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). We have found that all the technical lignins were reactive to the copolymerization reaction regardless of their plant source and isolation methods. The molecular weights of the synthesized lignin-g-PCL copolymers were positively correlated with the content of aliphatic lignin hydroxyls, suggesting that the copolymerization reaction tends to occur preferentially at the aliphatic hydroxyls rather than the phenolic hydroxyls of lignin. Thermal analyses of the lignin-g-PCL copolymers were studied, and in general, a reduction of melting temperature and crystallinity percentage in comparison to the neat PCL was observed. However, the thermal behavior of lignin-g-PCL copolymers varied depending on the lignin feedstocks employed in the copolymerization reaction.

Biological lignin valorization represents an emerging green approach to upgrade lignin for sustainable and economic biorefineries. However, lignin generally exhibits poor water solubility and inhomogeneous distribution in an aqueous medium, significantly limiting its bioconversion efficiency. Herein, we develop a novel alkali sterilization strategy to effectively enhance the dispersion and fermentation performance of lignin substrates. The colloidal particle size and molecular structure variations of lignin during the sterilization were thoroughly investigated to reveal the mechanisms of enhanced fermentation performance. Results showed that alkali sterilization achieved a completely aseptic effect when mixing lignin medium at an initial pH of 12.7 for 24 h. Dynamic light scattering (DLS) analysis demonstrated that the hydrodynamic volume of colloidal lignin particles decreased by 96.3% by alkali sterilization compared with the conventional thermal sterilization. Moreover, lignin characterizations by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) suggested that alkali sterilization modified the lignin molecular structure by generating 50% more hydrophilic carboxyl groups, reducing the weight-average molecular weight (Mw) by 23.0%, and narrowing the molar-mass dispersity (ĐM) by 23.8%. The generation of lignin substrates with more uniform distribution and lower molecular weight improved Rhodococcus opacus PD630 cell growth and metabolism. Microbial cell amount, lignin degradation, and lipid production in alkali sterilized medium increased by 309%, 30.3%, and 48.3%, respectively, compared to those in thermally sterilized medium. These results clearly demonstrated that alkali sterilization dramatically improved the lignin bioconversion performance. This work presents a facile and effective sterilization strategy to overcome inhomogeneous lignin distribution in aqueous fermentation media, showing great potentials as a platform technique for promoting biological lignin valorization.

Lignin has been explored extensively as a renewable precursor for carbon materials, considering its abundance as a major component of plant cell walls and its sustainability as a byproduct of both lignocellulosic biorefinery and the paper-making industry. Despite the extensive efforts to define the process–property relationship, it remains largely unknown how lignin biosynthesis and its chemistry would impact the resultant carbon fiber properties, for both mechanical and electroconductive performances. Such inadequate understanding fundamentally limits feedstock design and selection to improve carbon fiber properties toward broader commercial applications. Using lignin from a broad range of biomass feedstocks for carbon fiber manufacturing, we have fundamentally explored the structure–function relationship between lignin chemistry and carbon fiber performance. Specifically, lignin extracted from hardwood (sugar maple), softwood (loblolly pine and red cedar), and herbaceous plants (corn stover and switchgrass) was used for carbon fiber manufacturing, considering the very different lignin structures from these feedstocks. Linear regression models were established to define the relationship between carbon fiber mechanical properties and lignin structural characteristics. The results highlighted that the content of β-O-4 linkages correlates significantly with the tensile strength and elastic modulus of lignin carbon fibers, indicating that more linear β-O-4 linkages would promote the carbon fiber mechanical performance. Moreover, electroconductive properties are essential for broader energy device application of lignin-based carbon fibers, yet the mechanisms controlling their electroconductivity are largely unknown. We hereby demonstrated that a higher β-O-4 content also promotes the electroconductivity of lignin carbon fibers. Microstructure analysis further revealed that the crystallite size and content of the pre-graphitic turbostratic carbon structure in lignin-based carbon fibers were enhanced as the β-O-4 linkages increased. The content of β-O-4 linkages has shown a strong correlation with the crystallite content in a linear regression model. This study thus revealed the underlying mechanisms regarding how the lignin structure in planta defines the resultant carbon fiber properties. Moreover, the study also highlighted the correlation between the mechanical and electroconductive properties of lignin-based carbon fibers, both of which were defined by the lignin structure.

Supercritical ethanol liquefaction of teak wood was carried out at 300 °C for 30 min without and with the use of Mg(ClO4)2, HClO4, and HClO4/Mg(ClO4)2 at various loadings (2–10 mmol). The bio-oil yield from the non-catalytic supercritical ethanol liquefaction of teak wood was ∼41 wt%. The highest bio-oil yield (∼58.2 wt%) was obtained with the catalytic run using 2 mmol of Mg(ClO4)2. In the catalyzed trials, with the use of either Mg(ClO4)2 or HClO4, an increase in catalyst amounts resulted in a decrease in bio-oil yields. There was no clear trend for the use of co-catalysts. A degree of de-oxygenation was observed with the use of the catalysts studied. The O/C atomic ratio of the bio-oil from the non-catalytic was 0.44. The O/C atomic ratios in the bio-oil produced from catalytic runs ranged from 0.25 to 0.38. In the bio-oil from the non-catalytic run, the major compound was phenolic species, whereas esters were dominant in the bio-oils from the catalytic runs. The type of catalyst and its amount had significant effects on the product distributions and compositions. The prominent ester compounds were ethyl lactate and ethyl levulinate. The highest relative yield of ethyl levulinate was 49.1% and obtained with the use of the Mg(ClO4)2/HClO4 (2 mmol : 10 mmol) catalyst. The heating values of the bio-oils from catalytic runs were higher than that of the non-catalytic run. The highest heating value of 31.21 MJ kg−1 was obtained with the Mg(ClO4)2/HClO4 (2 mmol : 10 mmol) catalyst.

To explore the effect of lignin composition on cellulase adsorption, dehydrogenation polymers (DHPs) were prepared from p-glucocoumaryl alcohol/coniferin/syringin, giving rise to H-DHP, G-DHP, and S-DHP, respectively. The structures of DHPs were thoroughly characterized and compared by GPC and NMR techniques, and the Langmuir isotherm protocol was applied to determine the cellulase adsorption behaviors of these different types of DHPs. The adsorption study indicated that the binding strength between the DHPs and cellulase varied in the following order: G-DHP > H-DHP > S-DHP. The inhibition of different types of DHPs on enzymatic hydrolysis of cellulose was in the same order as the cellulase adsorption, indicating that non-productive adsorption was the main way to influence cellulase. The correlation analysis results showed a positive association between the phenolic hydroxyl group content in DHPs and their maximum adsorption capacity toward enzymes. A negative correlation between the PDI and binding strength was also observed. It was also found that the adsorbed cellulase could be desorbed and retained normal enzyme activity, and so it was presumed that DHPs and cellulase were mainly linked by physisorption such as hydrogen bonding. This study clearly showed that the composition of lignin had a great impact on cellulase, and that G-type lignin exhibited the most detrimental effect. The results could provide useful information on the mechanism of cellulase adsorption onto lignin using DHPs as lignin model compounds.

The major plastic wastes are always mixtures, which are difficult to separate to treat in practice. Because of some possible cross-reactions, the degradation behaviors of plastics could not be mathematically represented by a simple addition of each polymer according to their proportions. This work examines supercritical water (scH2O) to liquefy poly-ethylene and poly-propylene mixtures into an oil with special interest in the oil quality and positive effect. Linear low-density polyethylene (LLDPE) and polypropylene (PP) were chosen as parent materials because of their high proportions in plastic wastes. The results show that a high conversion rate of around 99.75% was achieved with as high as 90.7 wt% oil yield without additional catalysts or hydrogen. The scH2O co-liquefaction of the LLDPE/PP mixture was different from that of the single polymer along with an improvement in the oil yield. Cyclic hydrocarbon (i.e., cyclic) generation was promoted while the production of paraffins was hindered in scH2O co-liquefaction using a mixture of LLDPE/PP. TGA reveals that the scH2O co-liquefaction of LLDPE/PP mixtures generated more diesel and lubricant oils and less gasoline and (jet fuel + light diesel) oils, thus slightly lowering the oil quality. Overall, the supercritical fluid technology was a powerful and promising means to liquefy mixed plastic wastes into oil at a high conversion rate free of catalysts or hydrogen.

The SiO2/Al2O3 mole ratio, pore size, and acid sites are the key parameters of zeolite’s activity in lignin pyrolysis. In this study, the comparison of individual Y and M zeolites, the combined ‘Y + M’ sample after regeneration, and their effect on lignin pyrolysis were studied in five cycles (regeneration and reuse). The results were explained using Brunauer, Emmet, and Teller (BET), micropore surface area (MSA), and total acid sites (TAS) analyses. In comparison with the individual Y or M zeolite sample, the consistent higher catalytic activities of the combined ‘Y + M’ sample in repeated cycles were observed. Pyrolysis heavy oils were characterized by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The NMR analyses revealed that with increased zeolite regeneration cycles, p-hydroxy phenyl and methoxyl groups increased. Decreases in guaiacyl phenolic hydroxyl were less for the combined ‘Y + M’ sample than the individual Y and M zeolites. Lower weight average (Mw) of heavy oil for the combined ‘Y + M’ sample indicated the enhanced cleavage of lignin structures in pyrolysis. These results support the higher catalytic activity of regenerated zeolites for the combined ‘Y + M’ sample compared with individual Y and M zeolites due to the improved MSA and TAS.

Dihydroxyacetone (DHA) and glyceraldehyde (GA)—the simplest monosaccharides in nature—are both essential building blocks in organic synthesis. There have been detailed investigations on the selecti...

Fibrillated cellulose has been frequently used for making nanopapers and thin films. However, limited work has been carried out in the construction of such materials using native lignocellulosic biomass. Making papers from fibrillated biomass allows complete utilization of whole plant material and may reduce chemical and energy consumption. Ultra-friction grinding was used to directly fibrillate knife-milled poplar into micro- to nano-sized biomass fibers. Papers were made using the fibrillated biomass containing nanofibrillated biomass and their mechanical properties were tested. Biomass papers made via press-drying had higher tensile strength than papers made by air-drying. A higher press-drying temperature of 180 °C produced stronger papers than at 150 °C. Guar gum substantially increased the strength of the press-dried papers in comparison to cationic starch. Press-drying increased the thermogravimetric peak decomposition temperature by 13 °C in comparison to air-drying.

As a highly abundant renewable carbon source, lignin can be converted to a variety of advanced carbon materials with tailorable properties through slow pyrolysis. In this study, slow pyrolysis of kraft lignin, for the first time, was investigated with a commercial pyrolysis–gas chromatography−mass spectrometry (Py-GC-MS) system through evolved gas analysis-MS (EGA-MS) and heart-cutting-GC-MS (HC-GC-MS) analyses. These analyses allow recovery and examination of the multi-phased gas products generated from thermal decomposition of lignin during slow pyrolysis over long time course thus making it possible to link pyrolysis chemistry and carbon material properties. The overall product distributions, including volatiles and solid product were quantitatively tracked at different heating rates (2, 20, 40 ℃/min) and different temperature regions (100-200, 200-300 and 300-600 ℃). Solid residues were further characterized using a suite of analytical tools, in correlation with the investigation of formation mechanisms of volatiles to reveal the reaction chemistry of lignin during slow pyrolysis, and to determine the morphology, pore structure, and interfacial chemical properties. This study provides critical insights into the slow pyrolysis chemistry of lignin and the properties of the resulting carbon material. These results will facilitate a better design and control of the lignin slow pyrolysis process for synthesizing functional carbon materials.

Prion disease is a rapidly progressive neurodegenerative disorder caused by misfolding and aggregation of the prion protein (PrP), and there are currently no therapeutic options. PrP ligands could theoretically antagonize prion formation by protecting the native protein from misfolding or by targeting it for degradation, but no validated small-molecule binders have been discovered to date. We deployed a variety of screening methods in an effort to discover binders of PrP, including 19F-observed and saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy, differential scanning fluorimetry (DSF), DNA-encoded library selection, and in silico screening. A single benzimidazole compound was confirmed in concentration-response, but affinity was very weak (Kd > 1 mM), and it could not be advanced further. The exceptionally low hit rate observed here suggests that PrP is a difficult target for small-molecule binders. While orthogonal binder discovery methods could yield high affinity compounds, non-small-molecule modalities may offer independent paths forward against prion disease.

Members of the genus Populus (i.e., cottonwood, hybrid poplar) represent a promising source of lignocellulosic biomass for biofuels. However, one of the major factors negatively affecting poplar's efficient conversion to biofuel is the inherent recalcitrance to enzymatic saccharification due to cell wall components such as lignin. To this effect, there have been efforts to modify gene expression to reduce biomass recalcitrance by changing cell wall properties. Here, we review recent genetic modifications of poplar that led to change cell wall properties and the resulting effects on subsequent pretreatment efficacy and saccharification. Although genetic engineering's impacts on cell wall properties are not fully predictable, recent studies have shown promising improvement in the biological conversion of transgenic poplar to biofuels.

We used small-angle neutron scattering (SANS) and wide-angle X-ray scattering (WAXS) to study two Populus trichocarpa variants, GW-11012 and BESC-316, with lignin contents of 17.8 and 23.2%, respec...

Deep eutectic solvents (DESs) are effective solvents for biomass conversion and have been proposed as alternatives to ionic liquids (ILs). Herein, we first report an effective pretreatment of woody...

Significance The use of plant biomass for the production of fuels and chemicals is of critical economic and environmental importance, but has posed a formidable challenge, due to the recalcitrance of biomass to deconstruction. We report direct experimental and computational evidence of a simple physical chemical principle that explains the success of mixing an organic cosolvent, tetrahydrofuran, with water to overcome this recalcitrance. The hydrophilic and hydrophobic biomass surfaces are solvated by single-component nanoclusters of complementary polarity. This principle can serve as a guide for designing even more effective technologies for solubilizing and fractionating biomass. The results further highlight the role of nanoscale fluctuations of molecular solvents in driving changes in the structure of the solutes., A particularly promising approach to deconstructing and fractionating lignocellulosic biomass to produce green renewable fuels and high-value chemicals pretreats the biomass with organic solvents in aqueous solution. Here, neutron scattering and molecular-dynamics simulations reveal the temperature-dependent morphological changes in poplar wood biomass during tetrahydrofuran (THF):water pretreatment and provide a mechanism by which the solvent components drive efficient biomass breakdown. Whereas lignin dissociates over a wide temperature range (>25 °C) cellulose disruption occurs only above 150 °C. Neutron scattering with contrast variation provides direct evidence for the formation of THF-rich nanoclusters (Rg ∼ 0.5 nm) on the nonpolar cellulose surfaces and on hydrophobic lignin, and equivalent water-rich nanoclusters on polar cellulose surfaces. The disassembly of the amphiphilic biomass is thus enabled through the local demixing of highly functional cosolvents, THF and water, which preferentially solvate specific biomass surfaces so as to match the local solute polarity. A multiscale description of the efficiency of THF:water pretreatment is provided: matching polarity at the atomic scale prevents lignin aggregation and disrupts cellulose, leading to improvements in deconstruction at the macroscopic scale.

Aging and associated progressive arterial stiffening are both important predictors for the development of cardiovascular diseases. Recent evidence showed that autophagy, a catabolic cellular mechanism responsible for nutrient recycling, plays a major role in the physiology of vascular cells such as endothelial cells and vascular smooth muscle cells (VSMCs). Moreover, several autophagy inducing compounds are effective in treating arterial stiffness. Yet, a direct link between VSMC autophagy and arterial stiffness remains largely unidentified. Therefore, we investigated the effects of a VSMC-specific deletion of the essential autophagy-related gene Atg7 in young mice (3.5 months) (Atg7F/F SM22α-Cre+ mice) on the biomechanical properties of the aorta, using an in-house developed Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC). Aortic segments of Atg7F/F SM22α-Cre+ mice displayed attenuated compliance and higher arterial stiffness, which was more evident at higher distention pressures. Passive aortic wall remodeling, rather than differences in VSMC tone, is responsible for these phenomena, since differences in compliance and stiffness between Atg7+/+ SM22α-Cre+ and Atg7F/F SM22α-Cre+ aortas were more pronounced when VSMCs were completely relaxed by the addition of exogenous nitric oxide. These observations are supported by histological data showing a 13% increase in medial wall thickness and a 14% decrease in elastin along with elevated elastin fragmentation. In addition, expression of the calcium-binding protein S100A4, which is linked to matrix remodeling, was elevated in aortic segments of Atg7F/F SM22α-Cre+ mice. Overall, these findings illustrate that autophagy exerts a crucial role in defining arterial wall compliance.

Technical lignin extracted from pulping and biorefining processes provides a class of complex and polydisperse phenolic polymers. Preparation of lignin with lower structural complexity and polydisp...

Production of deuterated cellulose is important from both theoretical and practical perspectives. In this study, cellulose fibers of cotton and Tencel fibers with exchange-resistant deuterium incorporation were prepared by hydrogen–deuterium exchange treatment. The effect of the micro-structure of cellulose crystallinity index as well as the reaction conditions including catalyst, reaction time, and temperature on the exchange-resistant deuterium incorporation process are reported. The ability of deuterated cellulose fibers to resist protium-exchange during H2O washing was also explored. The results found that higher crystallinity index is beneficial to stabilize the deuteration of cellulose fibers. Furthermore, alkaline catalysts such as sodium hydroxide or potassium carbonate and higher exchange temperature as well as longer reaction time contribute significantly to the stabilization of deuterium incorporation in the deuterated cellulose fibers. These observations revealed that the hydrogen–deuterium exchange treatment is effective to obtain exchange-resistant deuterium incorporated cellulose fibers. In addition, cotton fibers with several deuteration levels were produced and could be considered for the study of deuterium effect on cellulose properties.

Bamboo represents a family of highly lignified biomass with significant resistance to cellulolytic enzyme degradation, and typically, a severe thermochemical pretreatment is needed to overcome its ...

Ozone is one of the six “criteria” pollutants identified by the U.S. Clean Air Act Amendment of 1970 as particularly harmful to human health. Concentrations have decreased markedly across the United States over the past 50 years in response to regulatory efforts, but continuing research on its deleterious effects have spurred further reductions in the legal threshold. The South Coast and San Joaquin Valley Air Basins of California remain the only two “extreme” ozone nonattainment areas in the United States. Further reductions of ozone in the West are complicated by significant background concentrations whose relative importance increases as domestic anthropogenic contributions decline and the national standards continue to be lowered. These background concentrations derive largely from uncontrollable sources including stratospheric intrusions, wildfires, and intercontinental transport. Taken together the exogenous sources complicate regulatory strategies and necessitate a much more precise understanding of the timing and magnitude of their contributions to regional air pollution. The California Baseline Ozone Transport Study was a field campaign coordinated across Northern and Central California during spring and summer 2016 aimed at observing daily variations in the ozone columns crossing the North American coastline, as well as the modification of the ozone layering downwind across the mountainous topography of California to better understand the impacts of background ozone on surface air quality in complex terrain.

Alkaline induced deacetylation of the hemicellulose combined with subsequent mechanical refining enhanced the enzyme-mediated hydrolysis of pretreated corn stover. The addition of either NaOH (80 °...

The objective of this research was to investigate the presence of residual lignin in cellulose fibers on the efficiency and energy consumption during nanofibers processing. Four kinds of lignin-containing cellulose nanofibers (LCNFs) from switchgrass, yellow poplar, hybrid poplar, and pine, respectively, were isolated via organosolv fractionation coupling mechanical grinding. Nanofibrils were observed after organosolv fractionation. The details of their morphological features, chemical structures, water retention value (WRV), and thermal degradation characteristics were revealed and compared. Mean diameters of nanofibers separated from switchgrass, yellow poplar, hybrid poplar, and pine were 27.9 nm, 25.4 nm, 24.6 nm, and 21.5 nm, respectively. The presence of lignin for the four types of LCNFs led to a decrease in energy consumption and an increase in WRV, among which pine nanofibers show the best with an average energy consumption of 0.511 kWh/kg and a WRV of 537%. It was also demonstrated that increasing lignin content for LCNFs could contribute to the sample’s thermal stability. In conclusion, exact benefits of residual lignin for nanofiber will facilitate its preparation process and extend its application.

Lignin-derived chemicals and fuel products have received much attention in the context of bio-refinery. In this study we prepared and characterized various lignin samples from black liquor (BL), a major byproduct from the pulp and paper manufacturing processes, and studied the pyrolysis behaviors of these isolated lignin samples at 600 °C under a N2 atmosphere. Three lignin samples were isolated from the Kraft pulping BL of Loblolly pine linerboard grade process (KL, obtained by direct evaporation; L10, obtained by precipitation at pH 10; L3, obtained by precipitation at pH 3), while another three were from the Kraft pulping BL of Loblolly pine bleach grade process (KB, B10, B3). The inorganic elements present in lignin samples were analyzed using an inductively coupled plasma (ICP) analyzer. The KL and KB samples contained a larger amount of inorganic elements, especially Na and S, than did the other lignin samples. Owing to large quantities of inorganic elements, the ash contents in KL and KB were highe...

How to effectively remove toxic dyes from the industrial wastewater using a green low-cost lignocellulose-based adsorbent, such as lignin, has become a topic of great interest but remains quite challenging. In this study, cosolvent-enhanced lignocellulosic fractionation (CELF) pretreatment and Mannich reaction were combined to generate an aminated CELF lignin which is subsequently applied for removal of methylene blue and direct blue (DB) 1 dye from aqueous solution. 31P NMR was used to track the degree of amination, and an orthogonal design was applied to determine the relationship between the extent of amination and reaction parameters. The physicochemical, morphological, and thermal properties of the aminated CELF lignin were characterized to confirm the successful grafting of diethylenetriamine onto the lignin. The aminated CELF lignin proved to be an effective azo dye-adsorbent, demonstrating considerably enhanced dye decolorization, especially toward DB 1 dye (>90%). It had a maximum adsorption capacity of DB 1 dye of 502.7 mg/g, and the kinetic study suggested the adsorption process conformed to a pseudo-second-order kinetic model. The isotherm results also showed that the modified lignin-based adsorbent exhibited monolayer adsorption. The adsorbent properties were mainly attributed to the incorporated amine functionalities as well as the increased specific surface area of the aminated CELF lignin.

Black liquor that contains various phenolic compounds from lignin solubilization has been the main byproduct of alkaline pretreatment of lignocellulosic biomass in the biorefinery. In this study, black liquor from alkaline pretreatment of corn stover was used as a sole carbon source for the cultivation of a marine protist, Thraustochytrium striatum. It was found that this strain can grow on black liquor and accumulate valuable products (e.g., fatty acids and carotenoids) simultaneously. Under optimal conditions (pH = 7 and NH4Cl = 2 g/L), the cell mass concentration reached 5.2 g/L with total aromatics decreased from 8.18 to 3.09 g/L within 7 day incubation. Fed-batch cultivation was adopted to increase the contents of total fatty acids and carotenoids to 13% and 0.24 mg/g dry cell mass, respectively. Although various compounds such as sugars and organic acids were detected in black liquor and consumed during microbial fermentation as carbon sources, lignin-derived compounds were identified as the major s...

The enzyme MiaB catalyzes the attachment of a methylthio (-SCH3) group at the C2 position of N6-(isopentenyl)adenosine (i6A) in the final step of the biosynthesis of the hypermodified tRNA nucleotide 2-methythio-N6-(isopentenyl)adenosine (ms2i6A). MiaB belongs to the expanding subgroup of enzymes of the radical S-adenosylmethionine (SAM) superfamily that harbor one or more auxiliary [4Fe-4S] clusters in addition to the [4Fe-4S] cluster that all family members require for the reductive cleavage of SAM to afford the common 5'-deoxyadenosyl 5'-radical (5'-dA•) intermediate. While the role of the radical SAM cluster in generating the 5'-dA• is well understood, the detailed role of the auxiliary cluster, which is essential for MiaB catalysis, remains unclear. It has been proposed that the auxiliary cluster may serve as a coordination site for exogenously derived sulfur destined for attachment to the substrate or that the cluster itself provides the sulfur atom and is sacrificed during turnover. In this work, we report spectroscopic and biochemical evidence that the auxiliary [4Fe-4S]2+ cluster in Bacteroides thetaiotaomicron (Bt) MiaB is converted to a [3Fe-4S]0-like cluster during the methylation step of catalysis. Mossbauer characterization of the MiaB [3Fe-4S]0-like cluster revealed unusual spectroscopic properties compared to those of other well-characterized cuboidal [3Fe-4S]0 clusters. Specifically, the Fe sites of the mixed-valent moiety do not have identical Mossbauer parameters. Our results support a mechanism where the auxiliary [4Fe-4S] cluster is the direct sulfur source during catalysis.

To understand the influence of lignin characteristics on their antioxidant activities, lignins were isolated from Broussonetia papyrifera by organosolv pretreatment at different temperatures. The physicochemical features of the lignins were investigated by GPC, 31P NMR and 2D HSQC NMR analyses. An increase of organosolv pretreatment temperature resulted in a decrease of Mw and an increase of the phenolic hydroxyl group content in the isolated lignin. The lignins extracted at higher organosolv pretreatment temperature showed higher antioxidant activity according to the IC50 determined using DPPH and ABTS. The correlations between the physicochemical properties of organosolv lignins and their antioxidant activities were studied. The contents of phenolic hydroxyl groups, especially syringyl and guaiacyl, and double bonds in the Cα position had positive effects on the antioxidant activity of the lignins. On the other hand, Mw and aliphatic hydroxyl groups of the lignins exhibited negative correlations with the antioxidant activity.

Despite only recently becoming available in the quantities required for solvent usage, the cellulose-derived solvent, named Cyrene, has gained significant attention in green chemistry in recent years. To fulfill the sustainability criteria of future biorefineries, a novel renewable biomass pretreatment using Cyrene and water was developed for the first time. Results showed that Cyrene has high potential as a green pretreatment solvent in terms of lignin fractionation/recovery and sugar release in the follow-up enzymatic hydrolysis. The mechanism of this pretreatment was revealed by investigating the structural characteristics of pretreated biomass, and the recovered lignin was also fully characterized to assess its valorization potential. Results indicated that Cyrene pretreatment could be performed at a mild condition (120 °C) to reduce the lignin condensation and the cleavage of β-O-4 linkages without compromising lignin removal and the following sugar platform. The successful utilization of this cellulose-derived solvent in pretreatment will further contribute to the realization of a “closed-loop” biorefinery process.

Three-dimensional (3D) printing is an additive manufacturing technique with a wide range of 3D structure fabrication and minimal waste generation. Recently, lignocellulosic biomass and its derivatives have been used in 3D printing due to their renewable nature and sustainability. This review provides a summary of the development of different types of biomass and its components such as cellulose and lignin in 3D printing, brief data analysis and introduction to characterization methods of the 3D printed composites. Mechanical properties such as tensile properties, Izod impact properties, and flexural properties, thermal properties and morphological properties of 3D-printed composites are discussed. In addition, other available characterization methods of 3D-printed composites are reported. The future direction of biomass and its derivatives in the field of 3D printing is also discussed.

A combination of thermochemical pretreatment and biological digestion technologies is usually required to overcome lignocellulosic recalcitrance and accomplish effective biomass deconstruction. This study is aimed at understanding switchgrass breakdown by hydrothermal, dilute acid, dilute alkali, and co-solvent enhanced lignocellulosic fractionation (CELF) pretreatments followed by application of traditional fungal enzymatic hydrolysis (EH) and Clostridium thermocellum consolidated bioprocessing (CBP) to the resulting solids. Unpretreated and pretreated switchgrass and their EH and CBP residues were characterized by a suite of analytical techniques to understand structural changes that occurred during deconstruction. CELF pretreated solids showed the highest accessibility and digestibility by both EH and CBP followed by dilute alkali and then dilute acid/hydrothermal pretreated solids. Lignin removal from biomass had a more positive impact on substrate accessibility and digestibility than did xylan removal, while xyloglucan removal by pretreatment appeared essential for cellulose digestion by fungal enzymes. The extent of CBP digestion of cellulose and non-cellulosic glycans was larger than that by EH. Unlike dilute alkali pretreatment, cellulose crystallinity increased for acid-based pretreatments in the following order: hydrothermal, dilute acid, and CELF. Acid-based pretreatments also substantially reduced cellulose degree of polymerization. All thermochemical and biological digestion approaches increased syringyl to guaiacyl lignin (S/G) ratio and reduced β-O-4 lignin interunit linkage and hydroxycinnamates content from levels in unpretreated switchgrass. The substantial increase in S/G ratio after hydrothermal and dilute alkali preatreatments suggested that high temperatures or alkali removed a large portion of G lignin from switchgrass.

Several deep eutectic solvents (DESs) have been demonstrated to be highly effective for lignocellulosic biomass pretreatment, combining the advantages of simple synthesis, relatively low chemical cost and better biocompatibility. However, low biomass loading that is usually involved with DES pretreatment hinders its practical use. In this study, a twin-screw extruder was used for pretreating biomass sorghum bagasse at solid loadings up to 50%, mediated by a neutral-pH DES, choline chloride : glycerol (ChCl : Gly). This continuous extrusion process led to high glucose and xylose yields of >85% from enzymatic saccharification of the pretreated sorghum. A combination of microscopic, spectroscopic, and X-ray diffraction analyses demonstrate a high degree of defibration and disruption of the biomass cell wall structures; however, little or no change in chemical compositions. Further results from gel permeation chromatographic (GPC) and nuclear magnetic resonance (NMR) spectroscopic analyses indicate that ChCl : Gly-mediated extrusion preserved the basic lignin structural characteristics with no significant differences between extruded biomass at a solid loading of 30% and 50%. This study demonstrates the potential of DES-mediated extrusion as a highly effective continuous high-solid biomass pretreatment technology for industrially relevant applications.

Ball milling is used for size reduction of biomass for isolating lignin. However, it is known that it can lead to some structural alteration of lignin. Fibrillation using ultrafriction grinding is a newer size reduction technology which was applied to poplar for isolating cellulolytic enzyme lignin. Compositional analysis of poplar, enzymatic hydrolysis yield, water retention value, lignin yield, lignin structural characterization, and lignin molecular weight analysis were carried out to compare lignin isolated from fibrillated and ball milled poplar. By using fibrillation instead of planetary ball milling for size reduction of poplar, higher β-O-4′ linkage content, lignin yield, and molecular weight were obtained. Replacing ball milling with fibrillation for size reduction allows recovery of lignin whose structure is closer to that of lignin in biomass.

Enhancement of lignin reactivity plays a critical role in the chemical modification of lignin. In the current study, a simple, green, and effective method, of ozone oxidation, was developed to impr...

Pretreatment is commonly used to reduce recalcitrance of the lignin-carbohydrate matrix. In this study, leading pretreatment technologies, including dilute sulfuric acid, liquid hot water, alkaline, and organosolv pretreatments, were applied to the selected Populus trichocarpa genotype with relatively low lignin content to elucidate cellulose physicochemical property changes and digestibility-related factors. Pretreated Populus trichocarpa (BESC 131) exhibited higher accessibility and glucose yield than the untreated biomass. Chemical composition and Fourier transform infrared (FTIR) analysis results revealed that hemicellulose and lignin were removed to a varying extent depending on the pretreatment techniques applied. The degree of polymerization of the cellulose was decreased to the largest extent after dilute acid pretreatment, followed by organosolv, alkaline, and liquid hot water pretreatments. Cellulose crystallinity index was slightly changed after the pretreatments; however, its differences were not remarkable between those pretreatment techniques. Among four different pretreatments, organosolv was the most effective pretreatment technology in terms of sugar release, which was three times higher than that of the untreated native biomass. Among all of the tested cell wall traits, the lignin content of Populus trichocarpa was the most remarkable feature associated with glucose release, though Populus trichocarpa recalcitrance was not solely dependent on any single factor.