1
|
Cellulose-degrading enzymes: key players in biorefinery development. Biologia (Bratisl) 2022. [DOI: 10.1007/s11756-022-01274-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
2
|
Li M, Jiang B, Wu W, Wu S, Yang Y, Song J, Ahmad M, Jin Y. Current understanding and optimization strategies for efficient lignin-enzyme interaction: A review. Int J Biol Macromol 2022; 195:274-286. [PMID: 34883164 DOI: 10.1016/j.ijbiomac.2021.11.188] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/24/2021] [Accepted: 11/27/2021] [Indexed: 11/29/2022]
Abstract
From energy perspective, with abundant polysaccharides (45-85%), the renewable lignocellulosic is recognized as the 2nd generation feedstock for bioethanol and bio-based products production. Enzymatic hydrolysis is a critical pathway to yield fermentable monosaccharides from pretreated substrates of lignocellulose. Nevertheless, the lignin presence in lignocellulosic substrates leads to the low substrate enzymatic digestibility ascribed to the nonproductive adsorption. It has been reported that the water-soluble lignin (low molecular weight, sulfonated/sulfomethylated and graft polymer) enhance the rate of enzymatic digestibility, however, the catalytic mechanism of lignin-enzyme interaction remains elusive. In this review, optimization strategies for enzymatic hydrolysis based on the lignin structural modification, enzyme engineering, and different additives are critically reviewed. Lignin-enzyme interaction mechanism is also discussed (lignin and various cellulases). In addition, the mathematical models and simulation of lignin, cellulose and enzyme aims for promoting an integrated biomass-conversion process for sustainable production of value-added biofuels.
Collapse
Affiliation(s)
- Mohan Li
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, China
| | - Bo Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, China; Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Wenjuan Wu
- Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Shufang Wu
- Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Yiqin Yang
- Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Junlong Song
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, China; Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Mehraj Ahmad
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, China; Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Yongcan Jin
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, China; Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China.
| |
Collapse
|
3
|
Abstract
In cranberry production systems, stands are covered by 1–5 cm of sand every 2–5 years to stimulate plant growth, resulting in alternate layers of sand and litter in soil upper layers. However, almost intact twigs and leaves remain in subsurface layers, indicating a slow decomposition rate. The Tea Bag Index (TBI) provides an internationally standardized methodology to compare litter decomposition rates (k) and stabilization (S) among terrestrial ecosystems. However, TBI parameters may be altered by time-dependent changes in the contact between litter and their immediate environment. The aims of this study were to determine the TBI of cranberry agroecosystems and compare it to the TBI of other terrestrial ecosystems. Litters were standardized green tea, standardized rooibos tea, and cranberry residues collected on the plantation floor. Litter decomposition was monitored during two consecutive years. Added N did not affect TBI parameters (k and S) due to possible N leaching and strong acidic soil condition. Decomposition rates (k) averaged (mean ± SD) 9.7 × 10−3 day−1 ± 1.6 × 10−3 for green tea, 3.3 × 10−3 day−1 ± 0.8 × 10−5 for rooibos tea, and 0.4 × 10−3 day−1 ± 0.86 × 10−3 for cranberry residues due to large differences in biochemical composition and tissue structure. The TBI decomposition rate (k) was 0.006 day−1 ± 0.002 in the low range among terrestrial ecosystems, and the stabilization factor (S) was 0.28 ± 0.08, indicating high potential for carbon accumulation in cranberry agroecosystems. Decomposition rates of tea litters were reduced by fractal coefficients of 0.6 for green tea and 0.4 for rooibos tea, indicating protection mechanisms building up with time in the tea bags. While the computation of the TBI stabilization factor may be biased because the green tea was not fully decomposed, fractal kinetics could be used as additional index to compare agroecosystems.
Collapse
|
4
|
Chan KL, Ko CH, Chang KL, Leu SY. Construction of a structural enzyme adsorption/kinetics model to elucidate additives associated lignin-cellulase interactions in complex bioconversion system. Biotechnol Bioeng 2021; 118:4065-4075. [PMID: 34245458 DOI: 10.1002/bit.27883] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/21/2021] [Accepted: 07/04/2021] [Indexed: 11/07/2022]
Abstract
Enzymatic hydrolysis is a rate-limiting process in lignocellulose biorefinery. The reaction involves complex enzyme-substrate and enzyme-lignin interactions in both liquid and solid phases, and has not been well characterized numerically. In this study, a kinetic model was developed to incorporate dynamic enzyme adsorption and product inhibition parameters into hydrolysis simulation. The enzyme adsorption coefficients obtained from Langmuir isotherm were fed dynamically into first-order kinetics for simulating the equilibrium enzyme adsorption in hydrolysis. A fractal and product inhibition kinetics was introduced and successfully applied to improve the simulation accuracy on adsorbed enzyme and glucose concentrations at different enzyme loadings, lignin contents, and in the presence of bovine serum albumin (BSA) and lysozyme. The model provided numerical proof quantifying the beneficial effects of both additives, which improved the hydrolysis rate by reducing the nonproductive adsorption of enzyme on lignin. The hydrolysis rate coefficient and fractal exponent both increased with increasing enzyme loadings, and lignin inhibition exhibited with increasing fractal exponent. Compared with BSA, the addition of lysozyme exhibited higher hydrolysis rates, which was reflected in the larger hydrolysis rate coefficients and smaller fractal exponents in the simulation. The model provides new insights to support process development, control, and optimization.
Collapse
Affiliation(s)
- Ka-Lai Chan
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Chun-Han Ko
- Research Institute for Sustainable Urban Development (RISUD), The Hong Kong Polytechnic University, Hung Hom, Hong Kong.,School of Forest and Resources Conservation, National Taiwan University, Taipei, Taiwan
| | - Ken-Lin Chang
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Hong Kong.,Research Institute for Sustainable Urban Development (RISUD), The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| |
Collapse
|
5
|
Wojtusik M, Vergara P, Villar JC, Ladero M, García-Ochoa F. Enzymatic hydrolysis of several pretreated lignocellulosic biomasses: Fractal kinetic modelling. BIORESOURCE TECHNOLOGY 2020; 318:124050. [PMID: 32889118 DOI: 10.1016/j.biortech.2020.124050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Enzymatic hydrolysis of three pre-treated lignocellulosic biomasses -LCB- (wheat straw-WS-, corn stover-CSV- and cardoon stems -CS-) is studied. These biomasses were pre-treated by two methods: diluted sulfuric acid and acid ethanol-water extraction at six severity levels (H values). Pretreated solid fractions were hydrolyzed with commercial enzyme cocktails at standard conditions. A first-order kinetic fractal model was fitted to the experimental results. This model accurately describes the hydrolysis of all biomasses at all pre-treatment conditions studied. The results show that the formal first-order kinetic constant k depends on the biomass nature. The hydrolysis rate increases as the pre-treatment severity does, while the fractal exponent value h decreases. With these pre-treatments, and in terms of k and h, WS is highly reactive and, at medium H with EW pretreatment, highly accessible; CSV has a low reactivity and high accessibility and CS has the lowest reactivity and an increasing accessibility as severity rises.
Collapse
Affiliation(s)
- Mateusz Wojtusik
- Chemical Engineering & Materials Department. Faculty of Chemistry, Universidad Complutense, 28040 Madrid, Spain
| | - Priscilla Vergara
- Chemical Engineering & Materials Department. Faculty of Chemistry, Universidad Complutense, 28040 Madrid, Spain; Laboratory of Cellulose & Paper. Forest Research Center - INIA, Ctra. de La Coruña km 7.5, 28040 Madrid, Spain
| | - Juan C Villar
- Laboratory of Cellulose & Paper. Forest Research Center - INIA, Ctra. de La Coruña km 7.5, 28040 Madrid, Spain
| | - Miguel Ladero
- Chemical Engineering & Materials Department. Faculty of Chemistry, Universidad Complutense, 28040 Madrid, Spain.
| | - Félix García-Ochoa
- Chemical Engineering & Materials Department. Faculty of Chemistry, Universidad Complutense, 28040 Madrid, Spain
| |
Collapse
|
6
|
Abdou Alio M, Tugui OC, Rusu L, Pons A, Vial C. Hydrolysis and fermentation steps of a pretreated sawmill mixed feedstock for bioethanol production in a wood biorefinery. BIORESOURCE TECHNOLOGY 2020; 310:123412. [PMID: 32361645 DOI: 10.1016/j.biortech.2020.123412] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 06/11/2023]
Abstract
The aim of this work was to demonstrate the feasibility of second-generation bioethanol production using for the first time a sawmill mixed feedstock comprising four softwood species, representative of biomass resource in Auvergne-Rhône-Alpes region (France). The feedstock was subjected to a microwave-assisted water/ethanol Organosolv pretreatment. The investigation focused on enzymatic hydrolysis of this pretreated sawmill feedstock (PSF) using Cellic® Ctec2 as the enzyme, followed by fermentation of the resulting sugar solution using Saccharomyces cerevisiae strain. The cellulose-rich PSF with 71% w/w cellulose content presented high saccharification yields (up to 80%), which made it perfect for subsequent fermentation; this yield was predicted vs. time up to 5.2% w/v PSF loading using a mathematical model fitted only on data at 1.5%. Finally, high PSF loading (7.5%) and scaleup were shown to impair the saccharification yield, but alcoholic fermentation could still be carried out up to 80% of the theoretical glucose-to-ethanol conversion yield.
Collapse
Affiliation(s)
- Maarouf Abdou Alio
- Université Clermont Auvergne, CNRS, Sigma Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France
| | - Oana-Cristina Tugui
- University "Vasile Alecsandri" of Bacău, Faculty of Engineering, Chemical and Food Engineering Department, Bacău, Romania
| | - Lacramioara Rusu
- University "Vasile Alecsandri" of Bacău, Faculty of Engineering, Chemical and Food Engineering Department, Bacău, Romania
| | - Agnès Pons
- Université Clermont Auvergne, CNRS, Sigma Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France
| | - Christophe Vial
- Université Clermont Auvergne, CNRS, Sigma Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France.
| |
Collapse
|
7
|
Escobar ELN, da Silva TA, Pirich CL, Corazza ML, Pereira Ramos L. Supercritical Fluids: A Promising Technique for Biomass Pretreatment and Fractionation. Front Bioeng Biotechnol 2020; 8:252. [PMID: 32391337 PMCID: PMC7191036 DOI: 10.3389/fbioe.2020.00252] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/11/2020] [Indexed: 11/17/2022] Open
Abstract
Lignocellulosic biomasses are primarily composed of cellulose, hemicelluloses and lignin and these biopolymers are bonded together in a heterogeneous matrix that is highly recalcitrant to chemical or biological conversion processes. Thus, an efficient pretreatment technique must be selected and applied to this type of biomass in order to facilitate its utilization in biorefineries. Classical pretreatment methods tend to operate under severe conditions, leading to sugar losses by dehydration and to the release of inhibitory compounds such as furfural (2-furaldehyde), 5-hydroxy-2-methylfurfural (5-HMF), and organic acids. By contrast, supercritical fluids can pretreat lignocellulosic materials under relatively mild pretreatment conditions, resulting in high sugar yields, low production of fermentation inhibitors and high susceptibilities to enzymatic hydrolysis while reducing the consumption of chemicals, including solvents, reagents, and catalysts. This work presents a review of biomass pretreatment technologies, aiming to deliver a state-of-art compilation of methods and results with emphasis on supercritical processes.
Collapse
Affiliation(s)
- Estephanie Laura Nottar Escobar
- Applied Kinetics and Thermodynamics Laboratory, Department of Chemical Engineering, Federal University of Paraná, Curitiba, Brazil
| | - Thiago Alessandre da Silva
- Department of Chemistry, Research Center in Applied Chemistry, Federal University of Paraná, Curitiba, Brazil
| | - Cleverton Luiz Pirich
- Department of Chemistry, Research Center in Applied Chemistry, Federal University of Paraná, Curitiba, Brazil
| | - Marcos Lúcio Corazza
- Applied Kinetics and Thermodynamics Laboratory, Department of Chemical Engineering, Federal University of Paraná, Curitiba, Brazil
| | - Luiz Pereira Ramos
- Department of Chemistry, Research Center in Applied Chemistry, Federal University of Paraná, Curitiba, Brazil
| |
Collapse
|
8
|
Patri AS, Mostofian B, Pu Y, Ciaffone N, Soliman M, Smith MD, Kumar R, Cheng X, Wyman CE, Tetard L, Ragauskas AJ, Smith JC, Petridis L, Cai CM. A Multifunctional Cosolvent Pair Reveals Molecular Principles of Biomass Deconstruction. J Am Chem Soc 2019; 141:12545-12557. [PMID: 31304747 DOI: 10.1021/jacs.8b10242] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complex structure of plant cell walls resists chemical or biological degradation, challenging the breakdown of lignocellulosic biomass into renewable chemical precursors that could form the basis of future production of green chemicals and transportation fuels. Here, experimental and computational results reveal that the effect of the tetrahydrofuran (THF)-water cosolvents on the structure of lignin and on its interactions with cellulose in the cell wall drives multiple synergistic mechanisms leading to the efficient breakdown and fractionation of biomass into valuable chemical precursors. Molecular simulations show that THF-water is an excellent "theta" solvent, such that lignin dissociates from itself and from cellulose and expands to form a random coil. The expansion of the lignin molecules exposes interunit linkages, rendering them more susceptible to depolymerization by acid-catalyzed cleavage of aryl-ether bonds. Nanoscale infrared sensors confirm cosolvent-mediated molecular rearrangement of lignin in the cell wall of micrometer-thick hardwood slices and track the disappearance of lignin. At bulk scale, adding dilute acid to the cosolvent mixture liberates the majority of the hemicellulose and lignin from biomass, allowing unfettered access of cellulolytic enzymes to the remaining cellulose-rich material, allowing them to sustain high rates of hydrolysis to glucose without enzyme deactivation. Through this multiscale analysis, synergistic mechanisms for biomass deconstruction are identified, portending a paradigm shift toward first-principles design and evaluation of other cosolvent methods to realize low cost fuels and bioproducts.
Collapse
Affiliation(s)
- Abhishek S Patri
- Department of Chemical and Environmental Engineering, Bourns College of Engineering , University of California, Riverside , 900 University Avenue , Riverside , California 92521 , United States.,Center for Environmental Research and Technology, Bourns College of Engineering , University of California, Riverside , 1084 Columbia Avenue , Riverside , California 92507 , United States
| | | | | | - Nicholas Ciaffone
- NanoScience Technology Center and ¶Department of Physics , University of Central Florida , Orlando , Florida 32826 , United States
| | - Mikhael Soliman
- NanoScience Technology Center and ¶Department of Physics , University of Central Florida , Orlando , Florida 32826 , United States
| | | | - Rajeev Kumar
- Center for Environmental Research and Technology, Bourns College of Engineering , University of California, Riverside , 1084 Columbia Avenue , Riverside , California 92507 , United States
| | - Xiaolin Cheng
- College of Pharmacy , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Charles E Wyman
- Department of Chemical and Environmental Engineering, Bourns College of Engineering , University of California, Riverside , 900 University Avenue , Riverside , California 92521 , United States.,Center for Environmental Research and Technology, Bourns College of Engineering , University of California, Riverside , 1084 Columbia Avenue , Riverside , California 92507 , United States
| | - Laurene Tetard
- NanoScience Technology Center and ¶Department of Physics , University of Central Florida , Orlando , Florida 32826 , United States
| | | | | | | | - Charles M Cai
- Department of Chemical and Environmental Engineering, Bourns College of Engineering , University of California, Riverside , 900 University Avenue , Riverside , California 92521 , United States.,Center for Environmental Research and Technology, Bourns College of Engineering , University of California, Riverside , 1084 Columbia Avenue , Riverside , California 92507 , United States
| |
Collapse
|
9
|
Yu CA, Yang CY. Bio-ionic liquid pretreatment and ultrasound-promoted enzymatic hydrolysis of black soybean okara. J Biosci Bioeng 2019; 127:767-773. [PMID: 30638804 DOI: 10.1016/j.jbiosc.2018.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/09/2018] [Accepted: 12/16/2018] [Indexed: 11/19/2022]
Abstract
The effective processing method to produce fermentable sugars and modify the microstructure of black soybean okara using bio-ionic liquid (bio-IL) pretreatment and ultrasound-promoted enzymatic hydrolysis was investigated. The morphology and structural characteristics of okara before and after bio-IL pretreatment and enzymatic hydrolysis under different ultrasonic frequencies were analyzed by field emission scanning electron microscope (FE-SEM), X-ray energy dispersive spectrometer (EDS), and Fourier transform infrared spectroscopy (FTIR). Without pretreatment, the production of total reducing sugar (TRS) under ultrasound (40 kHz/300 W) was 3.4 times of that without ultrasound. Using the bio-IL choline acetate ([Ch][OAc]) in water for the pretreatment of black soybean okara, the TRS production of enzymatic hydrolysis was further increased to 5.2 times of that without ultrasound in 4 h of reaction. The analysis by FTIR and EDS showed that the highly structured matrix of okara was unfolded and broken by the action of combining ultrasound and choline acetate pretreatment, due to which the surface structures with large pores were presented to facilitate the reduction of unfavorable hindrance for enzymatic hydrolysis. The simplified kinetic model was proposed to describe the transport and reaction phenomena of enzymes in a solid-liquid system by using two kinetic parameters to show the impeded behavior of enzyme within the matrix of okara. The combination of bio-IL pretreatment and ultrasound-promoted enzymatic hydrolysis was able to make the efficient structural changes of black soybean okara to enhance the digestion of enzymes, and the okara could be valorized for use in foods.
Collapse
Affiliation(s)
- Cheng-An Yu
- Department of Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City 24205, Taiwan, ROC
| | - Chun-Yao Yang
- Department of Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City 24205, Taiwan, ROC.
| |
Collapse
|
10
|
Zhang Y, Di X, Xu J, Shao J, Qi W, Yuan Z. Effect of LHW, HCl, and NaOH pretreatment on enzymatic hydrolysis of sugarcane bagasse: sugar recovery and fractal-like kinetics. CHEM ENG COMMUN 2018. [DOI: 10.1080/00986445.2018.1525365] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yu Zhang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
- CAS Key Laboratory of Renewable Energy, Guangzhou, China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou, China
| | - Xiaohui Di
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
- CAS Key Laboratory of Renewable Energy, Guangzhou, China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jingliang Xu
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
- CAS Key Laboratory of Renewable Energy, Guangzhou, China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou, China
| | - Junchao Shao
- Guangzhou Foreign Language School, Guangzhou, China
| | - Wei Qi
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
- CAS Key Laboratory of Renewable Energy, Guangzhou, China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou, China
| | - Zhenhong Yuan
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
- CAS Key Laboratory of Renewable Energy, Guangzhou, China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou, China
| |
Collapse
|
11
|
Wang W, Wang Q, Tan X, Qi W, Yu Q, Zhuang X, Yuan Z. The Ways of Factors Influencing High-Solid Enzymatic Hydrolysis of Sugarcane Bagasse Treated by Liquid Hot Water. ChemistrySelect 2017. [DOI: 10.1002/slct.201701353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wen Wang
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
| | - Qiong Wang
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
| | - Xuesong Tan
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
| | - Wei Qi
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
| | - Qiang Yu
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
| | - Xinshu Zhuang
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
| | - Zhenhong Yuan
- Guangzhou Institute of Energy Conversion; Chinese Academy of Sciences; CAS Key Laboratory of Renewable Energy; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development; No. 2 Nengyuan Road, Wushan, Tianhe District Guangzhou 510640 China
- Collaborative Innovation Center of Biomass Energy; No. 63 Agricultural Road, Jinshui District Zhengzhou 450002 China
| |
Collapse
|
12
|
Antonov E, Schlembach I, Regestein L, Rosenbaum MA, Büchs J. Process relevant screening of cellulolytic organisms for consolidated bioprocessing. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:106. [PMID: 28450887 PMCID: PMC5402656 DOI: 10.1186/s13068-017-0790-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/12/2017] [Indexed: 05/28/2023]
Abstract
BACKGROUND Although the biocatalytic conversion of cellulosic biomass could replace fossil oil for the production of various compounds, it is often not economically viable due to the high costs of cellulolytic enzymes. One possibility to reduce costs is consolidated bioprocessing (CBP), integrating cellulase production, hydrolysis of cellulose, and the fermentation of the released sugars to the desired product into one process step. To establish such a process, the most suitable cellulase-producing organism has to be identified. Thereby, it is crucial to evaluate the candidates under target process conditions. In this work, the chosen model process was the conversion of cellulose to the platform chemical itaconic acid by a mixed culture of a cellulolytic fungus with Aspergillus terreus as itaconic acid producer. Various cellulase producers were analyzed by the introduced freeze assay that measures the initial carbon release rate, quantifying initial cellulase activity under target process conditions. Promising candidates were then characterized online by monitoring their respiration activity metabolizing cellulose to assess the growth and enzyme production dynamics. RESULTS The screening of five different cellulase producers with the freeze assay identified Trichoderma reesei and Penicillium verruculosum as most promising. The measurement of the respiration activity revealed a retarded induction of cellulase production for P. verruculosum but a similar cellulase production rate afterwards, compared to T. reesei. The freeze assay measurement depicted that P. verruculosum reaches the highest initial carbon release rate among all investigated cellulase producers. After a modification of the cultivation procedure, these results were confirmed by the respiration activity measurement. To compare both methods, a correlation between the measured respiration activity and the initial carbon release rate of the freeze assay was introduced. The analysis revealed that the different initial enzyme/cellulose ratios as well as a discrepancy in cellulose digestibility are the main differences between the two approaches. CONCLUSIONS With two complementary methods to quantify cellulase activity and the dynamics of cellulase production for CBP applications, T. reesei and P. verruculosum were identified as compatible candidates for the chosen model process. The presented methods can easily be adapted to screen for suitable cellulose degrading organisms for various other applications.
Collapse
Affiliation(s)
- Elena Antonov
- AVT‑Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, 52074 Aachen, Germany
| | - Ivan Schlembach
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Lars Regestein
- AVT‑Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, 52074 Aachen, Germany
| | - Miriam A. Rosenbaum
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Jochen Büchs
- AVT‑Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, 52074 Aachen, Germany
| |
Collapse
|
13
|
Tervasmäki P, Sotaniemi V, Kangas J, Taskila S, Ojamo H, Tanskanen J. A discretized model for enzymatic hydrolysis of cellulose in a fed-batch process. BIORESOURCE TECHNOLOGY 2017; 227:112-124. [PMID: 28013127 DOI: 10.1016/j.biortech.2016.12.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 12/12/2016] [Accepted: 12/14/2016] [Indexed: 05/24/2023]
Abstract
In the enzymatic hydrolysis of cellulose, several phenomena have been proposed to cause a decrease in the reaction rate with increasing conversion. The importance of each phenomenon is difficult to distinguish from batch hydrolysis data. Thus, kinetic models for the enzymatic hydrolysis of cellulose often suffer from poor parameter identifiability. This work presents a model that is applicable to fed-batch hydrolysis by discretizing the substrate based on the feeding time. Different scenarios are tested to explain the observed decrease in reaction rate with increasing conversion, and comprehensive assessment of the parameter sensitivities is carried out. The proposed model performed well in the broad range of experimental conditions used in this study and when compared to literature data. Furthermore, the use of data from fed-batch experiments and discretization of the model substrate to populations was found to be very informative when assessing the importance of the rate-decreasing phenomena in the model.
Collapse
Affiliation(s)
- Petri Tervasmäki
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland.
| | - Ville Sotaniemi
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| | - Jani Kangas
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| | - Sanna Taskila
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| | - Heikki Ojamo
- Department of Biotechnology and Chemical Technology, School of Chemical Technology, Aalto University, P.O. Box 16100, 00076, Aalto, Finland
| | - Juha Tanskanen
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| |
Collapse
|
14
|
Wojtusik M, Zurita M, Villar JC, Ladero M, Garcia-Ochoa F. Enzymatic saccharification of acid pretreated corn stover: Empirical and fractal kinetic modelling. BIORESOURCE TECHNOLOGY 2016; 220:110-116. [PMID: 27566519 DOI: 10.1016/j.biortech.2016.08.069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 06/06/2023]
Abstract
Enzymatic hydrolysis of corn stover was studied at agitation speeds from 50 to 500rpm in a stirred tank bioreactor, at high solid concentrations (20% w/w dry solid/suspension), 50°C and 15.5mgprotein·gglucane(-1). Two empirical kinetic models have been fitted to empirical data, namely: a potential model and a fractal one. For the former case, the global order dramatically decreases from 13 to 2 as agitation speed increases, suggesting an increment in the access of enzymes to cellulose in terms of chemisorption followed by hydrolysis. For its part, the fractal kinetic model fits better to data, showing its kinetic constant a constant augmentation with increasing agitation speed up to a constant value at 250rpm and above, when mass transfer limitations are overcome. In contrast, the fractal exponent decreases with rising agitation speed till circa 0.19, suggesting higher accessibility of enzymes to the substrate.
Collapse
Affiliation(s)
- Mateusz Wojtusik
- Chemical Engineering Department, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
| | - Mauricio Zurita
- Abengoa Research, Campus de Palmas Altas, 41014 Sevilla, Spain
| | - Juan C Villar
- Laboratory of Cellulose and Paper, INIA, Forest Research Center, Ctra. de la Coruña km 7.5, 28040 Madrid, Spain
| | - Miguel Ladero
- Chemical Engineering Department, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
| | - Felix Garcia-Ochoa
- Chemical Engineering Department, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
| |
Collapse
|
15
|
Wang M, Han L, Liu S, Zhao X, Yang J, Loh SK, Sun X, Zhang C, Fang X. A Weibull statistics-based lignocellulose saccharification model and a built-in parameter accurately predict lignocellulose hydrolysis performance. Biotechnol J 2015; 10:1424-33. [DOI: 10.1002/biot.201400723] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/09/2015] [Accepted: 06/25/2015] [Indexed: 11/11/2022]
|
16
|
Nguyen TY, Cai CM, Kumar R, Wyman CE. Co-solvent pretreatment reduces costly enzyme requirements for high sugar and ethanol yields from lignocellulosic biomass. CHEMSUSCHEM 2015; 8:1716-25. [PMID: 25677100 DOI: 10.1002/cssc.201403045] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/07/2014] [Indexed: 05/11/2023]
Abstract
We introduce a new pretreatment called co-solvent-enhanced lignocellulosic fractionation (CELF) to reduce enzyme costs dramatically for high sugar yields from hemicellulose and cellulose, which is essential for the low-cost conversion of biomass to fuels. CELF employs THF miscible with aqueous dilute acid to obtain up to 95 % theoretical yield of glucose, xylose, and arabinose from corn stover even if coupled with enzymatic hydrolysis at only 2 mgenzyme gglucan (-1) . The unusually high saccharification with such low enzyme loadings can be attributed to a very high lignin removal, which is supported by compositional analysis, fractal kinetic modeling, and SEM imaging. Subsequently, nearly pure lignin product can be precipitated by the evaporation of volatile THF for recovery and recycling. Simultaneous saccharification and fermentation of CELF-pretreated solids with low enzyme loadings and Saccharomyces cerevisiae produced twice as much ethanol as that from dilute-acid-pretreated solids if both were optimized for corn stover.
Collapse
Affiliation(s)
- Thanh Yen Nguyen
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, 1084 Columbia Avenue, Riverside, California 92507 (USA), Fax: (+1) 951-781-5790
- Department of Bioengineering, Bourns College of Engineering, University of California, Riverside, 217 Materials Science & Engineering, 900 University Ave., Riverside, CA 92507 (USA)
| | - Charles M Cai
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, 1084 Columbia Avenue, Riverside, California 92507 (USA), Fax: (+1) 951-781-5790
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, 446 Winston Chung Hall, 900 University Ave., Riverside, CA 92507 (United States)
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (USA)
| | - Rajeev Kumar
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, 1084 Columbia Avenue, Riverside, California 92507 (USA), Fax: (+1) 951-781-5790
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (USA)
| | - Charles E Wyman
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, 1084 Columbia Avenue, Riverside, California 92507 (USA), Fax: (+1) 951-781-5790.
- Department of Bioengineering, Bourns College of Engineering, University of California, Riverside, 217 Materials Science & Engineering, 900 University Ave., Riverside, CA 92507 (USA).
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, 446 Winston Chung Hall, 900 University Ave., Riverside, CA 92507 (United States).
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (USA).
| |
Collapse
|
17
|
Silveira MHL, de Siqueira FG, Rau M, Silva LD, Moreira LRDS, Ferreira-Filho EX, Andreaus J. Hydrolysis of sugarcane bagasse with enzyme preparations fromAcrophialophora nainianagrown on different carbon sources. BIOCATAL BIOTRANSFOR 2014. [DOI: 10.3109/10242422.2013.872634] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
18
|
Aguiar RS, Silveira MHL, Pitarelo AP, Corazza ML, Ramos LP. Kinetics of enzyme-catalyzed hydrolysis of steam-exploded sugarcane bagasse. BIORESOURCE TECHNOLOGY 2013; 147:416-423. [PMID: 24007721 DOI: 10.1016/j.biortech.2013.08.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/08/2013] [Accepted: 08/09/2013] [Indexed: 05/16/2023]
Abstract
This work presents the experimental kinetic data and the fractal modeling of sugarcane bagasse steam treatment and enzymatic hydrolysis. Sugarcane bagasse (50 wt% moisture) was pretreated by autohydrolysis at 210 °C for 4 min. Acid catalysis involved the use of 9.5mg g(-1) of H2SO4 or H3PO4 in relation to the substrate dry mass at these same pretreatment conditions. Unwashed, water-washed and alkali-washed substrates were hydrolyzed at 2.0 wt% using 8 and 15 FPU g(-1) (108.22 and 199.54 mg/g) total solids of a Celluclast 1.5 L and Novozym 188 mixture (Novozymes). The fractal kinetic modeling was used to describe the effect of pretreatment and both washing processes on substrate accessibility. Water and/or alkali washing was not strictly necessary to achieve high hydrolysis efficiencies. Also, the fractal model coefficients revealed that H3PO4 was a better pretreatment catalyst under the experimental conditions used in this study, resulting in the most susceptible substrates for enzymatic hydrolysis.
Collapse
Affiliation(s)
- Rodrigo Souza Aguiar
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná (UFPR), Curitiba PR 81531-990, Brazil; Department of Chemical Engineering, Federal University of Paraná (UFPR), Curitiba, PR 82530-990, Brazil
| | - Marcos Henrique Luciano Silveira
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná (UFPR), Curitiba PR 81531-990, Brazil
| | - Ana Paula Pitarelo
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná (UFPR), Curitiba PR 81531-990, Brazil
| | - Marcos Lucio Corazza
- Department of Chemical Engineering, Federal University of Paraná (UFPR), Curitiba, PR 82530-990, Brazil
| | - Luiz Pereira Ramos
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná (UFPR), Curitiba PR 81531-990, Brazil.
| |
Collapse
|
19
|
Tian SQ, Ma S, Wang XW, Zhang ZN. Fractal kinetic analysis of the enzymatic saccharification of CO2 laser pretreated corn stover. Carbohydr Polym 2013; 98:618-23. [DOI: 10.1016/j.carbpol.2013.06.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 05/27/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
|
20
|
Newman RH, Vaidya AA, Sohel MI, Jack MW. Optimizing the enzyme loading and incubation time in enzymatic hydrolysis of lignocellulosic substrates. BIORESOURCE TECHNOLOGY 2013; 129:33-8. [PMID: 23232221 DOI: 10.1016/j.biortech.2012.11.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/05/2012] [Accepted: 11/05/2012] [Indexed: 05/14/2023]
Abstract
A mathematical model for costing enzymatic hydrolysis of lignocellulosics is presented. This model is based on three variable parameters describing substrate characteristics and three unit costs for substrate, enzymes and incubation. The model is used to minimize the cost of fermentable sugars, as intermediate products on the route to ethanol or other biorefinery products, by calculating optimized values of enzyme loading and incubation time. This approach allows comparisons between substrates, with processing conditions optimized independently for each substrate. Steam-exploded pine wood was hydrolyzed in order to test the theoretical relationship between sugar yield and processing conditions.
Collapse
Affiliation(s)
- Roger H Newman
- Scion, Private Bag 3020, Rotorua Mail Centre, Rotorua 3046, New Zealand.
| | | | | | | |
Collapse
|
21
|
Newman RH, Vaidya AA, Campion SH. A mathematical model for the inhibitory effects of lignin in enzymatic hydrolysis of lignocellulosics. BIORESOURCE TECHNOLOGY 2013; 130:757-762. [PMID: 23340076 DOI: 10.1016/j.biortech.2012.12.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 11/09/2012] [Accepted: 12/16/2012] [Indexed: 06/01/2023]
Abstract
A new model for enzymatic hydrolysis of lignocellulosic biomass distinguishes causal influences from enzyme deactivation and restrictions on the accessibility of cellulose. It focuses on calculating the amount of unreacted cellulose at cessation of enzyme activity, unlike existing models that were constructed for calculating the time dependence of conversion. There are three adjustable parameters: (1) 'occluded cellulose' is defined as cellulose that cannot be hydrolysed regardless of enzyme loading or incubation time, (2) a 'characteristic enzyme loading' is sufficient to hydrolyse half of the non-occluded cellulose, (3) a 'mechanism index' measures deviations from first-order kinetics. This model was used to predict that the optimal incubation temperature is lower for lignocellulosics than for pure cellulose. For steam-exploded pine wood after 96h incubation, occluded cellulose was 24% and 26% at 30°C and 50°C, and the characteristic enzyme loadings were 10 and 18FPU/g substrate, respectively.
Collapse
Affiliation(s)
- Roger H Newman
- Scion, Private Bag 3020, Rotorua Mail Centre, Rotorua 3046, New Zealand.
| | | | | |
Collapse
|
22
|
Chen K, Xu L, Bi Z, Fu Z. Kinetics analysis of the enzymatic hydrolysis of cellulose from straw stalk. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11631-013-0605-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
23
|
Evaluating kinetics of enzymatic saccharification of lignocellulose by fractal kinetic analysis. BIOTECHNOL BIOPROC E 2011. [DOI: 10.1007/s12257-011-0283-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
24
|
A Fractal-Like Kinetic Equation to Investigate Temperature Effect on Cellulose Hydrolysis by Free and Immobilized Cellulase. Appl Biochem Biotechnol 2011; 168:144-53. [DOI: 10.1007/s12010-011-9362-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 09/01/2011] [Indexed: 10/17/2022]
|
25
|
Wang Z, Xu JH, Feng H, Qi H. Fractal kinetic analysis of polymers/nonionic surfactants to eliminate lignin inhibition in enzymatic saccharification of cellulose. BIORESOURCE TECHNOLOGY 2011; 102:2890-2896. [PMID: 21093257 DOI: 10.1016/j.biortech.2010.10.132] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 10/25/2010] [Accepted: 10/26/2010] [Indexed: 05/30/2023]
Abstract
The profile of enzymatic saccharification of Avicel in the presence and absence of lignin has been described with a fractal kinetic model (Wang and Feng, 2010), in which the retarded hydrolysis rate of enzymatic saccharification of cellulose has been represented with a fractal exponent. The lignin inhibition in the enzymatic saccharification of cellulose is indexed by the increase of fractal exponent, which can not be fully counterbalanced by high cellulase loading due to the high fractal exponent at high cellulase loading. On the contrary, fractal kinetic analysis indicates that an addition of some nonionic surfactant/polymers decrease the fractal exponent to the original values of enzymatic saccharification of Avicel without lignin and the corresponding toxicity of nonionic surfactants/polymers on the consecutive ethanol fermentation strain Saccharomyces cerevisiae is also examined.
Collapse
Affiliation(s)
- Zhilong Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, PR China.
| | | | | | | |
Collapse
|