8 results on '"Combined pretreatment"'
Search Results
2. Understanding the synergistic effect and the main factors influencing the enzymatic hydrolyzability of corn stover at low enzyme loading by hydrothermal and/or ultrafine grinding pretreatment.
- Author
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Zhang, Haiyan, Li, Junbao, Huang, Guangqun, Yang, Zengling, and Han, Lujia
- Subjects
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HYDROTHERMAL alteration , *MICROSTRUCTURE , *MICROPHYSICS , *HYDROLYSIS , *PARTICLE size determination - Abstract
A thorough assessment of the microstructural changes and synergistic effects of hydrothermal and/or ultrafine grinding pretreatment on the subsequent enzymatic hydrolysis of corn stover was performed in this study. The mechanism of pretreatment was elucidated by characterizing the particle size, specific surface area (SSA), pore volume (PV), average pore size, cellulose crystallinity (CrI) and surface morphology of the pretreated samples. In addition, the underlying relationships between the structural parameters and final glucose yields were elucidated, and the relative significance of the factors influencing enzymatic hydrolyzability were assessed by principal component analysis (PCA). Hydrothermal pretreatment at a lower temperature (170 °C) combined with ultrafine grinding achieved a high glucose yield (80.36%) at a low enzyme loading (5 filter paper unit (FPU)/g substrate) which is favorable. The relative significance of structural parameters in enzymatic hydrolyzability was SSA > PV > average pore size > CrI/cellulose > particle size. PV and SSA exhibited logarithmic correlations with the final enzymatic hydrolysis yield. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
3. Efficient Enzymatic Hydrolysis of Bamboo by Pretreatment with Steam Explosion and Alkaline Peroxide.
- Author
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Yang Xing, Hailong Yu, Liwei Zhu, and Jianxin Jiang
- Subjects
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HYDROLYSIS , *BAMBOO , *STEAM , *ALKALINE solutions , *HEMICELLULOSE , *SOLUBILIZATION , *X-ray photoelectron spectroscopy , *POLYMERIZATION - Abstract
A combination of steam explosion (SE) and alkaline peroxide (AP) used to pretreat bamboo was investigated. Steam explosion at 224 °C for 4 min was applied to bamboo, and the pretreated bamboo was delignified by alkaline peroxide. Enzymatic hydrolysis was compared in the pretreated samples. Steam pretreatment led to remarkable hemicellulose solubilization (63.2%). Lignin solubilization (93.1%) was achieved by alkaline peroxide treatment of steam-pretreated bamboo at 80 °C for 1 h in 0.88% (v/v) H2O2, whereas only 33.4% of lignin was solubilized when using raw bamboo. Pretreatment methods resulted in a low degree of polymerization and increased hydrolysis of cellulose. A maximum glucose yield of 90.5% was achieved with a combined steam explosion and alkaline peroxide pretreatment. The surface structure of treated bamboo and the adsorption of enzyme on the substrate were characterized by X-ray photoelectron spectroscopy. Delignification decreased enzyme adsorption and increased enzymatic conversion. SEM analyses indicated that SE-AP pretreatment disrupted lignin networks and exposed crystalline cellulose in bamboo more effectively than SE or AP pretreatment alone. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
4. Combinations of mild physical or chemical pretreatment with biological pretreatment for enzymatic hydrolysis of rice hull
- Author
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Yu, Jun, Zhang, Jibin, He, Jin, Liu, Ziduo, and Yu, Ziniu
- Subjects
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PLEUROTUS ostreatus , *HULLING of rice , *PLEUROTUS , *RICE hulls as fuel , *ALTERNATIVE fuels , *RICE hull ash , *ORYZA , *HYDROLYSIS - Abstract
Abstract: Two novel two-step pretreatments for enzymatic hydrolysis of rice hull (RH) were proposed to lower the severity requirement of fungal pretreatment time. They consisted of a mild physical or chemical step (ultrasonic and H2O2) and a subsequent biological treatment (Pleurotus ostreatus). The combined pretreatments led to significant increases of the lignin degradation than those of one step pretreatments. After enzymatic hydrolysis of the pretreated RH, the net yields of total soluble sugar (TS) and glucose (G) increased greatly. The combined pretreatment of H2O2 (2%, 48h) and P. ostreatus (18d) was more effective than sole pretreatment of P. ostreatus for 60d. It could remarkably shorten the residence time and reduce the losses of carbohydrates. Ligninase analyses and SEM observations indicated that the enhancing of the efficiency could possibly attribute to the structure disruption of the RH during the first pretreatment step. So, the combined pretreatment could be recommended to different lignocellulosic materials for enzyme based conversions. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
5. Enhanced Enzymatic Hydrolysis and Structural Features of Corn Stover by NaOH and Ozone Combined Pretreatment
- Author
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Shisheng Tong, Chunyan Zhang, Ping Liu, Zhongyi Cui, and Wenhui Wang
- Subjects
alkali ,Pharmaceutical Science ,02 engineering and technology ,combined pretreatment ,01 natural sciences ,Zea mays ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,Hydrolysis ,chemistry.chemical_compound ,corn stover ,fluids and secretions ,lcsh:Organic chemistry ,Cellulase ,Enzymatic hydrolysis ,Drug Discovery ,Lignin ,surface morphology ,Sodium Hydroxide ,Hemicellulose ,Biomass ,Physical and Theoretical Chemistry ,Fourier transform infrared spectroscopy ,Cellulose ,Stover ,Plant Stems ,010405 organic chemistry ,Chemistry ,beta-Glucosidase ,Organic Chemistry ,food and beverages ,enzymatic hydrolysis ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,stomatognathic diseases ,ozone ,Kinetics ,Corn stover ,Chemistry (miscellaneous) ,Molecular Medicine ,structural characteristics ,0210 nano-technology ,Nuclear chemistry - Abstract
A two-step pretreatment using NaOH and ozone was performed to improve the enzymatic hydrolysis, compositions and structural characteristics of corn stover. Comparison between the unpretreated and pretreated corn stover was also made to illustrate the mechanism of the combined pretreatment. A pretreatment with 2% (w/w) NaOH at 80 °, C for 2 h followed by ozone treatment for 25 min with an initial pH 9 was found to be the optimal procedure and the maximum efficiency (91.73%) of cellulose enzymatic hydrolysis was achieved. Furthermore, microscopic observation of changes in the surface structure of the samples showed that holes were formed and lignin and hemicellulose were partially dissolved and removed. X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13C-NMR) were also used to characterize the chemical structural changes after the combined pretreatment. The results were as follows: part of the cellulose I structure was destroyed and then reformed into cellulose III, the cellulose crystal indices were also changed, a wider space between the crystal layer was observed, disruption of hydrogen bonds in cellulose and disruption of ester bonds in hemicellulose, cleavage of bonds linkage in lignin-carbohydrate complexes, removal of methoxy in lignin and hemicellulose. As a result, all these changes effectively reduced recalcitrance of corn stover and promoted subsequent enzymatic hydrolysis of cellulose.
- Published
- 2018
6. Comparison of Enzymatic Hydrolysis of Bamboo Using Steam Explosion and Acid Sulfite, Alkali, and Alkaline Sulfite Pretreatments
- Author
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Pengxiang Zhao, Shubaichuan Qin, Jianxin Jiang, Dafeng Sun, Wang Yongmiao, Yang Xing, and Lingxi Bu
- Subjects
Bamboo ,Environmental Engineering ,lcsh:Biotechnology ,Inorganic chemistry ,Combined pretreatment ,Sulfonation ,Bioengineering ,Alkalization ,Hydrolysis ,chemistry.chemical_compound ,Glucose ,chemistry ,Sulfite ,lcsh:TP248.13-248.65 ,Enzymatic hydrolysis ,Yield (chemistry) ,Lignin ,Steam explosion ,Cellulose ,Waste Management and Disposal ,Nuclear chemistry - Abstract
A combination of steam explosion (SE) and chemical pretreatments, such as acid sulfite (AS), alkali (AL), and alkaline sulfite (ALS), were evaluated using bamboo. Low pressure steam explosion at 1.25 MPa for 4 min was first applied to the bamboo. Then, the pretreated bamboo was delignified using three chemical pretreatments. Enzymatic hydrolysis was also compared among the pretreated bamboo samples. It was found that SE-ALS could be a potential method for bamboo pretreatment, which led to the reduction of lignin from 25.15% to 1.74% at 165 °C for 2 h in 5% (w/v) Na2SO3 and 0.7% (w/v) NaOH; however, little cellulose was solubilized during ALS pretreatment. A maximum glucose yield of 99.35% was achieved during the enzymatic hydrolysis process when combined with the SE-ALS pretreatment. The SE-ALS method resulted in a lower degree of lignin condensation and increased delignification compared to the SE-AS method. In addition, the SE-ALS pretreatment protected carbohydrates from degradation better than the SE-AL methods.
- Published
- 2015
7. Enhanced Enzymatic Hydrolysis and Structural Features of Corn Stover by NaOH and Ozone Combined Pretreatment.
- Author
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Wang, Wenhui, Zhang, Chunyan, Tong, Shisheng, Cui, Zhongyi, and Liu, Ping
- Subjects
- *
HYDROLYSIS , *OZONE , *CORN stover , *CELLULOSE , *LIGNINS - Abstract
A two-step pretreatment using NaOH and ozone was performed to improve the enzymatic hydrolysis, compositions and structural characteristics of corn stover. Comparison between the unpretreated and pretreated corn stover was also made to illustrate the mechanism of the combined pretreatment. A pretreatment with 2% (
w /w ) NaOH at 80 °C for 2 h followed by ozone treatment for 25 min with an initial pH 9 was found to be the optimal procedure and the maximum efficiency (91.73%) of cellulose enzymatic hydrolysis was achieved. Furthermore, microscopic observation of changes in the surface structure of the samples showed that holes were formed and lignin and hemicellulose were partially dissolved and removed. X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13C-NMR) were also used to characterize the chemical structural changes after the combined pretreatment. The results were as follows: part of the cellulose I structure was destroyed and then reformed into cellulose III, the cellulose crystal indices were also changed; a wider space between the crystal layer was observed; disruption of hydrogen bonds in cellulose and disruption of ester bonds in hemicellulose; cleavage of bonds linkage in lignin-carbohydrate complexes; removal of methoxy in lignin and hemicellulose. As a result, all these changes effectively reduced recalcitrance of corn stover and promoted subsequent enzymatic hydrolysis of cellulose. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
8. Ensiling and hydrothermal pretreatment of grass: consequences for enzymatic biomass conversion and total monosaccharide yields
- Author
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Zsófia Kádár, Katja Salomon Johansen, Thomas Didion, Morten Ambye-Jensen, and Anne S. Meyer
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Bioconversion ,congenital, hereditary, and neonatal diseases and abnormalities ,grass ,Silage ,lignin ,Combined pretreatment ,temperature effect ,Hydrothermal treatment ,Management, Monitoring, Policy and Law ,Applied Microbiology and Biotechnology ,chemistry.chemical_compound ,Hydrolysis ,Enzymatic hydrolysis ,mental disorders ,monosaccharide ,otorhinolaryngologic diseases ,Monosaccharide ,Lignin ,Dry matter ,Ensiling ,Food science ,Biomass ,SDG 7 - Affordable and Clean Energy ,Cellulose ,glucose ,Sugar ,chemistry.chemical_classification ,Renewable Energy, Sustainability and the Environment ,Hydrothermal treatments ,Research ,Grass ,food and beverages ,enzyme ,General Energy ,Energy (all) ,chemistry ,Agronomy ,hydrolysis ,Festulolium ,dry matter ,Combined pre treatments ,solubilization ,Biotechnology - Abstract
Ensiling may act as a pretreatment of fresh grass biomass and increase the enzymatic conversion of structural carbohydrates to fermentable sugars. However, ensiling does not provide sufficient severity to be a standalone pretreatment method. Here, ensiling of grass is combined with hydrothermal treatment (HTT) with the aim of improving the enzymatic biomass convertibility and decrease the required temperature of the HTT. Results: Grass silage (Festulolium Hykor) was hydrothermally treated at temperatures of 170, 180, and 190°C for 10 minutes. Relative to HTT treated dry grass, ensiling increased the solubilization of dry matter (DM) during HTT and gave increased glucan content, but lower lignin in the insoluble fiber fraction. Ensiling improved glucose yields in the enzymatic hydrolysis of the washed solid fiber fraction at the lower HTT temperatures. At 170°C glucose yield improved from 17 to 24 (w/w)% (45 to 57% cellulose convertibility), and at 180°C glucose yield improved from 22 to 29 (w/w)% (54 to 69% cellulose convertibility). Direct HTT of grass at 190°C gave the same high glucose yield as for grass silage (35 (w/w)% (77% cellulose convertibility)) and improved xylan yields (27% xylan convertibility). The effect of ensiling of grass prior to HTT improved the enzymatic conversion of cellulose for HTT at 170 and 180°C, but the increased glucose release did not make up for the loss of water soluble carbohydrates (WSC) during ensiling. Overall, sugar yields (C6 + C5) were similar for HTT of grass and grass silage at both 170 and 180°C, but at 190°C the overall sugar yield was better for HTT of dry grass. Conclusions: This study unequivocally establishes that ensiling of grass as a biomass pretreatment method comes with a loss of WSC. The loss of WSC by ensiling is not necessarily compensated for by providing a lower temperature requirement for HTT for high enzymatic monosaccharide release. However, ensiling can be an advantageous storage method prior to grass processing. © 2014 Ambye-Jensen et al.; licensee BioMed Central Ltd.
- Published
- 2014
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