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Mohammadi M, Alian M, Dale B, Ubanwa B, Balan V. Multifaced application of AFEX-pretreated biomass in producing second-generation biofuels, ruminant animal feed, and value-added bioproducts. Biotechnol Adv 2024; 72:108341. [PMID: 38499256 DOI: 10.1016/j.biotechadv.2024.108341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/06/2024] [Accepted: 03/15/2024] [Indexed: 03/20/2024]
Abstract
Lignocellulosic biomass holds a crucial position in the prospective bio-based economy, serving as a sustainable and renewable source for a variety of bio-based products. These products play a vital role in displacing fossil fuels and contributing to environmental well-being. However, the inherent recalcitrance of biomass poses a significant obstacle to the efficient access of sugar polymers. Consequently, the bioconversion of lignocellulosic biomass into fermentable sugars remains a prominent challenge in biorefinery processes to produce biofuels and biochemicals. In addressing these challenges, extensive efforts have been dedicated to mitigating biomass recalcitrance through diverse pretreatment methods. One noteworthy process is Ammonia Fiber Expansion (AFEX) pretreatment, characterized by its dry-to-dry nature and minimal water usage. The volatile ammonia, acting as a catalyst in the process, is recyclable. AFEX contributes to cleaning biomass ester linkages and facilitating the opening of cell wall structures, enhancing enzyme accessibility and leading to a fivefold increase in sugar conversion compared to untreated biomass. Over the last decade, AFEX has demonstrated substantial success in augmenting the efficiency of biomass conversion processes. This success has unlocked the potential for sustainable and economically viable biorefineries. This paper offers a comprehensive review of studies focusing on the utilization of AFEX-pretreated biomass in the production of second-generation biofuels, ruminant feed, and additional value-added bioproducts like enzymes, lipids, proteins, and mushrooms. It delves into the details of the AFEX pretreatment process at both laboratory and pilot scales, elucidates the mechanism of action, and underscores the role of AFEX in the biorefinery for developing biofuels and bioproducts, and nutritious ruminant animal feed production. While highlighting the strides made, the paper also addresses current challenges in the commercialization of AFEX pretreatment within biorefineries. Furthermore, it outlines critical considerations that must be addressed to overcome these challenges, ensuring the continued progress and widespread adoption of AFEX in advancing sustainable and economically viable bio-based industries.
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Affiliation(s)
- Maedeh Mohammadi
- Department of Engineering Technology, Cullen College of Engineering, University of Houston, Sugarland, TX 77479, USA
| | - Mahsa Alian
- Department of Engineering Technology, Cullen College of Engineering, University of Houston, Sugarland, TX 77479, USA
| | - Bruce Dale
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA
| | - Bryan Ubanwa
- Department of Engineering Technology, Cullen College of Engineering, University of Houston, Sugarland, TX 77479, USA
| | - Venkatesh Balan
- Department of Engineering Technology, Cullen College of Engineering, University of Houston, Sugarland, TX 77479, USA.
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2
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Lee DS, Song Y, Lee YG, Bae HJ. Comparative Evaluation of Adsorption of Major Enzymes in a Cellulase Cocktail Obtained from Trichoderma reesei onto Different Types of Lignin. Polymers (Basel) 2022; 14:polym14010167. [PMID: 35012188 PMCID: PMC8747337 DOI: 10.3390/polym14010167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 02/04/2023] Open
Abstract
Cellulase adsorption onto lignin decreases the productivity of enzymatic hydrolysis of lignocellulosic biomass. Here, adsorption of enzymes onto different types of lignin was investigated, and the five major enzymes—cellobiohydrolases (CBHs), endoglucanase (Cel7B), β-glucosidase (Cel3A), xylanase (XYNIV), and mannanase (Man5A)—in a cellulase cocktail obtained from Trichoderma reesei were individually analyzed through SDS-PAGE and zymogram assay. Lignin was isolated from woody (oak and pine lignin) and herbaceous (rice straw and kenaf lignin) plants. The relative adsorption of CBHs compared to the control was in the range of 14.15–18.61%. The carbohydrate binding motif (CBM) of the CBHs contributed to higher adsorption levels in oak and kenaf lignin, compared to those in pine and rice lignin. The adsorption of endoglucanase (Cel7B) by herbaceous plant lignin was two times higher than that of woody lignin, whereas XYNIV showed the opposite pattern. β-glucosidase (Cel3A) displayed the highest and lowest adsorption ratios on rice straw and kenaf lignin, respectively. Mannanase (Man5A) was found to have the lowest adsorption ratio on pine lignin. Our results showed that the hydrophobic properties of CBM and the enzyme structures are key factors in adsorption onto lignin, whereas the properties of specific lignin types indirectly affect adsorption.
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Affiliation(s)
- Dae-Seok Lee
- Bio-Energy Research Center, Chonnam National University, Gwangju 500-575, Korea; (D.-S.L.); (Y.S.)
| | - Younho Song
- Bio-Energy Research Center, Chonnam National University, Gwangju 500-575, Korea; (D.-S.L.); (Y.S.)
| | - Yoon-Gyo Lee
- Department of Wood Science and Landscape Architecture, Chonnam National University, Gwangju 500-757, Korea;
| | - Hyeun-Jong Bae
- Bio-Energy Research Center, Chonnam National University, Gwangju 500-575, Korea; (D.-S.L.); (Y.S.)
- Department of Bioenergy Science and Technology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea
- Correspondence: ; Tel.: +81-62-530-2097
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3
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Chundawat SPS, Nemmaru B, Hackl M, Brady SK, Hilton MA, Johnson MM, Chang S, Lang MJ, Huh H, Lee SH, Yarbrough JM, López CA, Gnanakaran S. Molecular origins of reduced activity and binding commitment of processive cellulases and associated carbohydrate-binding proteins to cellulose III. J Biol Chem 2021; 296:100431. [PMID: 33610545 PMCID: PMC8010709 DOI: 10.1016/j.jbc.2021.100431] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 02/11/2021] [Accepted: 02/16/2021] [Indexed: 11/30/2022] Open
Abstract
Efficient enzymatic saccharification of cellulosic biomass into fermentable sugars can enable production of bioproducts like ethanol. Native crystalline cellulose, or cellulose I, is inefficiently processed via enzymatic hydrolysis but can be converted into the structurally distinct cellulose III allomorph that is processed via cellulase cocktails derived from Trichoderma reesei up to 20-fold faster. However, characterization of individual cellulases from T. reesei, like the processive exocellulase Cel7A, shows reduced binding and activity at low enzyme loadings toward cellulose III. To clarify this discrepancy, we monitored the single-molecule initial binding commitment and subsequent processive motility of Cel7A enzymes and associated carbohydrate-binding modules (CBMs) on cellulose using optical tweezers force spectroscopy. We confirmed a 48% lower initial binding commitment and 32% slower processive motility of Cel7A on cellulose III, which we hypothesized derives from reduced binding affinity of the Cel7A binding domain CBM1. Classical CBM–cellulose pull-down assays, depending on the adsorption model fitted, predicted between 1.2- and 7-fold reduction in CBM1 binding affinity for cellulose III. Force spectroscopy measurements of CBM1–cellulose interactions, along with molecular dynamics simulations, indicated that previous interpretations of classical binding assay results using multisite adsorption models may have complicated analysis, and instead suggest simpler single-site models should be used. These findings were corroborated by binding analysis of other type-A CBMs (CBM2a, CBM3a, CBM5, CBM10, and CBM64) on both cellulose allomorphs. Finally, we discuss how complementary analytical tools are critical to gain insight into the complex mechanisms of insoluble polysaccharides hydrolysis by cellulolytic enzymes and associated carbohydrate-binding proteins.
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Affiliation(s)
- Shishir P S Chundawat
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA.
| | - Bhargava Nemmaru
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Markus Hackl
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Sonia K Brady
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Mark A Hilton
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Madeline M Johnson
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Sungrok Chang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Hyun Huh
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Sang-Hyuk Lee
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - John M Yarbrough
- Biosciences Center, National Renewable Energy Lab, Golden, Colorado, USA
| | - Cesar A López
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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Nemmaru B, Ramirez N, Farino CJ, Yarbrough JM, Kravchenko N, Chundawat SPS. Reduced type-A carbohydrate-binding module interactions to cellulose I leads to improved endocellulase activity. Biotechnol Bioeng 2020; 118:1141-1151. [PMID: 33245142 DOI: 10.1002/bit.27637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/24/2022]
Abstract
Dissociation of nonproductively bound cellulolytic enzymes from cellulose is hypothesized to be a key rate-limiting factor impeding cost-effective biomass conversion to fermentable sugars. However, the role of carbohydrate-binding modules (CBMs) in enabling nonproductive enzyme binding is not well understood. Here, we examine the subtle interplay of CBM binding and cellulose hydrolysis activity for three models type-A CBMs (Families 1, 3a, and 64) tethered to multifunctional endoglucanase (CelE) on two distinct cellulose allomorphs (i.e., cellulose I and III). We generated a small library of mutant CBMs with varying cellulose affinity, as determined by equilibrium binding assays, followed by monitoring cellulose hydrolysis activity of CelE-CBM fusion constructs. Finally, kinetic binding assays using quartz crystal microbalance with dissipation were employed to measure CBM adsorption and desorption rate constants k on and k off , respectively, towards nanocrystalline cellulose derived from both allomorphs. Overall, our results indicate that reduced CBM equilibrium binding affinity towards cellulose I alone, resulting from increased desorption rates ( k off ) and reduced effective adsorption rates ( nk on ), is correlated to overall improved endocellulase activity. Future studies could employ similar approaches to unravel the role of CBMs in nonproductive enzyme binding and develop improved cellulolytic enzymes for industrial applications.
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Affiliation(s)
| | - Nicholas Ramirez
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Cindy J Farino
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - John M Yarbrough
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Nicholas Kravchenko
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Shishir P S Chundawat
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
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Yuan Y, Zhai R, Li Y, Chen X, Jin M. Developing fast enzyme recycling strategy through elucidating enzyme adsorption kinetics on alkali and acid pretreated corn stover. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:316. [PMID: 30479661 PMCID: PMC6245881 DOI: 10.1186/s13068-018-1315-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/08/2018] [Indexed: 06/01/2023]
Abstract
BACKGROUND Although various pre-treatment methods have been developed to disrupt the structure of lignocellulosic biomass, high dosage of cellulases is still required to hydrolyze lignocellulose to fermentable sugars. Enzyme recycling via recycling unhydrolyzed solids after enzymatic hydrolysis is a promising strategy to reduce enzyme loading for production of cellulosic ethanol. RESULTS To develop effective enzyme recycling method via recycling unhydrolyzed solids, this work investigated both enzymatic hydrolysis kinetics and enzyme adsorption kinetics on dilute acid and dilute alkali pre-treated corn stover (CS). It was found that most of the hydrolysable biomass was hydrolyzed in the first 24 h and about 40% and 55% of the enzymes were adsorbed on unhydrolyzed solids for dilute alkali-CS and dilute acid-CS, respectively, at 24 h of enzymatic hydrolysis. Lignin played a significant role in such adsorption and lignin materials derived from dilute acid-CS and dilute alkali-CS possessed different enzyme adsorption properties. Enzyme recycling was performed by recycling unhydrolyzed solids after 24 h enzymatic hydrolysis for five successive rounds, and successfully reduced 40% and 50% of the enzyme loadings for hydrolysis of dilute alkali-CS and for hydrolysis of dilute acid-CS, respectively. CONCLUSIONS This study presents that the enzymes adsorbed on the unhydrolyzed solids after short-time hydrolysis could be recycled effectively for efficient enzymatic hydrolysis. Lignin derived from dilute acid-CS has higher enzyme adsorption capacity than the lignin derived from dilute alkali-CS, which led to more enzymes recycled. By applying the enzyme recycling strategy developed in this study, the enzyme dosage needed for effective cellulose hydrolysis can be significantly reduced.
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Affiliation(s)
- Ye Yuan
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094 China
| | - Rui Zhai
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094 China
| | - Ying Li
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094 China
| | - Xiangxue Chen
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094 China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing, 210094 China
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Li J, Lu M, Guo X, Zhang H, Li Y, Han L. Insights into the improvement of alkaline hydrogen peroxide (AHP) pretreatment on the enzymatic hydrolysis of corn stover: Chemical and microstructural analyses. BIORESOURCE TECHNOLOGY 2018; 265:1-7. [PMID: 29860078 DOI: 10.1016/j.biortech.2018.05.082] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/21/2018] [Accepted: 05/22/2018] [Indexed: 06/08/2023]
Abstract
The alkaline hydrogen peroxide (AHP) pretreatment (0.5 g H2O2/g corn stover, 30 °C, 24 h) removed 91.53% of the initial lignin and 55.77% of the initial hemicellulose in corn stover and afforded a considerable glucose yield (88.34%) through enzymatic hydrolysis. A combination of chemical and microstructural analyses was used to illustrate the mechanism of the effect of AHP pretreatment on enzymatic hydrolysis. During pretreatment, H2O2-derived radicals effectively spread into and destroyed the cell wall of various parts (vascular bundle sheath, xylem vessels, tracheid, phloem, and parenchyma) of corn stover to remove most of the lignin, acetyl group, and partial hemicellulose. They destroyed the compact structure of the cellulose-hemicellulose-lignin network, increased the cellulase-accessible pore volume by 6 times, doubled the area of exposed cellulose, and decreased the unproductive adsorption of enzymes onto lignin. Combining all the effects, AHP pretreatment effectively improved the cellulose accessibility to enhance the subsequent enzymatic hydrolysis efficiency.
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Affiliation(s)
- Junbao Li
- College of Engineering, China Agricultural University (East Campus), 17 Qing-Hua-Dong-Lu, Hai-Dian District, Beijing 100083, PR China
| | - Minsheng Lu
- College of Engineering, China Agricultural University (East Campus), 17 Qing-Hua-Dong-Lu, Hai-Dian District, Beijing 100083, PR China
| | - Xiaomiao Guo
- College of Engineering, China Agricultural University (East Campus), 17 Qing-Hua-Dong-Lu, Hai-Dian District, Beijing 100083, PR China
| | - Haiyan Zhang
- College of Engineering, China Agricultural University (East Campus), 17 Qing-Hua-Dong-Lu, Hai-Dian District, Beijing 100083, PR China
| | - Yaping Li
- College of Engineering, China Agricultural University (East Campus), 17 Qing-Hua-Dong-Lu, Hai-Dian District, Beijing 100083, PR China
| | - Lujia Han
- College of Engineering, China Agricultural University (East Campus), 17 Qing-Hua-Dong-Lu, Hai-Dian District, Beijing 100083, PR China.
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7
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Anhydrous Ammonia Pretreatment of Corn Stover and Enzymatic Hydrolysis of Glucan from Pretreated Corn Stover. FERMENTATION-BASEL 2017. [DOI: 10.3390/fermentation3010009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Haarmeyer CN, Smith MD, Chundawat SPS, Sammond D, Whitehead TA. Insights into cellulase-lignin non-specific binding revealed by computational redesign of the surface of green fluorescent protein. Biotechnol Bioeng 2016; 114:740-750. [DOI: 10.1002/bit.26201] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/09/2016] [Accepted: 10/10/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Carolyn N. Haarmeyer
- Department of Chemical Engineering and Materials Science; Michigan State University; East Lansing Michigan 48824
| | - Matthew D. Smith
- Department of Chemical Engineering and Materials Science; Michigan State University; East Lansing Michigan 48824
| | - Shishir P. S Chundawat
- Great Lakes Bioenergy Research Center (GLBRC); Michigan State University; East Lansing Michigan
- Department of Chemical and Biochemical Engineering; Rutgers; The State University of New Jersey; Piscataway New Jersey
| | - Deanne Sammond
- Biosciences Center; National Renewable Energy Laboratory; Golden Colorado
| | - Timothy A. Whitehead
- Department of Chemical Engineering and Materials Science; Michigan State University; East Lansing Michigan 48824
- Department of Biosystems and Agricultural Engineering; Michigan State University; East Lansing Michigan 48824
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Arora A, Priya S, Sharma P, Sharma S, Nain L. Evaluating biological pretreatment as a feasible methodology for ethanol production from paddy straw. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2016. [DOI: 10.1016/j.bcab.2016.08.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Nwaneshiudu IC, Ganguly I, Pierobon F, Bowers T, Eastin I. Environmental assessment of mild bisulfite pretreatment of forest residues into fermentable sugars for biofuel production. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:15. [PMID: 26807148 PMCID: PMC4722614 DOI: 10.1186/s13068-016-0433-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/08/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Sugar production via pretreatment and enzymatic hydrolysis of cellulosic feedstock, in this case softwood harvest residues, is a critical step in the biochemical conversion pathway towards drop-in biofuels. Mild bisulfite (MBS) pretreatment is an emerging option for the breakdown and subsequent processing of biomass towards fermentable sugars. An environmental assessment of this process is critical to discern its future sustainability in the ever-changing biofuels landscape. RESULTS The subsequent cradle-to-gate assessment of a proposed sugar production facility analyzes sugar made from woody biomass using MBS pretreatment across all seven impact categories (functional unit 1 kg dry mass sugar), with a specific focus on potential global warming and eutrophication impacts. The study found that the eutrophication impact (0.000201 kg N equivalent) is less than the impacts from conventional beet and cane sugars, while the global warming impact (0.353 kg CO2 equivalent) falls within the range of conventional processes. CONCLUSIONS This work discusses some of the environmental impacts of designing and operating a sugar production facility that uses MBS as a method of treating cellulosic forest residuals. The impacts of each unit process in the proposed facility are highlighted. A comparison to other sugar-making process is detailed and will inform the growing biofuels literature.
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Affiliation(s)
- Ikechukwu C. Nwaneshiudu
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Indroneil Ganguly
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Francesca Pierobon
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Tait Bowers
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Ivan Eastin
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
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Niu H, Shah N, Kontoravdi C. Modelling of amorphous cellulose depolymerisation by cellulases, parametric studies and optimisation. Biochem Eng J 2016; 105:455-472. [PMID: 26865832 PMCID: PMC4705870 DOI: 10.1016/j.bej.2015.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A mechanistic model for heterogeneous cellulose hydrolysis by cellulases. A modeling framework for uncertainty analysis, model reduction and refinement. The parameters were estimated. Composition of cellulases cocktail was optimized using the model.
Improved understanding of heterogeneous cellulose hydrolysis by cellulases is the basis for optimising enzymatic catalysis-based cellulosic biorefineries. A detailed mechanistic model is developed to describe the dynamic adsorption/desorption and synergistic chain-end scissions of cellulases (endoglucanase, exoglucanase, and β-glucosidase) upon amorphous cellulose. The model can predict evolutions of the chain lengths of insoluble cellulose polymers and production of soluble sugars during hydrolysis. Simultaneously, a modelling framework for uncertainty analysis is built based on a quasi-Monte-Carlo method and global sensitivity analysis, which can systematically identify key parameters, help refine the model and improve its identifiability. The model, initially comprising 27 parameters, is found to be over-parameterized with structural and practical identification problems under usual operating conditions (low enzyme loadings). The parameter estimation problem is therefore mathematically ill posed. The framework allows us, on the one hand, to identify a subset of 13 crucial parameters, of which more accurate confidence intervals are estimated using a given experimental dataset, and, on the other hand, to overcome the identification problems. The model’s predictive capability is checked against an independent set of experimental data. Finally, the optimal composition of cellulases cocktail is obtained by model-based optimisation both for enzymatic hydrolysis and for the process of simultaneous saccharification and fermentation.
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Affiliation(s)
- Hongxing Niu
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK
| | - Nilay Shah
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK
| | - Cleo Kontoravdi
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK
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12
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Engineering the hydrophobic residues of a GH11 xylanase impacts its adsorption onto lignin and its thermostability. Enzyme Microb Technol 2015; 81:47-55. [DOI: 10.1016/j.enzmictec.2015.07.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/24/2015] [Accepted: 07/25/2015] [Indexed: 11/23/2022]
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13
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Sideney BO, Zipora MQS, Francini YK, Shaiana PM. Cellulases produced by the endophytic fungus Pycnoporus sanguineus (L.) Murrill. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/ajar2015.9487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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14
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Vermaas JV, Petridis L, Qi X, Schulz R, Lindner B, Smith JC. Mechanism of lignin inhibition of enzymatic biomass deconstruction. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:217. [PMID: 26697106 PMCID: PMC4687093 DOI: 10.1186/s13068-015-0379-8] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/09/2015] [Indexed: 05/06/2023]
Abstract
BACKGROUND The conversion of plant biomass to ethanol via enzymatic cellulose hydrolysis offers a potentially sustainable route to biofuel production. However, the inhibition of enzymatic activity in pretreated biomass by lignin severely limits the efficiency of this process. RESULTS By performing atomic-detail molecular dynamics simulation of a biomass model containing cellulose, lignin, and cellulases (TrCel7A), we elucidate detailed lignin inhibition mechanisms. We find that lignin binds preferentially both to the elements of cellulose to which the cellulases also preferentially bind (the hydrophobic faces) and also to the specific residues on the cellulose-binding module of the cellulase that are critical for cellulose binding of TrCel7A (Y466, Y492, and Y493). CONCLUSIONS Lignin thus binds exactly where for industrial purposes it is least desired, providing a simple explanation of why hydrolysis yields increase with lignin removal.
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Affiliation(s)
- Josh V. Vermaas
- />UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 37831 Oak Ridge, TN USA
- />Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 61801 Urbana, IL USA
| | - Loukas Petridis
- />UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 37831 Oak Ridge, TN USA
| | - Xianghong Qi
- />UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 37831 Oak Ridge, TN USA
- />Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 37996 Knoxville, TN USA
| | - Roland Schulz
- />UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 37831 Oak Ridge, TN USA
- />Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 37996 Knoxville, TN USA
| | - Benjamin Lindner
- />UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 37831 Oak Ridge, TN USA
| | - Jeremy. C. Smith
- />UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, 37831 Oak Ridge, TN USA
- />Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 37996 Knoxville, TN USA
- />University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, P.O.Box 2008, Oak Ridge, TN 37831-6309 USA
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15
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Xue S, Uppugundla N, Bowman MJ, Cavalier D, Da Costa Sousa L, E Dale B, Balan V. Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:195. [PMID: 26617670 PMCID: PMC4662034 DOI: 10.1186/s13068-015-0378-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/09/2015] [Indexed: 05/03/2023]
Abstract
BACKGROUND Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18-25 % of the total soluble sugars in the hydrolysate and 12-18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7-9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production from cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. RESULTS Oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEX-corn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the inhibitory effects of oligosaccharides on commercial enzymes. CONCLUSION The carbohydrate composition of the recalcitrant oligosaccharides, ratios of different DP oligomers and their distribution profiles were determined. Recalcitrance and enzyme inhibition studies help determine whether the commercial enzyme mixtures lack the enzyme activities required to completely de-polymerize the plant cell wall. Such studies clarify the reasons for oligosaccharide accumulation and contribute to strategies by which oligosaccharides can be converted into fermentable sugars and provide higher biofuel yields with less enzyme.
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Affiliation(s)
- Saisi Xue
- />DOE Great Lakes Bioenergy Research Center, Biomass Conversion Research Lab (BCRL), Chemical Engineering and Materials Science, Michigan State University, 3815 Technology Boulevard, Lansing, MI 48910 USA
| | - Nirmal Uppugundla
- />DOE Great Lakes Bioenergy Research Center, Biomass Conversion Research Lab (BCRL), Chemical Engineering and Materials Science, Michigan State University, 3815 Technology Boulevard, Lansing, MI 48910 USA
| | - Michael J. Bowman
- />USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Bioenergy Research Unit, Peoria, IL 61604 USA
| | - David Cavalier
- />DOE Great Lakes Bioenergy Research Center, Biomass Conversion Research Lab (BCRL), Chemical Engineering and Materials Science, Michigan State University, 3815 Technology Boulevard, Lansing, MI 48910 USA
- />DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
| | - Leonardo Da Costa Sousa
- />DOE Great Lakes Bioenergy Research Center, Biomass Conversion Research Lab (BCRL), Chemical Engineering and Materials Science, Michigan State University, 3815 Technology Boulevard, Lansing, MI 48910 USA
| | - Bruce. E Dale
- />DOE Great Lakes Bioenergy Research Center, Biomass Conversion Research Lab (BCRL), Chemical Engineering and Materials Science, Michigan State University, 3815 Technology Boulevard, Lansing, MI 48910 USA
| | - Venkatesh Balan
- />DOE Great Lakes Bioenergy Research Center, Biomass Conversion Research Lab (BCRL), Chemical Engineering and Materials Science, Michigan State University, 3815 Technology Boulevard, Lansing, MI 48910 USA
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Greene ER, Himmel ME, Beckham GT, Tan Z. Glycosylation of Cellulases: Engineering Better Enzymes for Biofuels. Adv Carbohydr Chem Biochem 2015; 72:63-112. [PMID: 26613815 DOI: 10.1016/bs.accb.2015.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cellulose in plant cell walls is the largest reservoir of renewable carbon on Earth. The saccharification of cellulose from plant biomass into soluble sugars can be achieved using fungal and bacterial cellulolytic enzymes, cellulases, and further converted into fuels and chemicals. Most fungal cellulases are both N- and O-glycosylated in their native form, yet the consequences of glycosylation on activity and structure are not fully understood. Studying protein glycosylation is challenging as glycans are extremely heterogeneous, stereochemically complex, and glycosylation is not under direct genetic control. Despite these limitations, many studies have begun to unveil the role of cellulase glycosylation, especially in the industrially relevant cellobiohydrolase from Trichoderma reesei, Cel7A. Glycosylation confers many beneficial properties to cellulases including enhanced activity, thermal and proteolytic stability, and structural stabilization. However, glycosylation must be controlled carefully as such positive effects can be dampened or reversed. Encouragingly, methods for the manipulation of glycan structures have been recently reported that employ genetic tuning of glycan-active enzymes expressed from homogeneous and heterologous fungal hosts. Taken together, these studies have enabled new strategies for the exploitation of protein glycosylation for the production of enhanced cellulases for biofuel production.
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Gao D, Haarmeyer C, Balan V, Whitehead TA, Dale BE, Chundawat SPS. Lignin triggers irreversible cellulase loss during pretreated lignocellulosic biomass saccharification. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:175. [PMID: 25530803 PMCID: PMC4272552 DOI: 10.1186/s13068-014-0175-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/27/2014] [Indexed: 05/02/2023]
Abstract
BACKGROUND Non-productive binding of enzymes to lignin is thought to impede the saccharification efficiency of pretreated lignocellulosic biomass to fermentable sugars. Due to a lack of suitable analytical techniques that track binding of individual enzymes within complex protein mixtures and the difficulty in distinguishing the contribution of productive (binding to specific glycans) versus non-productive (binding to lignin) binding of cellulases to lignocellulose, there is currently a poor understanding of individual enzyme adsorption to lignin during the time course of pretreated biomass saccharification. RESULTS In this study, we have utilized an FPLC (fast protein liquid chromatography)-based methodology to quantify free Trichoderma reesei cellulases (namely CBH I, CBH II, and EG I) concentration within a complex hydrolyzate mixture during the varying time course of biomass saccharification. Three pretreated corn stover (CS) samples were included in this study: Ammonia Fiber Expansion(a) (AFEX™-CS), dilute acid (DA-CS), and ionic liquid (IL-CS) pretreatments. The relative fraction of bound individual cellulases varied depending not only on the pretreated biomass type (and lignin abundance) but also on the type of cellulase. Acid pretreated biomass had the highest levels of non-recoverable cellulases, while ionic liquid pretreated biomass had the highest overall cellulase recovery. CBH II has the lowest thermal stability among the three T. reesei cellulases tested. By preparing recombinant family 1 carbohydrate binding module (CBM) fusion proteins, we have shown that family 1 CBMs are highly implicated in the non-productive binding of full-length T. reesei cellulases to lignin. CONCLUSIONS Our findings aid in further understanding the complex mechanisms of non-productive binding of cellulases to pretreated lignocellulosic biomass. Developing optimized pretreatment processes with reduced or modified lignin content to minimize non-productive enzyme binding or engineering pretreatment-specific, low-lignin binding cellulases will improve enzyme specific activity, facilitate enzyme recycling, and thereby permit production of cheaper biofuels.
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Affiliation(s)
- Dahai Gao
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 USA
- />Great Lakes Bioenergy Research Center (GLBRC), Michigan State University, 164 Food Safety and Toxicology Building, East Lansing, MI 48824 USA
- />Biomass Conversion Research Lab (BCRL), MBI Building, 3900 Collins Road, East Lansing, MI 48910 USA
| | - Carolyn Haarmeyer
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 USA
| | - Venkatesh Balan
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 USA
- />Great Lakes Bioenergy Research Center (GLBRC), Michigan State University, 164 Food Safety and Toxicology Building, East Lansing, MI 48824 USA
- />Biomass Conversion Research Lab (BCRL), MBI Building, 3900 Collins Road, East Lansing, MI 48910 USA
| | - Timothy A Whitehead
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 USA
- />Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824 USA
| | - Bruce E Dale
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 USA
- />Great Lakes Bioenergy Research Center (GLBRC), Michigan State University, 164 Food Safety and Toxicology Building, East Lansing, MI 48824 USA
- />Biomass Conversion Research Lab (BCRL), MBI Building, 3900 Collins Road, East Lansing, MI 48910 USA
| | - Shishir PS Chundawat
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 USA
- />Great Lakes Bioenergy Research Center (GLBRC), Michigan State University, 164 Food Safety and Toxicology Building, East Lansing, MI 48824 USA
- />Biomass Conversion Research Lab (BCRL), MBI Building, 3900 Collins Road, East Lansing, MI 48910 USA
- />Department of Chemical & Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Room C-150A, Piscataway, NJ 08854 USA
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Current challenges in commercially producing biofuels from lignocellulosic biomass. ISRN BIOTECHNOLOGY 2014; 2014:463074. [PMID: 25937989 PMCID: PMC4393053 DOI: 10.1155/2014/463074] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 02/19/2014] [Indexed: 11/17/2022]
Abstract
Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be produced in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected.
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Anderson LN, Culley DE, Hofstad BA, Chauvigné-Hines LM, Zink EM, Purvine SO, Smith RD, Callister SJ, Magnuson JM, Wright AT. Activity-based protein profiling of secreted cellulolytic enzyme activity dynamics in Trichoderma reesei QM6a, NG14, and RUT-C30. MOLECULAR BIOSYSTEMS 2013; 9:2992-3000. [PMID: 24121482 DOI: 10.1039/c3mb70333a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lignocellulosic biomass has great promise as a highly abundant and renewable source for the production of biofuels. However, the recalcitrant nature of lignocellulose toward hydrolysis into soluble sugars remains a significant challenge to harnessing the potential of this source of bioenergy. A primary method for deconstructing lignocellulose is via chemical treatments, high temperatures, and hydrolytic enzyme cocktails, many of which are derived from the fungus Trichoderma reesei. Herein, we use an activity-based probe for glycoside hydrolases to rapidly identify optimal conditions for maximum enzymatic lignocellulose deconstruction. We also demonstrate that subtle changes to enzyme composition and activity in various strains of T. reesei can be readily characterized by our probe approach. The approach also permits multimodal measurements, including fluorescent gel-based analysis of activity in response to varied conditions and treatments, and mass spectrometry-based quantitative identification of labelled proteins. We demonstrate the promise this probe approach holds to facilitate rapid production of enzyme cocktails for high-efficiency lignocellulose deconstruction to accommodate high-yield biofuel production.
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Affiliation(s)
- Lindsey N Anderson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA.
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20
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Increased enzyme binding to substrate is not necessary for more efficient cellulose hydrolysis. Proc Natl Acad Sci U S A 2013; 110:10922-7. [PMID: 23784776 DOI: 10.1073/pnas.1213426110] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Substrate binding is typically one of the rate-limiting steps preceding enzyme catalytic action during homogeneous reactions. However, interfacial-based enzyme catalysis on insoluble crystalline substrates, like cellulose, has additional bottlenecks of individual biopolymer chain decrystallization from the substrate interface followed by its processive depolymerization to soluble sugars. This additional decrystallization step has ramifications on the role of enzyme-substrate binding and its relationship to overall catalytic efficiency. We found that altering the crystalline structure of cellulose from its native allomorph I(β) to III(I) results in 40-50% lower binding partition coefficient for fungal cellulases, but surprisingly, it enhanced hydrolytic activity on the latter allomorph. We developed a comprehensive kinetic model for processive cellulases acting on insoluble substrates to explain this anomalous finding. Our model predicts that a reduction in the effective binding affinity to the substrate coupled with an increase in the decrystallization procession rate of individual cellulose chains from the substrate surface into the enzyme active site can reproduce our anomalous experimental findings.
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21
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Pribowo AY, Hu J, Arantes V, Saddler JN. The development and use of an ELISA-based method to follow the distribution of cellulase monocomponents during the hydrolysis of pretreated corn stover. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:80. [PMID: 23687947 PMCID: PMC3666928 DOI: 10.1186/1754-6834-6-80] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/10/2013] [Indexed: 05/11/2023]
Abstract
BACKGROUND It is widely recognised that fast, effective hydrolysis of pretreated lignocellulosic substrates requires the synergistic action of multiple types of hydrolytic and some non-hydrolytic proteins. However, due to the complexity of the enzyme mixture, the enzymes interaction with and interference from the substrate and a lack of specific methods to follow the distribution of individual enzymes during hydrolysis, most of enzyme-substrate interaction studies have used purified enzymes and pure cellulose model substrates. As the enzymes present in a typical "cellulase mixture" need to work cooperatively to achieve effective hydrolysis, the action of one enzyme is likely to influence the behaviour of others. The action of the enzymes will be further influenced by the nature of the lignocellulosic substrate. Therefore, it would be beneficial if a method could be developed that allowed us to follow some of the individual enzymes present in a cellulase mixture during hydrolysis of more commercially realistic biomass substrates. RESULTS A high throughput immunoassay that could quantitatively and specifically follow individual cellulase enzymes during hydrolysis was developed. Using monoclonal and polyclonal antibodies (MAb and PAb, respectively), a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed to specifically quantify cellulase enzymes from Trichoderma reesei: cellobiohydrolase I (Cel7A), cellobiohydrolase II (Cel6A), and endoglucanase I (Cel7B). The interference from substrate materials present in lignocellulosic supernatants could be minimized by dilution. CONCLUSION A double-antibody sandwich ELISA was able to detect and quantify individual enzymes when present in cellulase mixtures. The assay was sensitive over a range of relatively low enzyme concentration (0 - 1 μg/ml), provided the enzymes were first pH adjusted and heat treated to increase their antigenicity. The immunoassay was employed to quantitatively monitor the adsorption of cellulase monocomponents, Cel7A, Cel6A, and Cel7B, that were present in both Celluclast and Accellerase 1000, during the hydrolysis of steam-pretreated corn stover (SPCS). All three enzymes exhibited different individual adsorption profiles. The specific and quantitative adsorption profiles observed with the ELISA method were in agreement with earlier work where more labour intensive enzyme assay techniques were used.
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Affiliation(s)
- Amadeus Y Pribowo
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, V6T1Z4, Canada
| | - Jinguang Hu
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, V6T1Z4, Canada
| | - Valdeir Arantes
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, V6T1Z4, Canada
| | - Jack N Saddler
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, V6T1Z4, Canada
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Nonaka H, Kobayashi A, Funaoka M. Behavior of lignin-binding cellulase in the presence of fresh cellulosic substrate. BIORESOURCE TECHNOLOGY 2013; 135:53-57. [PMID: 23186657 DOI: 10.1016/j.biortech.2012.10.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 10/12/2012] [Accepted: 10/13/2012] [Indexed: 05/18/2023]
Abstract
A model lignin-binding cellulase was prepared from Trichoderma reesei cellulase and lignocresol, which was synthesized from softwood or hardwood lignin. Filter paper was incubated with the lignocresol-cellulase complex, and it was observed that only a limited amount of cellulase migrated to the filter paper. The cellulase adsorption isotherms for the lignocresols and filter paper were fitted to a Langmuir absorption model, and the determined Langmuir constants were as follows: softwood lignocresol>hardwood lignocresol>>filter paper. The calculations demonstrated that lignin-binding cellulase can potentially be recovered by the addition of a sufficient quantity of cellulosic substrate. As a result, the lignocresol-binding cellulase is highly stable and lignocresol can potentially be used for immobilizing cellulase in the active state.
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Affiliation(s)
- Hiroshi Nonaka
- Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan.
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Zeder-Lutz G, Renau-Ferrer S, Aguié-Béghin V, Rakotoarivonina H, Chabbert B, Altschuh D, Rémond C. Novel surface-based methodologies for investigating GH11 xylanase–lignin derivative interactions. Analyst 2013; 138:6889-99. [DOI: 10.1039/c3an00772c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Matano Y, Hasunuma T, Kondo A. Simultaneous improvement of saccharification and ethanol production from crystalline cellulose by alleviation of irreversible adsorption of cellulase with a cell surface-engineered yeast strain. Appl Microbiol Biotechnol 2012. [DOI: 10.1007/s00253-012-4587-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Zhang T, Wyman CE, Jakob K, Yang B. Rapid selection and identification of Miscanthus genotypes with enhanced glucan and xylan yields from hydrothermal pretreatment followed by enzymatic hydrolysis. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:56. [PMID: 22863302 PMCID: PMC3494522 DOI: 10.1186/1754-6834-5-56] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 06/20/2012] [Indexed: 05/02/2023]
Abstract
BACKGROUND Because many Miscanthus genotypes can be cultivated with relatively high productivity and carbohydrate content, Miscanthus has great potential as an energy crop that can support large scale biological production of biofuels. RESULTS In this study, batch hydrothermal pretreatment at 180°C for 35 min followed by enzymatic hydrolysis was shown to give the highest total sugar yields for Miscanthus x giganteus cv. Illinois planted in Illinois. High throughput pretreatment at 180°C for 35 min and 17.5 min followed by co-hydrolysis in a multi-well batch reactor identified two varieties out of 80 that had significantly higher sugar yields from pretreatment and enzymatic hydrolysis than others. The differences in performance were then related to compositions of the 80 varieties to provide insights into desirable traits for Miscanthus that enhance sugar yields. CONCLUSIONS High throughput pretreatment and co-hydrolysis (HTPH) rapidly identified promising genotypes from a wide range of Miscanthus genotypes, including hybrids of Miscanthus sacchariflorus/M. sinensis and Miscanthus lutarioriparius, differentiating the more commercially promising species from the rest. The total glucan plus xylan content in Miscanthus appeared to influence both mass and theoretical yields, while lignin and ash contents did not have a predictable influence on performance.
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Affiliation(s)
- Taiying Zhang
- Center for Environmental Research and Technology, Bourns College of Engineering, University of California, 1084 Columbia Avenue, Riverside, CA, 92507, USA
| | - Charles E Wyman
- Center for Environmental Research and Technology, Bourns College of Engineering, University of California, 1084 Columbia Avenue, Riverside, CA, 92507, USA
- Chemical and Environmental Engineering Department, Bourns College of Engineering, University of California, Riverside, CA, 92521, USA
| | - Katrin Jakob
- Mendel Biotechnology Inc., 3935 Point Eden Way, Hayward, CA, 94545, USA
| | - Bin Yang
- Center for Environmental Research and Technology, Bourns College of Engineering, University of California, 1084 Columbia Avenue, Riverside, CA, 92507, USA
- Center for Bioproducts and Bioenergy, Washington State University, 2710 University Drive, Richland, WA, 99354, USA
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Chundawat SPS, Lipton MS, Purvine SO, Uppugundla N, Gao D, Balan V, Dale BE. Proteomics-based compositional analysis of complex cellulase-hemicellulase mixtures. J Proteome Res 2011; 10:4365-72. [PMID: 21678892 DOI: 10.1021/pr101234z] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Efficient deconstruction of cellulosic biomass to fermentable sugars for fuel and chemical production is accomplished by a complex mixture of cellulases, hemicellulases, and accessory enzymes (e.g., >50 extracellular proteins). Cellulolytic enzyme mixtures, produced industrially mostly using fungi like Trichoderma reesei, are poorly characterized in terms of their protein composition and its correlation to hydrolytic activity on cellulosic biomass. The secretomes of commercial glycosyl hydrolase-producing microbes was explored using a proteomics approach with high-throughput quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we show that proteomics-based spectral counting approach is a reasonably accurate and rapid analytical technique that can be used to determine protein composition of complex glycosyl hydrolase mixtures that also correlates with the specific activity of individual enzymes present within the mixture. For example, a strong linear correlation was seen between Avicelase activity and total cellobiohydrolase content. Reliable, quantitative and cheaper analytical methods that provide insight into the cellulosic biomass degrading fungal and bacterial secretomes would lead to further improvements toward commercialization of plant biomass-derived fuels and chemicals.
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Affiliation(s)
- Shishir P S Chundawat
- Biomass Conversion Research Laboratory, Chemical Engineering and Materials Science, Michigan State University , 3815 Technology Boulevard, Suite 1045, Lansing, Michigan 48910, United States.
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