1
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Pentari C, Zerva A, Kosinas C, Karampa P, Puchart V, Dimarogona M, Topakas E. The role of CE16 exo-deacetylases in hemicellulolytic enzyme mixtures revealed by the biochemical and structural study of the novel TtCE16B esterase. Carbohydr Polym 2024; 327:121667. [PMID: 38171682 DOI: 10.1016/j.carbpol.2023.121667] [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: 08/24/2023] [Revised: 12/03/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
Acetyl esterases belonging to the carbohydrate esterase family 16 (CE16) is a growing group of enzymes, with exceptional diversity regarding substrate specificity and regioselectivity. However, further insight into the CE16 specificity is required for their efficient biotechnological exploitation. In this work, exo-deacetylase TtCE16B from Thermothelomyces thermophila was heterologously expressed and biochemically characterized. The esterase targets positions O-3 and O-4 of singly and doubly acetylated non-reducing-end xylopyranosyl residues, provided the presence of a free vicinal hydroxyl group at position O-4 and O-3, respectively. Crystal structure of TtCE16B, the first representative among the CE16 enzymes, in apo- and product-bound form, allowed the identification of residues forming the catalytic triad and oxyanion hole, as well as the structural elements related to the enzyme preference for oligomers. The role of TtCE16B in hemicellulose degradation was investigated on acetylated xylan from birchwood and pre-treated beechwood biomass. TtCE16B exhibited complementary activity to commercially available OCE6 acetylxylan esterase. Moreover, it showed synergistic effects with SrXyl43 β-xylosidase. Overall, supplementation of xylan-targeting enzymatic mixtures with both TtCE16B and OCE6 esterases led to a 3-fold or 4-fold increase in xylose release, when using TmXyn10 and TtXyn30A xylanases respectively.
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Affiliation(s)
- Christina Pentari
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Anastasia Zerva
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece; Laboratory of Enzyme Technology, Department of Biotechnology, School of Applied Biology and Biotechnology, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens, Greece
| | - Christos Kosinas
- Laboratory of Structural Biology and Biotechnology, Department of Chemical Engineering, University of Patras, Patras, Greece
| | - Panagiota Karampa
- Laboratory of Structural Biology and Biotechnology, Department of Chemical Engineering, University of Patras, Patras, Greece
| | - Vladimír Puchart
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38 Bratislava, Slovak Republic
| | - Maria Dimarogona
- Laboratory of Structural Biology and Biotechnology, Department of Chemical Engineering, University of Patras, Patras, Greece.
| | - Evangelos Topakas
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
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2
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Kim S, Kim JC, Kim YY, Yang JE, Lee HM, Hwang IM, Park HW, Kim HM. Utilization of coffee waste as a sustainable feedstock for high-yield lactic acid production through microbial fermentation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169521. [PMID: 38141985 DOI: 10.1016/j.scitotenv.2023.169521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/27/2023] [Accepted: 12/17/2023] [Indexed: 12/25/2023]
Abstract
Lactic acid is an important industrial precursor; however, high substrate costs are a major challenge in microbial fermentation-based lactic acid production. Coffee waste is a sustainable feedstock alternative for lactic acid production via microbial fermentation. Herein, the feasibility of coffee waste as a feedstock was explored by employing appropriate pretreatment methods and optimizing enzyme combinations. Coffee waste pretreatment with hydrogen peroxide and acetic acid along with a combination of Viscozyme L, Celluclast 1.5 L, and Pectinex Ultra SP-L achieved the 78.9 % sugar conversion rate at a substrate concentration of 4 % (w/v). Lactiplantibacillus plantarum WiKim0126-induced fermentation with a 4 % solid loading yielded a lactic acid concentration of 22.8 g/L (99.6 % of the theoretical maximum yield) and productivity of 0.95 g/L/h within 24 h. These findings highlight the viability of coffee waste as an eco-friendly resource for sustainable lactic acid production.
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Affiliation(s)
- Seulbi Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea; Department of Agricultural Chemistry, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jong-Cheol Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Yeong Yeol Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea; Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jung Eun Yang
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Hee Min Lee
- Kimchi Industry Promotion Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
| | - In Min Hwang
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Hae Woong Park
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Ho Myeong Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju, Republic of Korea.
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3
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Zheng F, Basit A, Zhuang H, Chen J, Zhang J, Chen W. Biochemical characterization of a novel acidophilic β-xylanase from Trichoderma asperellum ND-1 and its synergistic hydrolysis of beechwood xylan. Front Microbiol 2022; 13:998160. [PMID: 36199370 PMCID: PMC9527580 DOI: 10.3389/fmicb.2022.998160] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/15/2022] [Indexed: 11/29/2022] Open
Abstract
Acidophilic β-xylanases have attracted considerable attention due to their excellent activity under extreme acidic environments and potential industrial utilizations. In this study, a novel β-xylanase gene (Xyl11) of glycoside hydrolase family 11, was cloned from Trichoderma asperellum ND-1 and efficiently expressed in Pichia pastoris (a 2.0-fold increase). Xyl11 displayed a maximum activity of 121.99 U/ml at pH 3.0 and 50°C, and exhibited strict substrate specificity toward beechwood xylan (Km = 9.06 mg/ml, Vmax = 608.65 μmol/min/mg). The Xyl11 retained over 80% activity at pH 2.0–5.0 after pretreatment at 4°C for 1 h. Analysis of the hydrolytic pattern revealed that Xyl11 could rapidly convert xylan to xylobiose via hydrolysis activity as well as transglycosylation. Moreover, the results of site-directed mutagenesis suggested that the Xyl11 residues, Glu127, Glu164, and Glu216, are essential catalytic sites, with Asp138 having an auxiliary function. Additionally, a high degree of synergy (15.02) was observed when Xyl11 was used in association with commercial β-xylosidase. This study provided a novel acidophilic β-xylanase that exhibits excellent characteristics and can, therefore, be considered a suitable candidate for extensive applications, especially in food and animal feed industries.
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Affiliation(s)
- Fengzhen Zheng
- College of Biological and Environmental Engineering, Zhejiang Shuren University, Hangzhou, China
- *Correspondence: Fengzhen Zheng,
| | - Abdul Basit
- Department of Microbiology, University of Jhang, Jhang, Pakistan
| | - Huan Zhuang
- Department of ENT and Head & Neck Surgery, The Children’s Hospital Zhejiang University School of Medicine, Zhejiang, Hangzhou, China
| | - Jun Chen
- Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou, China
| | - Jianfen Zhang
- College of Biological and Environmental Engineering, Zhejiang Shuren University, Hangzhou, China
| | - Weiqing Chen
- College of Biological and Environmental Engineering, Zhejiang Shuren University, Hangzhou, China
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4
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Sanitá Lima M, Coutinho de Lucas R. Co-cultivation, Co-culture, Mixed Culture, and Microbial Consortium of Fungi: An Understudied Strategy for Biomass Conversion. Front Microbiol 2022; 12:837685. [PMID: 35126339 PMCID: PMC8811191 DOI: 10.3389/fmicb.2021.837685] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 12/29/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Matheus Sanitá Lima
- Department of Biology, University of Western Ontario, London, ON, Canada
- *Correspondence: Matheus Sanitá Lima
| | - Rosymar Coutinho de Lucas
- Department of Biology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- Department of Parasitology, Microbiology and Immunology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, Brazil
- Rosymar Coutinho de Lucas
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5
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Neis A, da Silva Pinto L. Glycosyl hydrolases family 5, subfamily 5: Relevance and structural insights for designing improved biomass degrading cocktails. Int J Biol Macromol 2021; 193:980-995. [PMID: 34666133 DOI: 10.1016/j.ijbiomac.2021.10.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
Endoglucanases are carbohydrate-degrading enzymes widely used for bioethanol production as part of the enzymatic cocktail. However, family 5 subfamily 5 (GH5_5) endoglucanases are still poorly explored in depth. The Trichoderma reesei representative is the most studied enzyme, presenting catalytic activity in acidic media and mild temperature conditions. Though biochemically similar, its modular structure and synergy with other components vary greatly compared to other GH5_5 members and there is still a lack of specific studies regarding their interaction with other cellulases and application on novel and better mixtures. In this regard, the threedimensional structure elucidation is a highly valuable tool to both uncover basic catalytic mechanisms and implement engineering techniques, proved by the high success rate GH5_5 endoglucanases show. GH5_5 enzymes must be carefully evaluated to fully uncover their potential in biomass-degrading cocktails: the optimal industrial conditions, synergy with other cellulases, structural studies, and enzyme engineering approaches. We aimed to provide the current understanding of these main topics, collecting all available information about characterized GH5_5 endoglucanases function, structure, and bench experiments, in order to suggest future directions to a better application of these enzymes in the industry.
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Affiliation(s)
- Alessandra Neis
- Laboratório de Bioinformática e Proteômica (BioPro Lab), Centro de Desenvolvimento Tecnológico, Campus Universitário, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Caixa Postal 96010-900, Brazil.
| | - Luciano da Silva Pinto
- Laboratório de Bioinformática e Proteômica (BioPro Lab), Centro de Desenvolvimento Tecnológico, Campus Universitário, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Caixa Postal 96010-900, Brazil.
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6
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Bertacchi S, Jayaprakash P, Morrissey JP, Branduardi P. Interdependence between lignocellulosic biomasses, enzymatic hydrolysis and yeast cell factories in biorefineries. Microb Biotechnol 2021; 15:985-995. [PMID: 34289233 PMCID: PMC8913906 DOI: 10.1111/1751-7915.13886] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/23/2021] [Accepted: 06/23/2021] [Indexed: 11/30/2022] Open
Abstract
Biorefineries have a pivotal role in the bioeconomy scenario for the transition from fossil‐based processes towards more sustainable ones relying on renewable resources. Lignocellulose is a prominent feedstock since its abundance and relatively low cost. Microorganisms are often protagonists of biorefineries, as they contribute both to the enzymatic degradation of lignocellulose complex polymers and to the fermentative conversion of the hydrolyzed biomasses into fine and bulk chemicals. Enzymes have therefore become crucial for the development of sustainable biorefineries, being able to provide nutrients to cells from lignocellulose. Enzymatic hydrolysis can be performed by a portfolio of natural enzymes that degrade lignocellulose, often combined into cocktails. As enzymes can be deployed in different operative settings, such as separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF), their characteristics need to be combined with microbial ones to maximize the process. We therefore reviewed how the optimization of lignocellulose enzymatic hydrolysis can ameliorate bioethanol production when Saccharomyces cerevisiae is used as cell factory. Expanding beyond biofuels, enzymatic cocktail optimization can also be pivotal to unlock the potential of non‐Saccharomyces yeasts, which, thanks to broader substrate utilization, inhibitor resistance and peculiar metabolism, can widen the array of feedstocks and products of biorefineries.
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Affiliation(s)
- Stefano Bertacchi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, Milano, 20126, Italy
| | - Pooja Jayaprakash
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, Milano, 20126, Italy.,School of Microbiology, Environmental Research Institute, APC Microbiome Institute, University College Cork, Cork, T12 K8AF, Ireland
| | - John P Morrissey
- School of Microbiology, Environmental Research Institute, APC Microbiome Institute, University College Cork, Cork, T12 K8AF, Ireland
| | - Paola Branduardi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, Milano, 20126, Italy
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7
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Østby H, Hansen LD, Horn SJ, Eijsink VGH, Várnai A. Enzymatic processing of lignocellulosic biomass: principles, recent advances and perspectives. J Ind Microbiol Biotechnol 2020; 47:623-657. [PMID: 32840713 PMCID: PMC7658087 DOI: 10.1007/s10295-020-02301-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
Efficient saccharification of lignocellulosic biomass requires concerted development of a pretreatment method, an enzyme cocktail and an enzymatic process, all of which are adapted to the feedstock. Recent years have shown great progress in most aspects of the overall process. In particular, increased insights into the contributions of a wide variety of cellulolytic and hemicellulolytic enzymes have improved the enzymatic processing step and brought down costs. Here, we review major pretreatment technologies and different enzyme process setups and present an in-depth discussion of the various enzyme types that are currently in use. We pay ample attention to the role of the recently discovered lytic polysaccharide monooxygenases (LPMOs), which have led to renewed interest in the role of redox enzyme systems in lignocellulose processing. Better understanding of the interplay between the various enzyme types, as they may occur in a commercial enzyme cocktail, is likely key to further process improvements.
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Affiliation(s)
- Heidi Østby
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Line Degn Hansen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway.
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8
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Exploiting strain diversity and rational engineering strategies to enhance recombinant cellulase secretion by Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2020; 104:5163-5184. [PMID: 32337628 DOI: 10.1007/s00253-020-10602-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
Consolidated bioprocessing (CBP) of lignocellulosic material into bioethanol has progressed in the past decades; however, several challenges still exist which impede the industrial application of this technology. Identifying the challenges that exist in all unit operations is crucial and needs to be optimised, but only the barriers related to the secretion of recombinant cellulolytic enzymes in Saccharomyces cerevisiae will be addressed in this review. Fundamental principles surrounding CBP as a biomass conversion platform have been established through the successful expression of core cellulolytic enzymes, namely β-glucosidases, endoglucanases, and exoglucanases (cellobiohydrolases) in S. cerevisiae. This review will briefly address the challenges involved in the construction of an efficient cellulolytic yeast, with particular focus on the secretion efficiency of cellulases from this host. Additionally, strategies for studying enhanced cellulolytic enzyme secretion, which include both rational and reverse engineering approaches, will be discussed. One such technique includes bio-engineering within genetically diverse strains, combining the strengths of both natural strain diversity and rational strain development. Furthermore, with the advancement in next-generation sequencing, studies that utilise this method of exploiting intra-strain diversity for industrially relevant traits will be reviewed. Finally, future prospects are discussed for the creation of ideal CBP strains with high enzyme production levels.Key Points• Several challenges are involved in the construction of efficient cellulolytic yeast, in particular, the secretion efficiency of cellulases from the hosts.• Strategies for enhancing cellulolytic enzyme secretion, a core requirement for CBP host microorganism development, include both rational and reverse engineering approaches.• One such technique includes bio-engineering within genetically diverse strains, combining the strengths of both natural strain diversity and rational strain development.
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9
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Zhang R. Functional characterization of cellulose-degrading AA9 lytic polysaccharide monooxygenases and their potential exploitation. Appl Microbiol Biotechnol 2020; 104:3229-3243. [PMID: 32076777 DOI: 10.1007/s00253-020-10467-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 12/25/2019] [Accepted: 02/12/2020] [Indexed: 01/05/2023]
Abstract
Cellulose-degrading auxiliary activity family 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) are known to be widely distributed among filamentous fungi and participate in the degradation of lignocellulose via the oxidative cleavage of celluloses, cello-oligosaccharides, or hemicelluloses. AA9 LPMOs have been reported to have extensive interactions with not only cellulases but also oxidases. The addition of AA9 LPMOs can greatly reduce the amount of cellulase needed for saccharification and increase the yield of glucose. The discovery of AA9 LPMOs has greatly changed our understanding of how fungi degrade cellulose. In this review, apart from summarizing the recent discoveries related to their catalytic reaction, functional diversity, and practical applications, the stability, expression system, and protein engineering of AA9 LPMOs are reviewed for the first time. This review may provide a reference value to further broaden the substrate range of AA9 LPMOs, expand the scope of their practical applications, and realize their customization for industrial utilization.Key Points• The stability and expression system of AA9 LPMOs are reviewed for the first time.• The protein engineering of AA9 LPMOs is systematically summarized for the first time.• The latest research results on the catalytic mechanism of AA9 LPMOs are summarized.• The application of AA9 LPMOs and their relationship with other enzymes are reviewed.
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Affiliation(s)
- Ruiqin Zhang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
- Department of Bioengineering, Huainan Normal University, No. 278 Xueyuannan Road, Huainan, 232038, China.
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10
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Yilmaz-Sercinoglu Z, Sayar NA. Process simulation-integrated optimization of lignocellulolytic enzyme production. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2019.107420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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Yuan Z, Singh SK, Bals B, Hodge DB, Hegg EL. Integrated Two-Stage Alkaline–Oxidative Pretreatment of Hybrid Poplar. Part 2: Impact of Cu-Catalyzed Alkaline Hydrogen Peroxide Pretreatment Conditions on Process Performance and Economics. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00901] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Zhaoyang Yuan
- Department of Biochemistry & Molecular Biology, Michigan State University, 603 Wilson Road, East Lansing, Michigan 48824, United States
| | - Sandip Kumar Singh
- Department of Chemical & Biological Engineering, Montana State University, 306 Cobleigh Hall, Bozeman, Montana 59717, United States
| | - Bryan Bals
- Michigan Biotechnology Institute, 3815 Technology Boulevard, Lansing, Michigan 48910, United States
| | - David B. Hodge
- Department of Chemical & Biological Engineering, Montana State University, 306 Cobleigh Hall, Bozeman, Montana 59717, United States
- Division of Sustainable Process Engineering, Luleå University of Technology, 97187 Luleå, Sweden
| | - Eric L. Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, 603 Wilson Road, East Lansing, Michigan 48824, United States
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12
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Karnaouri A, Antonopoulou I, Zerva A, Dimarogona M, Topakas E, Rova U, Christakopoulos P. Thermophilic enzyme systems for efficient conversion of lignocellulose to valuable products: Structural insights and future perspectives for esterases and oxidative catalysts. BIORESOURCE TECHNOLOGY 2019; 279:362-372. [PMID: 30685134 DOI: 10.1016/j.biortech.2019.01.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/12/2019] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
Thermophilic enzyme systems are of major importance nowadays in all industrial processes due to their great performance at elevated temperatures. In the present review, an overview of the current knowledge on the properties of thermophilic and thermotolerant carbohydrate esterases and oxidative enzymes with great thermostability is provided, with respect to their potential use in biotechnological applications. A special focus is given to the lytic polysaccharide monooxygenases that are able to oxidatively cleave lignocellulose through the use of oxygen or hydrogen peroxide as co-substrate and a reducing agent as electron donor. Structural characteristics of the enzymes, including active site conformation and surface properties are discussed and correlated with their substrate specificity and thermostability properties.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
| | - Io Antonopoulou
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Anastasia Zerva
- Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Maria Dimarogona
- Section of Process and Environmental Engineering, Department of Chemical Engineering, University of Patras, 26504 Rio, Patras, Greece
| | - Evangelos Topakas
- Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
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13
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Zhang F, Bunterngsook B, Li JX, Zhao XQ, Champreda V, Liu CG, Bai FW. Regulation and production of lignocellulolytic enzymes from Trichoderma reesei for biofuels production. ADVANCES IN BIOENERGY 2019. [DOI: 10.1016/bs.aibe.2019.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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Zhao T, Tashiro Y, Zheng J, Sakai K, Sonomoto K. Semi-hydrolysis with low enzyme loading leads to highly effective butanol fermentation. BIORESOURCE TECHNOLOGY 2018; 264:335-342. [PMID: 29886308 DOI: 10.1016/j.biortech.2018.05.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/14/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
To improve butanol fermentation efficiencies, semi-hydrolysate with low enzyme loading using H2SO4 pretreated rice straw was designed, which preferably produced cellobiose with xylose (instead of glucose). Fermentation of semi-hydrolysates avoided carbon catabolite repression (CCR) and produced higher butanol yield to enzyme loading (0.0290 g U-1), a newly proposed parameter, than the conventional glucose-oriented hydrolysate (0.00197 g U-1). Further, overall butanol productivity was improved from 0.0628 g L-1 h-1 to 0.265 g L-1 h-1 during fermentation of undetoxified semi-hydrolysate by using high cell density. A novel simultaneously repeated hydrolysis and fermentation (SRHF) was constructed by recycling of enzymes and cells, which further improved butanol yield to enzyme loading by 183% and overall butanol productivity by 6.04%. Thus, semi-hydrolysate with SRHF is a smartly designed biomass for efficient butanol fermentation of lignocellulosic materials.
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Affiliation(s)
- Tao Zhao
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Yukihiro Tashiro
- Laboratory of Soil and Environmental Microbiology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan; Laboratory of Microbial Environmental Protection, Tropical Microbiology Unit, Center for International Education and Research of Agriculture, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Jin Zheng
- State Key Lab of Petroleum Pollution Control, Beijing 102206, China; Research Division of Environment Technology, CNPC Research Institute of Safety & Environmental Technology, Beijing 102206, China
| | - Kenji Sakai
- Laboratory of Soil and Environmental Microbiology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan; Laboratory of Microbial Environmental Protection, Tropical Microbiology Unit, Center for International Education and Research of Agriculture, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Kenji Sonomoto
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
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15
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Conway JM, Crosby JR, McKinley BS, Seals NL, Adams MWW, Kelly RM. Parsing in vivo and in vitro contributions to microcrystalline cellulose hydrolysis by multidomain glycoside hydrolases in theCaldicellulosiruptor besciisecretome. Biotechnol Bioeng 2018; 115:2426-2440. [DOI: 10.1002/bit.26773] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 05/21/2018] [Accepted: 06/21/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Jonathan M. Conway
- Department of Chemical and Biomolecular EngineeringNorth Carolina State UniversityRaleigh NC
| | - James R. Crosby
- Department of Chemical and Biomolecular EngineeringNorth Carolina State UniversityRaleigh NC
| | - Bennett S. McKinley
- Department of Chemical and Biomolecular EngineeringNorth Carolina State UniversityRaleigh NC
| | - Nathaniel L. Seals
- Department of Chemical and Biomolecular EngineeringNorth Carolina State UniversityRaleigh NC
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular BiologyUniversity of GeorgiaAthens GA
| | - Robert M. Kelly
- Department of Chemical and Biomolecular EngineeringNorth Carolina State UniversityRaleigh NC
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16
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Monrad RN, Eklöf J, Krogh KBRM, Biely P. Glucuronoyl esterases: diversity, properties and biotechnological potential. A review. Crit Rev Biotechnol 2018; 38:1121-1136. [PMID: 29739247 DOI: 10.1080/07388551.2018.1468316] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Glucuronoyl esterases (GEs) belonging to the carbohydrate esterase family 15 (CE15) are involved in microbial degradation of lignocellulosic plant materials. GEs are capable of degrading complex polymers of lignin and hemicellulose cleaving ester bonds between glucuronic acid residues in xylan and lignin alcohols. GEs promote separation of lignin, hemicellulose and cellulose which is crucial for efficient utilization of biomass as an energy source and feedstock for further processing into products or chemicals. Genes encoding GEs are found in both fungi and bacteria, but, so far, bacterial GEs are essentially unexplored, and despite being discovered >10 years ago, only a limited number of GEs have been characterized. The first laboratory scale example of improved xylose and glucuronic acid release by the synergistic action of GE with cellulolytic enzymes was only reported recently (improved C5 sugar and glucuronic acid yields) and, until now, not much is known about their biotechnology potential. In this review, we discuss the diversity, structure and properties of microbial GEs and consider the status of their action on natural substrates and in biological systems in relation to their future industrial use.
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Affiliation(s)
| | | | | | - Peter Biely
- b Institute of Chemistry, Slovak Academy of Sciences , Bratislava , Slovak Republic
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de Assis T, Huang S, Driemeier CE, Donohoe BS, Kim C, Kim SH, Gonzalez R, Jameel H, Park S. Toward an understanding of the increase in enzymatic hydrolysis by mechanical refining. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:289. [PMID: 30386426 PMCID: PMC6201573 DOI: 10.1186/s13068-018-1289-3] [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: 08/14/2018] [Accepted: 10/09/2018] [Indexed: 05/11/2023]
Abstract
BACKGROUND Mechanical refining is a low-capital and well-established technology used in pulp and paper industry to improve fiber bonding for product strength. Refining can also be applied in a biorefinery context to overcome the recalcitrance of pretreated biomass by opening up the biomass structure and modifying substrate properties (e.g., morphology, particle size, porosity, crystallinity), which increases enzyme accessibility to substrate and improves carbohydrate conversion. Although several characterization methods have been used to identify the changes in substrate properties, there is no systematic approach to evaluate the extent of fiber cell wall disruption and what physical properties can explain the improvement in enzymatic digestibility when pretreated lignocellulosic biomass is mechanically refined. This is because the fiber cell wall is complex across multiple scales, including the molecular scale, nano- and meso-scale (microfibril), and microscale (tissue level). A combination of advanced characterization tools is used in this study to better understand the effect of mechanical refining on the meso-scale microfibril assembly and the relationship between those meso-scale modifications and enzymatic hydrolysis. RESULTS Enzymatic conversion of autohydrolysis sugarcane bagasse was improved from 69.6 to 77.2% (11% relative increase) after applying mechanical refining and an increase in enzymatic digestibility is observed with an increase in refining intensity. Based on a combination of advanced characterizations employed in this study, it was found that the refining action caused fiber size reduction, internal delamination, and increase in pores and swellability. CONCLUSIONS A higher level of delamination and higher increase in porosity, analyzed by TEM and DSC, were clearly demonstrated, which explain the faster digestibility rate during the first 72 h of enzymatic hydrolysis for disc-refined samples when compared to the PFI-refined samples. In addition, an increased inter-fibrillar distance between cellulose microfibrils at the nano-meso-scale was also revealed by SFG analysis, while no evidence was found for a change in crystalline structure by XRD and solid-state NMR analysis.
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Affiliation(s)
- Tiago de Assis
- Department of Forest Biomaterials, College of Natural Reseources, NC State University, Raleigh, NC USA
| | - Shixin Huang
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA USA
| | - Carlos Eduardo Driemeier
- Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP Brazil
| | - Bryon S. Donohoe
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Chaehoon Kim
- Department of Forest Biomaterials, College of Natural Reseources, NC State University, Raleigh, NC USA
| | - Seong H. Kim
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA USA
| | - Ronalds Gonzalez
- Department of Forest Biomaterials, College of Natural Reseources, NC State University, Raleigh, NC USA
| | - Hasan Jameel
- Department of Forest Biomaterials, College of Natural Reseources, NC State University, Raleigh, NC USA
| | - Sunkyu Park
- Department of Forest Biomaterials, College of Natural Reseources, NC State University, Raleigh, NC USA
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18
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You S, Chen CC, Tu T, Wang X, Ma R, Cai HY, Guo RT, Luo HY, Yao B. Insight into the functional roles of Glu175 in the hyperthermostable xylanase XYL10C-ΔN through structural analysis and site-saturation mutagenesis. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:159. [PMID: 29930705 PMCID: PMC5992652 DOI: 10.1186/s13068-018-1150-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/23/2018] [Indexed: 05/16/2023]
Abstract
BACKGROUND Improving the hydrolytic performance of hemicellulases to degrade lignocellulosic biomass is of considerable importance for second-generation biorefinery. Xylanase, as the crucial hemicellulase, must be thermostable and have high activity for its potential use in the bioethanol industry. To obtain excellent xylanase candidates, it is necessary to understand the structure-function relationships to provide a meaningful reference to improve the enzyme properties. This study aimed to investigate the catalytic mechanism of a highly active hyperthermophilic xylanase variant, XYL10C-ΔN, for hemicellulose degradation. RESULTS By removing the N-terminal 66 amino acids, the variant XYL10C-ΔN showed a 1.8-fold improvement in catalytic efficiency and could hydrolyze corn stover more efficiently in hydrolysis of corn stover; however, it retained similar thermostability to the wild-type XYL10C. Based on the crystal structures of XYL10C-ΔN and its complex with xylobiose, Glu175 located on loop 3 was found to be specific to GH10 xylanases and probably accounts for the excellent enzyme properties by interacting with Lys135 and Met137 on loop 2. Site-saturation mutagenesis confirmed that XYL10C-ΔN with glutamate acid at position 175 had the highest catalytic efficiency, specific activity, and the broadest pH-activity profile. The functional roles of Glu175 were also verified in the mutants of another two GH10 xylanases, XylE and XynE2, which showed increased catalytic efficiencies and wider pH-activity profiles. CONCLUSIONS XYL10C-ΔN, with excellent thermostability, high catalytic efficiency, and great lignocellulose-degrading capability, is a valuable candidate xylanase for the biofuel industry. The mechanism underlying improved activity of XYN10C-ΔN was thus investigated through structural analysis and functional verification, and Glu175 was identified to play the key role in the improved catalytic efficiency. This study revealed the importance of a key residue (Glu175) in XYN10C-ΔN and provides a reference to modify GH10 xylanases for improved catalytic performance.
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Affiliation(s)
- Shuai You
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Chun-Chi Chen
- National Engineering Laboratory of Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- College of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Tao Tu
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Xiaoyu Wang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Rui Ma
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Hui-yi Cai
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Rey-Ting Guo
- National Engineering Laboratory of Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- College of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Hui-ying Luo
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Bin Yao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
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19
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Kumar D, Murthy GS. Development and validation of a stochastic molecular model of cellulose hydrolysis by action of multiple cellulase enzymes. BIORESOUR BIOPROCESS 2017. [DOI: 10.1186/s40643-017-0184-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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20
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Qian Y, Zhong L, Gao J, Sun N, Wang Y, Sun G, Qu Y, Zhong Y. Production of highly efficient cellulase mixtures by genetically exploiting the potentials of Trichoderma reesei endogenous cellulases for hydrolysis of corncob residues. Microb Cell Fact 2017; 16:207. [PMID: 29162107 PMCID: PMC5696804 DOI: 10.1186/s12934-017-0825-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/14/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trichoderma reesei is one of the most important fungi utilized for cellulase production. However, its cellulase system has been proven to be present in suboptimal ratio for deconstruction of lignocellulosic substrates. Although previous enzymatic optimization studies have acquired different types of in vitro synthetic mixtures for efficient lignocellulose hydrolysis, production of in vivo optimized cellulase mixtures by industrial strains remains one of the obstacles to reduce enzyme cost in the biofuels production from lignocellulosic biomass. RESULTS In this study, we used a systematic genetic strategy based on the pyrG marker to overexpress the major cellulase components in a hypercellulolytic T. reesei strain and produce the highly efficient cellulase mixture for saccharification of corncob residues. We found that overexpression of CBH2 exhibited a 32-fold increase in the transcription level and a comparable protein level to CBH1, the most abundant secreted protein in T. reesei, but did not contribute much to the cellulolytic ability. However, when EG2 was overexpressed with a 46-fold increase in the transcription level and a comparable protein level to CBH2, the engineered strain QPE36 showed a 1.5-fold enhancement in the total cellulase activity (up to 5.8 U/mL FPA) and a significant promotion of saccharification efficiency towards differently pretreated corncob residues. To assist the following genetic manipulations, the marker pyrG was successfully excised by homologous recombination based on resistance to 5-FOA. Furthermore, BGL1 was overexpressed in the EG2 overexpression strain QE51 (pyrG-excised) and a 11.6-fold increase in BGL activity was obtained. The EG2-BGL1 double overexpression strain QEB4 displayed a remarkable enhancement of cellulolytic ability on pretreated corncob residues. Especially, a nearly complete cellulose conversion (94.2%) was found for the delignified corncob residues after 48 h enzymatic saccharification. CONCLUSIONS These results demonstrate that genetically exploiting the potentials of T. reesei endogenous cellulases to produce highly efficient cellulase mixtures is a powerful strategy to promote the saccharification efficiency, which will eventually facilitate cost reduction for lignocellulose-based biofuels.
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Affiliation(s)
- Yuanchao Qian
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Lixia Zhong
- Shandong Institute for Food and Drug Control, Jinan, 250101, People's Republic of China
| | - Jia Gao
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Ningning Sun
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Yifan Wang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Guoyong Sun
- Anaesthesiology Department of the Second Hospital of Shandong University, Jinan, 250100, People's Republic of China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China.
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Mir BA, Myburg AA, Mizrachi E, Cowan DA. In planta expression of hyperthermophilic enzymes as a strategy for accelerated lignocellulosic digestion. Sci Rep 2017; 7:11462. [PMID: 28904370 PMCID: PMC5597601 DOI: 10.1038/s41598-017-11026-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 06/14/2017] [Indexed: 11/24/2022] Open
Abstract
Conversion of lignocellulosic biomass to biofuels and biomaterials suffers from high production costs associated with biomass pretreatment and enzymatic hydrolysis. In-planta expression of lignocellulose-digesting enzymes is a promising approach to reduce these cost elements. However, this approach faces a number of challenges, including auto-hydrolysis of developing cell walls, plant growth and yield penalties, low expression levels and the limited stability of expressed enzymes at the high temperatures generally used for biomass processing to release fermentable sugars. To overcome these challenges we expressed codon-optimized recombinant hyperthermophilic endoglucanase (EG) and xylanase (Xyn) genes in A. thaliana. Transgenic Arabidopsis lines expressing EG and Xyn enzymes at high levels without any obvious plant growth or yield penalties were selected for further analysis. The highest enzyme activities were observed in the dry stems of transgenic lines, indicating that the enzymes were not degraded during stem senescence and storage. Biomass from transgenic lines exhibited improved saccharification efficiency relative to WT control plants. We conclude that the expression of hyperthermophilic enzymes in plants is a promising approach for combining pretreatment and enzymatic hydrolysis processes in lignocellulosic digestion. This study provides a valid foundation for further studies involving in planta co-expression of core and accessory lignocellulose-digesting enzymes.
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Affiliation(s)
- Bilal Ahmad Mir
- Centre for Microbial Ecology and Genomics, Department of Genetics, University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa.,Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa.,Department of Botany, School of Life Sciences, Satellite Campus Kargil, University of Kashmir, Jammu & Kashmir, India
| | - Alexander A Myburg
- Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Eshchar Mizrachi
- Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Genetics, University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa.
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22
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Menegol D, Scholl AL, Dillon AJP, Camassola M. Use of elephant grass (Pennisetum purpureum) as substrate for cellulase and xylanase production in solid-state cultivation by Penicillium echinulatum. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2017. [DOI: 10.1590/0104-6632.20170343s20150822] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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23
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Wu H, Li H, Xue Y, Luo G, Gan L, Liu J, Mao L, Long M. High efficiency co-production of ferulic acid and xylooligosaccharides from wheat bran by recombinant xylanase and feruloyl esterase. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.01.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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24
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Chylenski P, Forsberg Z, Ståhlberg J, Várnai A, Lersch M, Bengtsson O, Sæbø S, Horn SJ, Eijsink VGH. Development of minimal enzyme cocktails for hydrolysis of sulfite-pulped lignocellulosic biomass. J Biotechnol 2017; 246:16-23. [PMID: 28219736 DOI: 10.1016/j.jbiotec.2017.02.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 01/02/2023]
Abstract
Despite recent progress, saccharification of lignocellulosic biomass is still a major cost driver in biorefining. In this study, we present the development of minimal enzyme cocktails for hydrolysis of Norway spruce and sugarcane bagasse, which were pretreated using the so-called BALI™ process, which is based on sulfite pulping technology. Minimal enzyme cocktails were composed using several glycoside hydrolases purified from the industrially relevant filamentous fungus Trichoderma reesei and a purified commercial β-glucosidase from Aspergillus niger. The contribution of in-house expressed lytic polysaccharide monooxygenases (LPMOs) was also tested, since oxidative cleavage of cellulose by such LPMOs is known to be beneficial for conversion efficiency. We show that the optimized cocktails permit efficient saccharification at reasonable enzyme loadings and that the effect of the LPMOs is substrate-dependent. Using a cocktail comprising only four enzymes, glucan conversion for Norway spruce reached >80% at enzyme loadings of 8mg/g glucan, whereas almost 100% conversion was achieved at 16mg/g.
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Affiliation(s)
- Piotr Chylenski
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Zarah Forsberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anikó Várnai
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | | | | | - Solve Sæbø
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Svein Jarle Horn
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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Functional diversity for biomass deconstruction in family 5 subfamily 5 (GH5_5) of fungal endo-β1,4-glucanases. Appl Microbiol Biotechnol 2017; 101:4093-4101. [PMID: 28197688 DOI: 10.1007/s00253-017-8168-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 12/21/2022]
Abstract
Endo-β1,4-glucanases in glycosyl hydrolase family 5 (GH5) are ubiquitous enzymes in the multicellular fungi and are common components of enzyme cocktails for biomass conversion. We recently showed that an endo-glucanase of subfamily 5 of GH5 (GH5_5) from Sporotrichum thermophile (StCel5A) was more effective at releasing glucose from pretreated corn stover, when part of an eight-component synthetic enzyme mixture, compared to its closely related counterpart from Trichoderma reesei, TrCel5A. StCel5A and TrCel5A belong to different clades of GH5_5 (GH5_5_1 and GH5_5_2, respectively). To test whether the superior activity of StCel5A was a general property of all enzymes in the GH5_5_2 clade, StCel5A, TrCel5A, and two additional members of each subfamily were expressed in a common host that had been engineered to suppress its native cellulases (T. reesei Δxyr1) and compared against each other alone on pure substrates, in synthetic mixtures on pure substrates, and against each other in synthetic mixtures on real biomass. The results indicated that superiority is a unique property of StCel5A and not of GH5_5_2 generally. The six Cel5A enzymes had significant differences in relative activities on different substrates, in specific activities, and in sensitivities to mannan inhibition. Importantly, the behavior of the six endo-glucanases on pure cellulose substrates did not predict their behavior in combination with other cellulolytic enzymes on a real lignocellulosic biomass substrate.
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26
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Ventorino V, Ionata E, Birolo L, Montella S, Marcolongo L, de Chiaro A, Espresso F, Faraco V, Pepe O. Lignocellulose-Adapted Endo-Cellulase Producing Streptomyces Strains for Bioconversion of Cellulose-Based Materials. Front Microbiol 2016; 7:2061. [PMID: 28066379 PMCID: PMC5177626 DOI: 10.3389/fmicb.2016.02061] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 12/07/2016] [Indexed: 11/13/2022] Open
Abstract
Twenty-four Actinobacteria strains, isolated from Arundo donax, Eucalyptus camaldulensis and Populus nigra biomass during natural biodegradation and with potential enzymatic activities specific for the degradation of lignocellulosic materials, were identified by a polyphasic approach. All strains belonged to the genus Streptomyces (S.) and in particular, the most highly represented species was Streptomyces argenteolus representing 50% of strains, while 8 strains were identified as Streptomyces flavogriseus (synonym S. flavovirens) and Streptomyces fimicarius (synonyms Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies, and Streptomyces flavofuscus), and the other four strains belonged to the species Streptomyces drozdowiczii, Streptomyces rubrogriseus, Streptomyces albolongus, and Streptomyces ambofaciens. Moreover, all Streptomyces strains, tested for endo and exo-cellulase, cellobiase, xylanase, pectinase, ligninase, peroxidase, and laccase activities using qualitative and semi-quantitative methods on solid growth medium, exhibited multiple enzymatic activities (from three to six). The 24 strains were further screened for endo-cellulase activity in liquid growth medium and the four best endo-cellulase producers (S. argenteolus AE58P, S. argenteolus AE710A, S. argenteolus AE82P, and S. argenteolus AP51A) were subjected to partial characterization and their enzymatic crude extracts adopted to perform saccharification experiments on A. donax pretreated biomass. The degree of cellulose and xylan hydrolysis was evaluated by determining the kinetics of glucose and xylose release during 72 h incubation at 50°C from the pretreated biomass in the presence of cellulose degrading enzymes (cellulase and β-glucosidase) and xylan related activities (xylanase and β-xylosidase). The experiments were carried out utilizing the endo-cellulase activities from the selected S. argenteolus strains supplemented with commercial β-gucosidase and xylanase preparations from Genencore (Accellerase BG and Accellerase XY). Cellulose and xylan conversion, when conducted using commercial (hemi)cellulases, gave glucose and xylose yields of 30.17 and 68.9%, respectively. The replacement of the cellulolytic preparation from Genencor (Accellerase 1500), with the endo-cellulase from S. argenteolus AE58P resulted in almost 76% of the glucose yield obtained in the presence of the commercial counterpart. Due to the promising results obtained by using the enzymatic crude extracts from S. argenteolus AE58P in the pretreated A. donax saccharification experiments, the proteins putatively responsible for endo-cellulase activity in this strain were identified by proteomics. Several proteins were confidently identified in different Streptomyces spp., eight of which belong to the class of Carbohydrate active enzymes. Overall results highlighted the biotechnological potential of S. argenteolus AE58P being an interesting candidate biocatalyst-producing bacterium for lignocellulose conversion and production of biochemicals and bioenergy.
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Affiliation(s)
- Valeria Ventorino
- Department of Agricultural Sciences, University of Naples Federico IINaples, Italy
| | - Elena Ionata
- Institute of Biosciences and BioResources—National Research CouncilNaples, Italy
| | - Leila Birolo
- Department of Chemical Sciences, University of Naples Federico IINaples, Italy
| | - Salvatore Montella
- Department of Chemical Sciences, University of Naples Federico IINaples, Italy
| | - Loredana Marcolongo
- Institute of Biosciences and BioResources—National Research CouncilNaples, Italy
| | - Addolorata de Chiaro
- Institute of Biosciences and BioResources—National Research CouncilNaples, Italy
| | - Francesco Espresso
- Department of Agricultural Sciences, University of Naples Federico IINaples, Italy
| | - Vincenza Faraco
- Department of Chemical Sciences, University of Naples Federico IINaples, Italy
| | - Olimpia Pepe
- Department of Agricultural Sciences, University of Naples Federico IINaples, Italy
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27
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Morrison JM, Elshahed MS, Youssef NH. Defined enzyme cocktail from the anaerobic fungus Orpinomyces sp. strain C1A effectively releases sugars from pretreated corn stover and switchgrass. Sci Rep 2016; 6:29217. [PMID: 27381262 PMCID: PMC4933900 DOI: 10.1038/srep29217] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/13/2016] [Indexed: 02/08/2023] Open
Abstract
The anaerobic fungus Orpinomyces strain C1A is capable of growth on various types of lignocellulosic substrates, and harbors an impressive reservoir of carbohydrate active enzymes (CAZymes). Using a minimum enzyme cocktail strategy, we constituted a four-component lignocellulolytic cocktail derived from highly transcribed C1A, and evaluated its efficacy against pretreated corn stover and switchgrass. Hydrolysis yields ranged between 65–77.4%, depending on the lignocellulosic substrate and pretreatment applied. Addition of a highly expressed anaerobic fungal swollenin improved hydrolysis yields by up to 7%. Compared to the commercial cocktail CTec2, these anaerobic fungal cocktails provided comparable or slightly lower hydrolysis yields. Further, the differences in efficacy between commercial and anaerobic cocktails were often only realized after extended (168 hr) incubations. Under certain conditions, the hydrolysis yields of the anaerobic fungal cocktail was slightly superior to that realized by CTec2. We attribute the observed high hydrolysis yields to the high specific activity and affinity of the individual enzymes of the cocktail, as well as the high level of synergy and multi-functionality observed in multiple components. Collectively, this effort provides a novel platform for constructing highly effective enzymes for biofuel production and represents the first lignocellulolytic enzyme cocktail created from anaerobic fungal enzymes.
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Affiliation(s)
- Jessica M Morrison
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Mostafa S Elshahed
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Noha H Youssef
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
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28
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Co-Cultivation of Penicillium sp. AKB-24 and Aspergillus nidulans AKB-25 as a Cost-Effective Method to Produce Cellulases for the Hydrolysis of Pearl Millet Stover. FERMENTATION-BASEL 2016. [DOI: 10.3390/fermentation2020012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Attia M, Stepper J, Davies GJ, Brumer H. Functional and structural characterization of a potent GH74 endo-xyloglucanase from the soil saprophyte Cellvibrio japonicus unravels the first step of xyloglucan degradation. FEBS J 2016; 283:1701-19. [PMID: 26929175 DOI: 10.1111/febs.13696] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/09/2016] [Accepted: 02/25/2016] [Indexed: 11/27/2022]
Abstract
UNLABELLED The heteropolysaccharide xyloglucan (XyG) comprises up to one-quarter of the total carbohydrate content of terrestrial plant cell walls and, as such, represents a significant reservoir in the global carbon cycle. The complex composition of XyG requires a consortium of backbone-cleaving endo-xyloglucanases and side-chain cleaving exo-glycosidases for complete saccharification. The biochemical basis for XyG utilization by the model Gram-negative soil saprophytic bacterium Cellvibrio japonicus is incompletely understood, despite the recent characterization of associated side-chain cleaving exo-glycosidases. We present a detailed functional and structural characterization of a multimodular enzyme encoded by gene locus CJA_2477. The CJA_2477 gene product comprises an N-terminal glycoside hydrolase family 74 (GH74) endo-xyloglucanase module in train with two carbohydrate-binding modules (CBMs) from families 10 and 2 (CBM10 and CBM2). The GH74 catalytic domain generates Glc4 -based xylogluco-oligosaccharide (XyGO) substrates for downstream enzymes through an endo-dissociative mode of action. X-ray crystallography of the GH74 module, alone and in complex with XyGO products spanning the entire active site, revealed a broad substrate-binding cleft specifically adapted to XyG recognition, which is composed of two seven-bladed propeller domains characteristic of the GH74 family. The appended CBM10 and CBM2 members notably did not bind XyG, nor other soluble polysaccharides, and instead were specific cellulose-binding modules. Taken together, these data shed light on the first step of xyloglucan utilization by C. japonicus and expand the repertoire of GHs and CBMs for selective biomass analysis and utilization. DATABASE Structural data have been deposited in the RCSB protein database under the Protein Data Bank codes: 5FKR, 5FKS, 5FKT and 5FKQ.
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Affiliation(s)
- Mohamed Attia
- Michael Smith Laboratories and Department of Chemistry, University of British Columbia, Vancouver, Canada
| | | | | | - Harry Brumer
- Michael Smith Laboratories and Department of Chemistry, University of British Columbia, Vancouver, Canada
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Karnaouri A, Matsakas L, Topakas E, Rova U, Christakopoulos P. Development of Thermophilic Tailor-Made Enzyme Mixtures for the Bioconversion of Agricultural and Forest Residues. Front Microbiol 2016; 7:177. [PMID: 26909078 PMCID: PMC4754399 DOI: 10.3389/fmicb.2016.00177] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/01/2016] [Indexed: 11/13/2022] Open
Abstract
Even though the main components of all lignocellulosic feedstocks include cellulose, hemicellulose, as well as the protective lignin matrix, there are some differences in structure, such as in hardwoods and softwoods, which may influence the degradability of the materials. Under this view, various types of biomass might require a minimal set of enzymes that has to be tailor-made. Partially defined complex mixtures that are currently commercially used are not adapted to efficiently degrade different materials, so novel enzyme mixtures have to be customized. Development of these cocktails requires better knowledge about the specific activities involved, in order to optimize hydrolysis. The role of filamentous fungus Myceliophthora thermophila and its complete enzymatic repertoire for the bioconversion of complex carbohydrates has been widely proven. In this study, four core cellulases (MtCBH7, MtCBH6, MtEG5, and MtEG7), in the presence of other four "accessory" enzymes (mannanase, lytic polyssacharide monooxygenase MtGH61, xylanase, MtFae1a) and β-glucosidase MtBGL3, were tested as a nine-component cocktail against one model substrate (phosphoric acid swollen cellulose) and four hydrothermally pretreated natural substrates (wheat straw as an agricultural waste, birch, and spruce biomass, as forest residues). Synergistic interactions among different enzymes were determined using a suitable design of experiments methodology. The results suggest that for the hydrolysis of the pure substrate (PASC), high proportions of MtEG7 are needed for efficient yields. MtCBH7 and MtEG7 are enzymes of major importance during the hydrolysis of pretreated wheat straw, while MtCBH7 plays a crucial role in case of spruce. Cellobiohydrolases MtCBH6 and MtCBH7 act in combination and are key enzymes for the hydrolysis of the hardwood (birch). Optimum combinations were predicted from suitable statistical models which were able to further increase hydrolysis yields, suggesting that tailor-made enzyme mixtures targeted toward a particular residual biomass can help maximize hydrolysis yields. The present work demonstrates the change from "one cocktail for all" to "tailor-made cocktails" that are needed for the efficient saccharification of targeted feed stocks prior to the production of biobased products through the biorefinery concept.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
| | - Leonidas Matsakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
| | - Evangelos Topakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of TechnologyLuleå, Sweden; Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of AthensAthens, Greece
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
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de Lima EA, Machado CB, Zanphorlin LM, Ward RJ, Sato HH, Ruller R. GH53 Endo-Beta-1,4-Galactanase from a Newly Isolated Bacillus licheniformis CBMAI 1609 as an Enzymatic Cocktail Supplement for Biomass Saccharification. Appl Biochem Biotechnol 2016; 179:415-26. [DOI: 10.1007/s12010-016-2003-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/27/2016] [Indexed: 11/24/2022]
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Song W, Han X, Qian Y, Liu G, Yao G, Zhong Y, Qu Y. Proteomic analysis of the biomass hydrolytic potentials of Penicillium oxalicum lignocellulolytic enzyme system. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:68. [PMID: 26997974 PMCID: PMC4797192 DOI: 10.1186/s13068-016-0477-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/02/2016] [Indexed: 05/08/2023]
Abstract
BACKGROUND The mining of high-performance enzyme systems is necessary to develop industrial lignocellulose bioconversion. Large amounts of cellulases and hemicellulases can be produced by Penicillium oxalicum. Hence, the enzyme system of this hypercellulolytic fungus should be elucidated to help design optimum enzyme systems for effective biomass hydrolysis. RESULTS The cellulolytic and xylanolytic activities of an SP enzyme system prepared from P. oxalicum JU-A10 were comparatively analyzed. Results indicated that the fungus possesses a complete cellulolytic-xylanolytic enzyme system. The cellobiohydrolase- and xylanase-specific activities of this system were higher than those of two other enzyme systems, i.e., ST from Trichoderma reesei SN1 and another commercial preparation Celluclast 1.5L. Delignified corncob residue (DCCR) could be hydrolyzed by SP to a greater extent than corncob residue (CCR). Beta-glucosidase (BG) supplemented in SP increased the ability of the system to hydrolyze DCCR and CCR, and resulted in a 64 % decrease in enzyme dosage with the same glucose yield. The behaviors of the enzyme components in the hydrolysis of CCR were further investigated by monitoring individual enzyme dynamics. The total protein concentrations and cellobiohydrolase (CBH), endoglucanase (EG), and filter paper activities in the supernatants significantly decreased during saccharification. These findings were more evident in SP than in the other enzyme systems. The comparative proteomic analysis of the enzyme systems revealed that both SP and ST were rich in carbohydrate-degrading enzymes and multiple non-hydrolytic proteins. A larger number of carbohydrate-binding modules 1 (CBM1) were also identified in SP than in ST. This difference might be linked to the greater adsorption to substrates and lower hydrolysis efficiency of SP enzymes than ST during lignocellulose saccharification, because CBM1 not only targets enzymes to insoluble cellulose but also leads to non-productive adsorption to lignin. CONCLUSIONS Penicillium oxalicum can be applied to the biorefinery of lignocellulosic biomass. Its ability to degrade lignocellulosic substrates could be further improved by modifying its enzyme system on the basis of enzyme activity measurement and proteomic analysis. The proposed strategy may also be applied to other lignocellulolytic enzyme systems to enhance their hydrolytic performances rationally.
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Affiliation(s)
- Wenxia Song
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Xiaolong Han
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Yuanchao Qian
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Guodong Liu
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Guangshan Yao
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Yaohua Zhong
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Yinbo Qu
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
- />National Glycoengineering Research Center, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
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Liguori R, Ionata E, Marcolongo L, Vandenberghe LPDS, La Cara F, Faraco V. Optimization of Arundo donax Saccharification by (Hemi)cellulolytic Enzymes from Pleurotus ostreatus. BIOMED RESEARCH INTERNATIONAL 2015; 2015:951871. [PMID: 26634214 PMCID: PMC4652331 DOI: 10.1155/2015/951871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/17/2015] [Accepted: 10/01/2015] [Indexed: 11/26/2022]
Abstract
An enzymatic mixture of cellulases and xylanases was produced by Pleurotus ostreatus using microcrystalline cellulose as inducer, partially characterized and tested in the statistical analysis of Arundo donax bioconversion. The Plackett-Burman screening design was applied to identify the most significant parameters for the enzymatic hydrolysis of pretreated A. donax. As the most significant influence during the enzymatic hydrolysis of A. donax was exercised by the temperature (°C), pH, and time, the combined effect of these factors in the bioconversion by P. ostreatus cellulase and xylanase was analyzed by a 3(3) factorial experimental design. It is worth noting that the best result of 480.10 mg of sugars/gds, obtained at 45 °C, pH 3.5, and 96 hours of incubation, was significant also when compared with the results previously reached by process optimization with commercial enzymes.
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Affiliation(s)
- Rossana Liguori
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Elena Ionata
- Institute of Agro-Environment and Forest Biology, National Research Council (CNR), Via Pietro Castellino 111, 80131 Naples, Italy
| | - Loredana Marcolongo
- Institute of Agro-Environment and Forest Biology, National Research Council (CNR), Via Pietro Castellino 111, 80131 Naples, Italy
| | - Luciana Porto de Souza Vandenberghe
- Department of Bioprocess Engineering and Biotechnology, Federal University of Paraná, Coronel Francisco H. dos Santos Avenue 210, 81531-990 Curitiba, PR, Brazil
| | - Francesco La Cara
- Institute of Agro-Environment and Forest Biology, National Research Council (CNR), Via Pietro Castellino 111, 80131 Naples, Italy
| | - Vincenza Faraco
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
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Strategic optimization of xylanase–mannanase combi-CLEAs for synergistic and efficient hydrolysis of complex lignocellulosic substrates. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.02.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Thite V, Nerurkar A. Xylanases of Bacillus
spp. isolated from ruminant dung as potential accessory enzymes for agro-waste saccharification. Lett Appl Microbiol 2015; 60:456-66. [DOI: 10.1111/lam.12397] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/29/2014] [Accepted: 01/06/2015] [Indexed: 11/28/2022]
Affiliation(s)
- V.S. Thite
- Department of Microbiology and Biotechnology Centre; Faculty of Science; The Maharaja Sayajirao University of Baroda; Vadodara Gujarat India
| | - A.S. Nerurkar
- Department of Microbiology and Biotechnology Centre; Faculty of Science; The Maharaja Sayajirao University of Baroda; Vadodara Gujarat India
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Penicillium canescens Host as the Platform for Development of a New Recombinant Strain Producers of Carbohydrases. MICROORGANISMS IN BIOREFINERIES 2015. [DOI: 10.1007/978-3-662-45209-7_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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37
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Inoue H, Kishishita S, Kumagai A, Kataoka M, Fujii T, Ishikawa K. Contribution of a family 1 carbohydrate-binding module in thermostable glycoside hydrolase 10 xylanase from Talaromyces cellulolyticus toward synergistic enzymatic hydrolysis of lignocellulose. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:77. [PMID: 26000036 PMCID: PMC4440266 DOI: 10.1186/s13068-015-0259-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 04/29/2015] [Indexed: 05/10/2023]
Abstract
BACKGROUND Enzymatic removal of hemicellulose components such as xylan is an important factor for maintaining high glucose conversion from lignocelluloses subjected to low-severity pretreatment. Supplementation of xylanase in the cellulase mixture enhances glucose release from pretreated lignocellulose. Filamentous fungi produce multiple xylanases in their cellulase system, and some of them have modular structures consisting of a catalytic domain and a family 1 carbohydrate-binding module (CBM1). However, the role of CBM1 in xylanase in the synergistic hydrolysis of lignocellulose has not been investigated in depth. RESULTS Thermostable endo-β-1,4-xylanase (Xyl10A) from Talaromyces cellulolyticus, which is recognized as one of the core enzymes in the fungal cellulase system, has a modular structure consisting of a glycoside hydrolase family 10 catalytic domain and CBM1 at the C-terminus separated by a linker region. Three recombinant Xyl10A variants, that is, intact Xyl10A (Xyl10Awt), CBM1-deleted Xyl10A (Xyl10AdC), and CBM1 and linker region-deleted Xyl10A (Xyl10AdLC), were constructed and overexpressed in T. cellulolyticus. Cellulose-binding ability of Xyl10A CBM1 was demonstrated using quartz crystal microbalance with dissipation monitoring. Xyl10AdC and Xyl10AdLC showed relatively high catalytic activities for soluble and insoluble xylan substrates, whereas Xyl10Awt was more effective in xylan hydrolysis of wet disc-mill treated rice straw (WDM-RS). The enzyme mixture of cellulase monocomponents and intact or mutant Xyl10A enhanced the hydrolysis of WDM-RS glucan, with the most efficient synergism found in the interactions with Xyl10Awt. The increased glucan hydrolysis yield exhibited a linear relationship with the xylan hydrolysis yield by each enzyme. This relationship revealed significant hydrolysis of WDM-RS glucan with lower supplementation of Xyl10Awt. CONCLUSIONS Our results suggest that Xyl10A CBM1 has the following two roles in synergistic hydrolysis of lignocellulose by Xyl10A and cellulases: enhancement of lignocellulosic xylan hydrolysis by binding to cellulose, and the efficient removal of xylan obstacles that interrupt the cellulase activity (because of similar binding target of CBM1). The combination of CBM-containing cellulases and xylanases in a fugal cellulase system could contribute to reduction of the enzyme loading in the hydrolysis of pretreated lignocelluloses.
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Affiliation(s)
- Hiroyuki Inoue
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Seiichiro Kishishita
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Akio Kumagai
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Misumi Kataoka
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Tatsuya Fujii
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Kazuhiko Ishikawa
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
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Ye Z, Zheng Y, Li B, Borrusch MS, Storms R, Walton JD. Enhancement of synthetic Trichoderma-based enzyme mixtures for biomass conversion with an alternative family 5 glycosyl hydrolase from Sporotrichum thermophile. PLoS One 2014; 9:e109885. [PMID: 25295862 PMCID: PMC4190410 DOI: 10.1371/journal.pone.0109885] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 09/01/2014] [Indexed: 11/24/2022] Open
Abstract
Enzymatic conversion of lignocellulosic materials to fermentable sugars is a limiting step in the production of biofuels from biomass. We show here that combining enzymes from different microbial sources is one way to identify superior enzymes. Extracts of the thermophilic fungus Sporotrichum thermophile (synonym Myceliophthora thermophila) gave synergistic release of glucose (Glc) and xylose (Xyl) from pretreated corn stover when combined with an 8-component synthetic cocktail of enzymes from Trichoderma reesei. The S. thermophile extracts were fractionated and an enhancing factor identified as endo-β1,4-glucanase (StCel5A or EG2) of subfamily 5 of Glycosyl Hydrolase family 5 (GH5_5). In multi-component optimization experiments using a standard set of enzymes and either StCel5A or the ortholog from T. reesei (TrCel5A), reactions containing StCel5A yielded more Glc and Xyl. In a five-component optimization experiment (i.e., varying four core enzymes and the source of Cel5A), the optimal proportions for TrCel5A vs. StCel5A were similar for Glc yields, but markedly different for Xyl yields. Both enzymes were active on lichenan, glucomannan, and oat β-glucan; however, StCel5A but not TrCel5A was also active on β1,4-mannan, two types of galactomannan, and β1,4-xylan. Phylogenetically, fungal enzymes in GH5_5 sorted into two clades, with StCel5A and TrCel5A belonging to different clades. Structural differences with the potential to account for the differences in performance were deduced based on the known structure of TrCel5A and a homology-based model of StCel5A, including a loop near the active site of TrCel5A and the presence of four additional Trp residues in the active cleft of StCel5A. The results indicate that superior biomass-degrading enzymes can be identified by exploring taxonomic diversity combined with assays in the context of realistic enzyme combinations and realistic substrates. Substrate range may be a key factor contributing to superior performance within GH5_5.
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Affiliation(s)
- Zhuoliang Ye
- Department of Energy Great Lakes Bioenergy Research Center and Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Yun Zheng
- Centre for Structural and Functional Genomics, Concordia University, Montréal, Quebec, Canada
| | - Bingyao Li
- Department of Energy Great Lakes Bioenergy Research Center and Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Melissa S. Borrusch
- Department of Energy Great Lakes Bioenergy Research Center and Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Reginald Storms
- Centre for Structural and Functional Genomics, Concordia University, Montréal, Quebec, Canada
| | - Jonathan D. Walton
- Department of Energy Great Lakes Bioenergy Research Center and Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
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Čater M, Zorec M, Marinšek Logar R. Methods for Improving Anaerobic Lignocellulosic Substrates Degradation for Enhanced Biogas Production. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s40362-014-0019-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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40
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Marcolongo L, Ionata E, La Cara F, Amore A, Giacobbe S, Pepe O, Faraco V. The effect of Pleurotus ostreatus arabinofuranosidase and its evolved variant in lignocellulosic biomasses conversion. Fungal Genet Biol 2014; 72:162-167. [PMID: 25046861 DOI: 10.1016/j.fgb.2014.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
The fungal arabinofuranosidase from Pleurotus ostreatus PoAbf recombinantly expressed in Pichia pastoris rPoAbf and its evolved variant rPoAbf F435Y/Y446F were tested for their effectiveness to enhance the enzymatic saccharification of three lignocellulosic biomasses, namely Arundo donax, corn cobs and brewer's spent grains (BSG), after chemical or chemical-physical pretreatment. All the raw materials were subjected to an alkaline pretreatment by soaking in aqueous ammonia solution whilst the biomass from A. donax was also pretreated by steam explosion. The capability of the wild-type and mutant rPoAbf to increase the fermentable sugars recovery was assessed by using these enzymes in combination with different (hemi)cellulolytic activities. These enzymatic mixtures were either entirely of commercial origin or contained the cellulase from Streptomyces sp. G12 CelStrep recombinantly expressed in Escherichia coli in substitution to the commercial counterparts. The addition of the arabinofuranosidases from P. ostreatus improved the hydrolytic efficiency of the commercial enzymatic cocktails on all the pretreated biomasses. The best results were obtained using the rPoAbf evolved variant and are represented by increases of the xylose recovery up to 56.4%. These data clearly highlight the important role of the accessory hemicellulolytic activities to optimize the xylan bioconversion yields.
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Affiliation(s)
- Loredana Marcolongo
- Institute of Biosciences and BioResources, National Research Council, Napoli, Italy
| | - Elena Ionata
- Institute of Biosciences and BioResources, National Research Council, Napoli, Italy
| | - Francesco La Cara
- Institute of Biosciences and BioResources, National Research Council, Napoli, Italy
| | - Antonella Amore
- Department of Chemical Sciences, University of Naples "Federico II", Napoli, Italy
| | - Simona Giacobbe
- Department of Chemical Sciences, University of Naples "Federico II", Napoli, Italy
| | - Olimpia Pepe
- Department of Agriculture, University of Naples "Federico II", Portici (Napoli), Italy
| | - Vincenza Faraco
- Department of Chemical Sciences, University of Naples "Federico II", Napoli, Italy.
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Magnetic cross-linked enzyme aggregates (CLEAs): A novel concept towards carrier free immobilization of lignocellulolytic enzymes. Enzyme Microb Technol 2014; 61-62:17-27. [DOI: 10.1016/j.enzmictec.2014.04.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 04/10/2014] [Accepted: 04/17/2014] [Indexed: 11/21/2022]
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42
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Zhang Y, Xu B, Zhou W. On a novel mechanistic model for simultaneous enzymatic hydrolysis of cellulose and hemicellulose considering morphology. Biotechnol Bioeng 2014; 111:1767-81. [DOI: 10.1002/bit.25244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 02/07/2014] [Accepted: 03/19/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Yang Zhang
- Department of Chemical Engineering; Michigan Technological University; Houghton Michigan 49931
| | - Bingqian Xu
- Engineering and Nanoscale Science and Engineering Center; University of Georgia; Athens Georgia 30602
| | - Wen Zhou
- Department of Chemical Engineering; Michigan Technological University; Houghton Michigan 49931
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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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Kumar R, Wyman CE. Strong cellulase inhibition by Mannan polysaccharides in cellulose conversion to sugars. Biotechnol Bioeng 2014; 111:1341-53. [PMID: 24522973 DOI: 10.1002/bit.25218] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 01/24/2014] [Accepted: 02/06/2014] [Indexed: 11/08/2022]
Abstract
Cellulase enzymes contribute a major fraction of the total cost for biological conversion of lignocellulosic biomass to fuels and chemicals. Although a several fold reduction in cellulase production costs and enhancement of cellulase activity and stability have been reported in recent years, sugar yields are still lower at low enzyme doses than desired commercially. We recently reported that hemicellulose xylan and its oligomers strongly inhibit cellulase and that supplementation of cellulase with xylanase and β-xylosidase would significantly reduce such inhibition. In this study, mannan polysaccharides and their enzymatically prepared hydrolyzates were discovered to be strongly inhibitory to fungal cellulase in cellulose conversion (>50% drop in % relative conversion), even at a small concentration of 0.1 g/L, and inhibition was much greater than experienced by other known inhibitors such as cellobiose, xylooligomers, and furfural. Furthermore, cellulase inhibition dramatically increased with heteromannan loading and mannan substitution with galactose side units. In general, enzymatically prepared hydrolyzates were less inhibitory than their respective mannan polysaccharides except highly substituted ones. Supplementation of cellulase with commercial accessory enzymes such as xylanase, pectinase, and β-glucosidase was effective in greatly relieving inhibition but only for less substituted heteromannans. However, cellulase supplementation with purified heteromannan specific enzymes relieved inhibition by these more substituted heteromannans as well, suggesting that commercial preparations need to have higher amounts of such activities to realize high sugar yields at the low enzyme protein loadings needed for low cost fuels production.
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Affiliation(s)
- Rajeev Kumar
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, 1084 Columbia Avenue, Riverside, California, 92507; BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-6422.
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Mixtures of thermostable enzymes show high performance in biomass saccharification. Appl Biochem Biotechnol 2014; 173:1038-56. [PMID: 24752938 DOI: 10.1007/s12010-014-0893-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/25/2014] [Indexed: 10/25/2022]
Abstract
Optimal enzyme mixtures of six Trichoderma reesei enzymes and five thermostable enzyme components were developed for the hydrolysis of hydrothermally pretreated wheat straw, alkaline oxidised sugar cane bagasse and steam-exploded bagasse by statistically designed experiments. Preliminary studies to narrow down the optimization parameters showed that a cellobiohydrolase/endoglucanase (CBH/EG) ratio of 4:1 or higher of thermostable enzymes gave the maximal CBH-EG synergy in the hydrolysis of hydrothermally pretreated wheat straw. The composition of optimal enzyme mixtures depended clearly on the substrate and on the enzyme system studied. The optimal enzyme mixture of thermostable enzymes was dominated by Cel7A and required a relatively high amount of xylanase, whereas with T. reesei enzymes, the high proportion of Cel7B appeared to provide the required xylanase activity. The main effect of the pretreatment method was that the required proportion of xylanase was higher and the proportion of Cel7A lower in the optimized mixture for hydrolysis of alkaline oxidised bagasse than steam-exploded bagasse. In prolonged hydrolyses, less Cel7A was generally required in the optimal mixture. Five-component mixtures of thermostable enzymes showed comparable hydrolysis yields to those of commercial enzyme mixtures.
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Jabbour D, Angelos ER, Mukhopadhyay A, Womboldt A, Borrusch MS, Walton JD. Factors contributing to the recalcitrance of herbaceous dicotyledons (forbs) to enzymatic deconstruction. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:52. [PMID: 24708722 PMCID: PMC3992138 DOI: 10.1186/1754-6834-7-52] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 03/27/2014] [Indexed: 05/29/2023]
Abstract
BACKGROUND Many different feedstocks are under consideration for the practical production of biofuels from lignocellulosic materials. The best choice under any particular combination of economic, agronomic, and environmental conditions depends on multiple factors. The use of old fields, restored prairie, or marginal lands to grow biofuel feedstocks offers several potential benefits including minimal agronomic inputs, reduced competition with food production, and high biodiversity. However, a major component of such landscapes is often herbaceous dicotyledonous plants, also known as forbs. The potential and obstacles of using forbs as biofuel feedstocks compared to the more frequently considered grasses and woody plants are poorly understood. RESULTS The factors that contribute to the yield of fermentable sugars from four representative forbs were studied in comparison with corn stover. The forbs chosen for the study were lamb's quarters (Chenopodium album), goldenrod (Solidago canadensis), milkweed (Asclepias syriaca), and Queen Anne's lace (Daucus carota). These plants are taxonomically diverse, widely distributed in northern temperate regions including the continental United States, and are weedy but not invasive. All of the forbs had lower total glucose (Glc) content from all sources (cell walls, sucrose, starch, glucosides, and free Glc) compared to corn stover (range 16.2 to 23.0% on a dry weight basis compared to 39.2% for corn stover). When digested with commercial enzyme mixtures after alkaline pretreatment, yields of Glc as a percentage of total Glc were lower for the forbs compared to corn stover. Enzyme inhibition by water-extractable compounds was not a significant contributor to the lower yields. Based on experiments with optimized cocktails of pure glycosyl hydrolases, enzyme imbalance probably accounted for much of the lower yields. Addition of xyloglucanase and α-xylosidase, two enzymes targeting Glc-containing polysaccharides that are more abundant in dicotyledonous plants compared to grasses, enhanced Glc yields from lamb's quarters, but Glc yields were still lower than from corn stover. CONCLUSION The potential utilization of forb-rich plant communities as biofuel feedstocks must take into account their lower Glc content compared to grasses such as corn stover. Furthermore, new enzyme mixtures tailored to the different cell wall composition of forbs will have to be developed.
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Affiliation(s)
- Dina Jabbour
- Department of Energy, Great Lakes Bioenergy Research Center, 1129 Farm Lane, Michigan State University, East Lansing, MI 48824, USA
| | - Evan R Angelos
- Department of Energy, Great Lakes Bioenergy Research Center, 1129 Farm Lane, Michigan State University, East Lansing, MI 48824, USA
| | - Achira Mukhopadhyay
- Department of Energy, Great Lakes Bioenergy Research Center, 1129 Farm Lane, Michigan State University, East Lansing, MI 48824, USA
| | - Alec Womboldt
- Department of Energy, Great Lakes Bioenergy Research Center, 1129 Farm Lane, Michigan State University, East Lansing, MI 48824, USA
| | - Melissa S Borrusch
- Department of Energy, Great Lakes Bioenergy Research Center, 1129 Farm Lane, Michigan State University, East Lansing, MI 48824, USA
| | - Jonathan D Walton
- Department of Energy, Great Lakes Bioenergy Research Center, 1129 Farm Lane, Michigan State University, East Lansing, MI 48824, USA
- Department of Energy, Plant Research Laboratory, 612 Wilson Road, Michigan State University, East Lansing, MI 48824, USA
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Proskurina OV, Korotkova OG, Rozhkova AM, Matys VY, Koshelev AV, Okunev ON, Nemashkalov VA, Sinitsyna OA, Revin VV, Sinitsyn AP. Trichoderma reesei endoglucanase IV: A new component of biocatalysts based on the cellulase complex of the fungus Penicillium verruculosum for hydrolysis of cellulose-containing biomass. CATALYSIS IN INDUSTRY 2014. [DOI: 10.1134/s2070050414010085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Harris PV, Xu F, Kreel NE, Kang C, Fukuyama S. New enzyme insights drive advances in commercial ethanol production. Curr Opin Chem Biol 2014; 19:162-70. [DOI: 10.1016/j.cbpa.2014.02.015] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/08/2014] [Accepted: 02/12/2014] [Indexed: 01/19/2023]
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Inoue H, Decker SR, Taylor LE, Yano S, Sawayama S. Identification and characterization of core cellulolytic enzymes from Talaromyces cellulolyticus (formerly Acremonium cellulolyticus) critical for hydrolysis of lignocellulosic biomass. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:151. [PMID: 25342974 PMCID: PMC4196096 DOI: 10.1186/s13068-014-0151-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 09/25/2014] [Indexed: 05/10/2023]
Abstract
BACKGROUND Enzymatic hydrolysis of pretreated lignocellulosic biomass is an essential process for the production of fermentable sugars for industrial use. A better understanding of fungal cellulase systems will provide clues for maximizing the hydrolysis of target biomass. Talaromyces cellulolyticus is a promising fungus for cellulase production and efficient biomass hydrolysis. Several cellulolytic enzymes purified from T. cellulolyticus were characterized in earlier studies, but the core enzymes critical for hydrolysis of lignocellulosic biomass remain unknown. RESULTS Six cellulolytic enzymes critical for the hydrolysis of crystalline cellulose were purified from T. cellulolyticus culture supernatant using an enzyme assay based on synergistic hydrolysis of Avicel. The purified enzymes were identified by their substrate specificities and analyses of trypsin-digested peptide fragments and were classified into the following glycosyl hydrolase (GH) families: GH3 (β-glucosidase, Bgl3A), GH5 (endoglucanase, Cel5A), GH6 (cellobiohydrolase II, Cel6A), GH7 (cellobiohydrolase I and endoglucanase, Cel7A and Cel7B, respectively), and GH10 (xylanase, Xyl10A). Hydrolysis of dilute acid-pretreated corn stover (PCS) with mixtures of the purified enzymes showed that Cel5A, Cel7B, and Xyl10A each had synergistic effects with a mixture of Cel6A and Cel7A. Cel5A seemed to be more effective in the synergistic hydrolysis of the PCS than Cel7B. The ratio of Cel5A, Cel6A, Cel7A, and Xyl10A was statistically optimized for the hydrolysis of PCS glucan in the presence of Bgl3A. The resultant mixture achieved higher PCS glucan hydrolysis at lower enzyme loading than a culture filtrate from T. cellulolyticus or a commercial enzyme preparation, demonstrating that the five enzymes play a role as core enzymes in the hydrolysis of PCS glucan. CONCLUSIONS Core cellulolytic enzymes in the T. cellulolyticus cellulase system were identified to Cel5A, Cel6A, Cel7A, Xyl10A, and Bgl3A and characterized. The optimized mixture of these five enzymes was highly effective for the hydrolysis of PCS glucan, providing a foundation for future improvement of the T. cellulolyticus cellulase system.
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Affiliation(s)
- Hiroyuki Inoue
- />Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology, 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Stephen R Decker
- />Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401 USA
| | - Larry E Taylor
- />Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401 USA
| | - Shinichi Yano
- />Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology, 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 Japan
| | - Shigeki Sawayama
- />Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 Japan
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Fungal Beta-glucosidases: a bottleneck in industrial use of lignocellulosic materials. Biomolecules 2013; 3:612-31. [PMID: 24970184 PMCID: PMC4030957 DOI: 10.3390/biom3030612] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 08/17/2013] [Accepted: 08/20/2013] [Indexed: 12/16/2022] Open
Abstract
Profitable biomass conversion processes are highly dependent on the use of efficient enzymes for lignocellulose degradation. Among the cellulose degrading enzymes, beta-glucosidases are essential for efficient hydrolysis of cellulosic biomass as they relieve the inhibition of the cellobiohydrolases and endoglucanases by reducing cellobiose accumulation. In this review, we discuss the important role beta-glucosidases play in complex biomass hydrolysis and how they create a bottleneck in industrial use of lignocellulosic materials. An efficient beta-glucosidase facilitates hydrolysis at specified process conditions, and key points to consider in this respect are hydrolysis rate, inhibitors, and stability. Product inhibition impairing yields, thermal inactivation of enzymes, and the high cost of enzyme production are the main obstacles to commercial cellulose hydrolysis. Therefore, this sets the stage in the search for better alternatives to the currently available enzyme preparations either by improving known or screening for new beta-glucosidases.
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