1
|
Iglesias Rando MR, Gorojovsky N, Zylberman V, Goldbaum FA, Craig PO. Improvement of Cellulomonas fimi endoglucanase CenA by multienzymatic display on a decameric structural scaffold. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12581-6. [PMID: 37212884 DOI: 10.1007/s00253-023-12581-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/27/2023] [Accepted: 05/06/2023] [Indexed: 05/23/2023]
Abstract
The development of multifunctional particles using polymeric scaffolds is an emerging technology for many nanobiotechnological applications. Here we present a system for the production of multifunctional complexes, based on the high affinity non-covalent interaction of cohesin and dockerin modules complementary fused to decameric Brucella abortus lumazine synthase (BLS) subunits, and selected target proteins, respectively. The cohesin-BLS scaffold was solubly expressed in high yield in Escherichia coli, and revealed a high thermostability. The production of multienzymatic particles using this system was evaluated using the catalytic domain of Cellulomonas fimi endoglucanase CenA recombinantly fused to a dockerin module. Coupling of the enzyme to the scaffold was highly efficient and occurred with the expected stoichiometry. The decavalent enzymatic complexes obtained showed higher cellulolytic activity and association to the substrate compared to equivalent amounts of the free enzyme. This phenomenon was dependent on the multiplicity and proximity of the enzymes coupled to the scaffold, and was attributed to an avidity effect in the polyvalent enzyme interaction with the substrate. Our results highlight the usefulness of the scaffold presented in this work for the development of multifunctional particles, and the improvement of lignocellulose degradation among other applications. KEY POINTS: • New system for multifunctional particle production using the BLS scaffold • Higher cellulolytic activity of polyvalent endoglucanase compared to the free enzyme • Amount of enzyme associated to cellulose is higher for the polyvalent endoglucanase.
Collapse
Affiliation(s)
- Matías R Iglesias Rando
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160 (CP 1428), Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Intendente Güiraldes 2160 (CP 1428), Buenos Aires, Argentina
| | - Natalia Gorojovsky
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160 (CP 1428), Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Intendente Güiraldes 2160 (CP 1428), Buenos Aires, Argentina
| | - Vanesa Zylberman
- Inmunova SA, Gral. San Martín, 25 de Mayo 1021 (CP 1650), Villa Lynch, Buenos Aires, Argentina
| | - Fernando A Goldbaum
- Inmunova SA, Gral. San Martín, 25 de Mayo 1021 (CP 1650), Villa Lynch, Buenos Aires, Argentina
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435 (CP 1405), Buenos Aires, Argentina
- Centro de Rediseño e Ingeniería de Proteínas (CRIP), UNSAM Campus Miguelete, 25 de Mayo y Francia (CP 1650), Gral. San Martín, Buenos Aires, Argentina
| | - Patricio O Craig
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160 (CP 1428), Buenos Aires, Argentina.
- CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Intendente Güiraldes 2160 (CP 1428), Buenos Aires, Argentina.
| |
Collapse
|
2
|
Kuch NJ, Kutschke ME, Parker A, Bingman CA, Fox BG. Contribution of calcium ligands in substrate binding and product release in the Acetovibrio thermocellus glycoside hydrolase family 9 cellulase CelR. J Biol Chem 2023; 299:104655. [PMID: 36990218 PMCID: PMC10149213 DOI: 10.1016/j.jbc.2023.104655] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Enzymatic deconstruction of lignocellulosic biomass is crucial to establishment of the renewable biofuel and bioproduct economy. Better understanding of these enzymes, including their catalytic and binding domains, and other features offer potential avenues for improvement. Glycoside hydrolase family 9 (GH9) enzymes are attractive targets because they have members that exhibit exo- and endo-cellulolytic activity, processivity of reaction, and thermostability. This study examines a GH9 from Acetovibrio thermocellus ATCC 27405, AtCelR containing a catalytic domain and a carbohydrate binding module (CBM3c). Crystal structures of the enzyme without substrate, bound to cellohexaose (substrate) or cellobiose (product), show the positioning of ligands to calcium and adjacent residues in the catalytic domain that may contribute to substrate binding and facilitate product release. We also investigated the properties of the enzyme engineered to contain an additional carbohydrate binding module (CBM3a). Relative to the catalytic domain alone, CBM3a gave improved binding for Avicel (a crystalline form of cellulose), and catalytic efficiency (kcat/KM) was improved 40× with both CBM3c and CBM3a present. However, because of the molecular weight added by CBM3a, the specific activity of the engineered enzyme was not increased relative to the native construct consisting of only the catalytic and CBM3c domains. This work provides new insight into a potential role of the conserved calcium in the catalytic domain and identifies contributions and limitations of domain engineering for AtCelR and perhaps other GH9 enzymes.
Collapse
Affiliation(s)
- Nathaniel J Kuch
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mark E Kutschke
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Alex Parker
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; Dane County Youth Apprenticeship Program, Dane County School Consortium, Monona, Wisconsin, USA
| | - Craig A Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; Collaborative Crystallography Core, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brian G Fox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA.
| |
Collapse
|
3
|
Clostridium thermocellum as a Promising Source of Genetic Material for Designer Cellulosomes: An Overview. Catalysts 2021. [DOI: 10.3390/catal11080996] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Plant biomass-based biofuels have gradually substituted for conventional energy sources thanks to their obvious advantages, such as renewability, huge quantity, wide availability, economic feasibility, and sustainability. However, to make use of the large amount of carbon sources stored in the plant cell wall, robust cellulolytic microorganisms are highly demanded to efficiently disintegrate the recalcitrant intertwined cellulose fibers to release fermentable sugars for microbial conversion. The Gram-positive, thermophilic, cellulolytic bacterium Clostridium thermocellum possesses a cellulolytic multienzyme complex termed the cellulosome, which has been widely considered to be nature’s finest cellulolytic machinery, fascinating scientists as an auspicious source of saccharolytic enzymes for biomass-based biofuel production. Owing to the supra-modular characteristics of the C. thermocellum cellulosome architecture, the cellulosomal components, including cohesin, dockerin, scaffoldin protein, and the plentiful cellulolytic and hemicellulolytic enzymes have been widely used for constructing artificial cellulosomes for basic studies and industrial applications. In addition, as the well-known microbial workhorses are naïve to biomass deconstruction, several research groups have sought to transform them from non-cellulolytic microbes into consolidated bioprocessing-enabling microbes. This review aims to update and discuss the current progress in these mentioned issues, point out their limitations, and suggest some future directions.
Collapse
|
4
|
McConnell SA, Cannon KA, Morgan C, McAllister R, Amer BR, Clubb RT, Yeates TO. Designed Protein Cages as Scaffolds for Building Multienzyme Materials. ACS Synth Biol 2020; 9:381-391. [PMID: 31922719 DOI: 10.1021/acssynbio.9b00407] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The functions of enzymes can be strongly affected by their higher-order spatial arrangements. In this study we combine multiple new technologies-designer protein cages and sortase-based enzymatic attachments between proteins-as a novel platform for organizing multiple enzymes (of one or more types) in specified configurations. As a scaffold we employ a previously characterized 24-subunit designed protein cage whose termini are outwardly exposed for attachment. As a first-use case, we test the attachment of two cellulase enzymes known to act synergistically in cellulose degradation. We show that, after endowing the termini of the cage subunits with a short "sort-tag" sequence (LPXTG) and the opposing termini of the cellulase enzymes with a short polyglycine sequence tag, addition of sortase covalently attaches the enzymes to the cage with good reactivity and high copy number. The doubly modified cages show enhanced activity in a cellulose degradation assay compared to enzymes in solution, and compared to a combination of singly modified cages. These new engineering strategies could be broadly useful in the development of enzymatic material and synthetic biology applications.
Collapse
Affiliation(s)
- Scott A. McConnell
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Molecular Biology Institute, University of California, Los Angeles, California 90095, United States
| | - Kevin A. Cannon
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Christian Morgan
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095, United States
| | - Rachel McAllister
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Brendan R. Amer
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Molecular Biology Institute, University of California, Los Angeles, California 90095, United States
| | - Robert T. Clubb
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Molecular Biology Institute, University of California, Los Angeles, California 90095, United States
| | - Todd O. Yeates
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Molecular Biology Institute, University of California, Los Angeles, California 90095, United States
| |
Collapse
|
5
|
Pason P, Sermsathanaswadi J, Waeonukul R, Tachaapaikoon C, Baramee S, Ratanakhanokchai K, Kosugi A. Molecular characterization of hypothetical scaffolding-like protein S1 in multienzyme complex produced by Paenibacillus curdlanolyticus B-6. AMB Express 2019; 9:171. [PMID: 31673804 PMCID: PMC6823336 DOI: 10.1186/s13568-019-0896-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/15/2019] [Indexed: 11/24/2022] Open
Abstract
Paenibacillus curdlanolyticus B-6 produces an extracellular multienzyme complex containing a hypothetical scaffolding-like protein and several xylanases and cellulases. The largest (280-kDa) component protein, called S1, has cellulose-binding ability and xylanase activity, thus was considered to function like the scaffolding proteins found in cellulosomes. S1 consists of 863 amino acid residues with predicted molecular mass 91,029 Da and includes two N-terminal surface layer homology (SLH) domains, but most of its sequence shows no homology with proteins of known function. Native S1 (nS1) was highly glycosylated. Purified nS1 and recombinant Xyn11A (rXyn11A) as a major xylanase subunit could assemble in a complex, but recombinant S1 (rS1) could not interact with rXyn11A, indicating that S1 glycosylation is necessary for assembly of the multienzyme complex. nS1 and rS1 showed weak, typical endo-xylanase activity, even though they have no homology with known glycosyl hydrolase family enzymes. S1 and its SLH domains bound tightly to the peptide-glycan layer of P. curdlanolyticus B-6, microcrystalline cellulose, and insoluble xylan, indicating that the SLHs of S1 bind to carbohydrate polymers and the cell surface. When nS1 and rXyn11A were co-incubated with birchwood xylan, the degradation ability was synergistically increased compared with that for each protein; however synergy was not observed for rS1 and rXynA. These results indicate that S1 may have a scaffolding protein-like function by interaction with enzyme subunits and polysaccharides through its glycosylated sites and SLH domains.
Collapse
|
6
|
Hirano K, Saito T, Shinoda S, Haruki M, Hirano N. In vitro assembly and cellulolytic activity of a β-glucosidase-integrated cellulosome complex. FEMS Microbiol Lett 2019; 366:5581498. [DOI: 10.1093/femsle/fnz209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/02/2019] [Indexed: 11/13/2022] Open
Abstract
ABSTRACTThe cellulosome is a supramolecular multi-enzyme complex formed by protein interactions between the cohesin modules of scaffoldin proteins and the dockerin module of various polysaccharide-degrading enzymes. In general, the cellulosome exhibits no detectable β-glucosidase activity to catalyze the conversion of cellobiose to glucose. Because β-glucosidase prevents product inhibition of cellobiohydrolase by cellobiose, addition of β-glucosidase to the cellulosome greatly enhances the saccharification of crystalline cellulose and plant biomass. Here, we report the in vitro assembly and cellulolytic activity of a β-glucosidase-coupled cellulosome complex comprising the three major cellulosomal cellulases and full-length scaffoldin protein of Clostridium (Ruminiclostridium) thermocellum, and Thermoanaerobacter brockii β-glucosidase fused to the type-I dockerin module of C. thermocellum. We show that the cellulosome complex composed of nearly equal numbers of cellulase and β-glucosidase molecules exhibits maximum activity toward crystalline cellulose, and saccharification activity decreases as the enzymatic ratio of β-glucosidase increases. Moreover, β-glucosidase-coupled and β-glucosidase-supplemented cellulosome complexes similarly exhibit maximum activity toward crystalline cellulose (i.e. 1.7-fold higher than that of the β-glucosidase-free cellulosome complex). These results suggest that the enzymatic ratio of cellulase and β-glucosidase in the assembled complex is crucial for the efficient saccharification of crystalline cellulose by the β-glucosidase-integrated cellulosome complex.
Collapse
Affiliation(s)
- Katsuaki Hirano
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan
| | - Tsubasa Saito
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan
| | - Suguru Shinoda
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan
| | - Mitsuru Haruki
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan
| | - Nobutaka Hirano
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan
| |
Collapse
|
7
|
Hu B, Zhu M. Reconstitution of cellulosome: Research progress and its application in biorefinery. Biotechnol Appl Biochem 2019; 66:720-730. [DOI: 10.1002/bab.1804] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 08/03/2019] [Indexed: 09/01/2023]
Affiliation(s)
- Bin‐Bin Hu
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals School of Biology and Biological Engineering South China University of Technology, Guangzhou Higher Education Mega Center Panyu Guangzhou People's Republic of China
- Yunnan Academy of Tobacco Agricultural Sciences Kunming People's Republic of China
- State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou People's Republic of China
| | - Ming‐Jun Zhu
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals School of Biology and Biological Engineering South China University of Technology, Guangzhou Higher Education Mega Center Panyu Guangzhou People's Republic of China
- State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou People's Republic of China
- College of Life and Geographic Sciences Kashi University Kashi People's Republic of China
- The Key Laboratory of Ecology and Biological Resources in Yarkand Oasis at Colleges & Universities under the Department of Education of Xinjiang Uygur Autonomous Region Kashi University Kashi People's Republic of China
| |
Collapse
|
8
|
Comparative Biochemical Analysis of Cellulosomes Isolated from Clostridium clariflavum DSM 19732 and Clostridium thermocellum ATCC 27405 Grown on Plant Biomass. Appl Biochem Biotechnol 2018; 187:994-1010. [DOI: 10.1007/s12010-018-2864-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/13/2018] [Indexed: 12/12/2022]
|
9
|
Leis B, Held C, Andreeßen B, Liebl W, Graubner S, Schulte LP, Schwarz WH, Zverlov VV. Optimizing the composition of a synthetic cellulosome complex for the hydrolysis of softwood pulp: identification of the enzymatic core functions and biochemical complex characterization. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:220. [PMID: 30116297 PMCID: PMC6083626 DOI: 10.1186/s13068-018-1220-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/31/2018] [Indexed: 05/30/2023]
Abstract
BACKGROUND The development of efficient cellulase blends is a key factor for cost-effectively valorizing biomass in a new bio-economy. Today, the enzymatic hydrolysis of plant-derived polysaccharides is mainly accomplished with fungal cellulases, whereas potentially equally effective cellulose-degrading systems from bacteria have not been developed. Particularly, a thermostable multi-enzyme cellulase complex, the cellulosome from the anaerobic cellulolytic bacterium Clostridium thermocellum is promising of being applied as cellulolytic nano-machinery for the production of fermentable sugars from cellulosic biomass. RESULTS In this study, 60 cellulosomal components were recombinantly produced in E. coli and systematically permuted in synthetic complexes to study the function-activity relationship of all available enzymes on Kraft pulp from pine wood as the substrate. Starting from a basic exo/endoglucanase complex, we were able to identify additional functional classes such as mannanase and xylanase for optimal activity on the substrate. Based on these results, we predicted a synthetic cellulosome complex consisting of seven single components (including the scaffoldin protein and a β-glucosidase) and characterized it biochemically. We obtained a highly thermostable complex with optimal activity around 60-65 °C and an optimal pH in agreement with the optimum of the native cellulosome (pH 5.8). Remarkably, a fully synthetic complex containing 47 single cellulosomal components showed comparable activity with a commercially available fungal enzyme cocktail on the softwood pulp substrate. CONCLUSIONS Our results show that synthetic bacterial multi-enzyme complexes based on the cellulosome of C. thermocellum can be applied as a versatile platform for the quick adaptation and efficient degradation of a substrate of interest.
Collapse
Affiliation(s)
- Benedikt Leis
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Present Address: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchester Str. 2, 35394 Gießen, Germany
| | - Claudia Held
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Björn Andreeßen
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang Liebl
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Sigrid Graubner
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Louis-Philipp Schulte
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang H. Schwarz
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Vladimir V. Zverlov
- Department of Microbiology, Technische Universität München, TUM School of Life Sciences Weihenstephan, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 2, Moscow, 123182 Russia
| |
Collapse
|
10
|
Li R, Feng Y, Liu S, Qi K, Cui Q, Liu YJ. Inducing effects of cellulosic hydrolysate components of lignocellulose on cellulosome synthesis in Clostridium thermocellum. Microb Biotechnol 2018; 11:905-916. [PMID: 29943510 PMCID: PMC6116742 DOI: 10.1111/1751-7915.13293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/25/2018] [Accepted: 06/04/2018] [Indexed: 02/06/2023] Open
Abstract
Cellulosome is a highly efficient supramolecular machine for lignocellulose degradation, and its substrate‐coupled regulation requires soluble transmembrane signals. However, the inducers for cellulosome synthesis and the inducing effect have not been clarified quantitatively. Values of cellulosome production capacity (CPC) and estimated specific activity (eSA) were calculated based on the primary scaffoldin ScaA to define the stimulating effects on the cellulosome synthesis in terms of quantity and quality respectively. The estimated cellulosome production of Clostridium thermocellum on glucose was at a low housekeeping level. Both Avicel and cellobiose increased CPCs of the cells instead of the eSAs of the cellulosome. The CPC of Avicel‐grown cells was over 20‐fold of that of glucose‐grown cells, while both Avicel‐ and glucose‐derived cellulosomes showed similar eSA. The CPC of cellobiose‐grown cells was also over three times higher than glucose‐grown cells, but the eSA of cellobiose‐derived cellulosome was 16% lower than that of the glucose‐derived cellulosome. Our results indicated that cello‐oligosaccharides played the key roles in inducing the synthesis of the cellulosome, but non‐cellulosic polysaccharides showed no inducing effects.
Collapse
Affiliation(s)
- Renmin Li
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Shiyue Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Kuan Qi
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| |
Collapse
|
11
|
Do TH, Le NG, Dao TK, Nguyen TMP, Le TL, Luu HL, Nguyen KHV, Nguyen VL, Le LA, Phung TN, van Straalen NM, Roelofs D, Truong NH. Metagenomic insights into lignocellulose-degrading genes through Illumina-based de novo sequencing of the microbiome in Vietnamese native goats' rumen. J GEN APPL MICROBIOL 2018. [PMID: 29526926 DOI: 10.2323/jgam.2017.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The scarcity of enzymes having an optimal activity in lignocellulose deconstruction is an obstacle for industrial-scale conversion of cellulosic biomass into biofuels. With the aim of mining novel lignocellulolytic enzymes, a ~9 Gb metagenome of bacteria in Vietnamese native goats' rumen was sequenced by Illumina platform. From the data, 821 ORFs encoding carbohydrate esterases (CEs) and polysaccharide lyases (PLs) serving for lignocellulose pre-treatment, 816 ORFs encoding 11 glycoside hydrolase families (GHs) of cellulases, and 2252 ORFs encoding 22 GHs of hemicellulases, were mined. The carbohydrate binding module (CBM) was also abundant with 763 ORFs, of which 480 ORFs are located with lignocellulolytic enzymes. The enzyme modularity analysis showed that CBMs are usually present in endoglucanase, endo 1,3-beta-D-glucosidase, and endoxylanase, whereas fibronectin 3-like module (FN3) mainly represents in GH3 and immunoglobulin-like domain (Ig) was located in GH9 only. Every domain located in each ORF was analyzed in detail to contribute enzymes' modularity which is valuable for modelling, to study the structure, and for recombinant production. With the aim of confirming the annotated results, a mined ORF encoding CBM63 was highly expressed in E. coli in soluble form. The purified recombinant CBM63 exhibited no cellulase activity, but enhanced a commercial cellulase activity in the destruction of a paper filter.
Collapse
Affiliation(s)
- Thi Huyen Do
- Institute of Biotechnology, Vietnam Academy of Science and Technology.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology
| | - Ngoc Giang Le
- Institute of Biotechnology, Vietnam Academy of Science and Technology.,Department of Ecological Science, Vrije Universiteit Amsterdam
| | - Trong Khoa Dao
- Institute of Biotechnology, Vietnam Academy of Science and Technology.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology
| | | | - Tung Lam Le
- Institute of Biotechnology, Vietnam Academy of Science and Technology
| | - Han Ly Luu
- Institute of Biotechnology, Vietnam Academy of Science and Technology
| | - Khanh Hoang Viet Nguyen
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology.,Institute of New Technology/Academy of Military Science and Technology
| | - Van Lam Nguyen
- Institute of Biotechnology, Vietnam Academy of Science and Technology.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology
| | - Lan Anh Le
- Institute of Biotechnology, Vietnam Academy of Science and Technology
| | - Thu Nguyet Phung
- Institute of Biotechnology, Vietnam Academy of Science and Technology
| | | | - Dick Roelofs
- Department of Ecological Science, Vrije Universiteit Amsterdam
| | - Nam Hai Truong
- Institute of Biotechnology, Vietnam Academy of Science and Technology.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology
| |
Collapse
|
12
|
Liu YJ, Liu S, Dong S, Li R, Feng Y, Cui Q. Determination of the native features of the exoglucanase Cel48S from Clostridium thermocellum. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:6. [PMID: 29344087 PMCID: PMC5766998 DOI: 10.1186/s13068-017-1009-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/29/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Clostridium thermocellum is considered one of the most efficient natural cellulose degraders because of its cellulosomal system. As the major exoglucanase of cellulosome in C. thermocellum, Cel48S plays key roles and influences the activity and features of cellulosome to a great extent. Thus, it is of great importance to reveal the enzymatic features of Cel48S. However, Cel48S has not been well performed due to difficulties in purifying either recombinant or native Cel48S proteins. RESULTS We observed that the soluble fraction of the catalytic domain of Cel48S (Cel48S_CD) obtained by heterologous expression in Escherichia coli and denaturation-refolding treatment contained a large portion of incorrectly folded proteins with low activity. Using a previously developed seamless genome-editing system for C. thermocellum, we achieved direct purification of Cel48S_CD from the culture supernatant of C. thermocellum DSM1313 by inserting a sequence encoding 12 successive histidine residues and a TAA stop codon immediately behind the GH domain of Cel48S. Based on the fully active protein, biochemical and structural analyses were performed to reveal its innate characteristics. The native Cel48S_CD showed high activity of 117.61 ± 2.98 U/mg and apparent substrate preference for crystalline cellulose under the assay conditions. The crystal structure of the native GH48 protein revealed substrate-coupled changes in the residue conformation, indicating induced-fit effects between Cel48S_CD and substrates. Mass spectrum and crystal structural analyses suggested no significant posttranslational modification in the native Cel48S_CD protein. CONCLUSION Our results confirmed that the high activity and substrate specificity of Cel48S_CD from C. thermocellum were consistent with its importance in the cellulosome. The structure of the native Cel48S_CD protein revealed evidence of conformational changes during substrate binding. In addition, our study provided a reliable method for in situ purification of cellulosomal and other secretive proteins from C. thermocellum.
Collapse
Affiliation(s)
- Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Shiyue Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Sheng Dong
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Renmin Li
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| |
Collapse
|
13
|
Jia L, Minamihata K, Ichinose H, Tsumoto K, Kamiya N. Polymeric SpyCatcher Scaffold Enables Bioconjugation in a Ratio-Controllable Manner. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201700195] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 09/16/2017] [Indexed: 01/05/2023]
Affiliation(s)
- Lili Jia
- Department of Applied Chemistry; Graduate School of Engineering; Kyushu University; 744 Motooka Fukuoka 819-0395 Japan
| | - Kosuke Minamihata
- Department of Applied Chemistry; Graduate School of Engineering; Kyushu University; 744 Motooka Fukuoka 819-0395 Japan
| | - Hirofumi Ichinose
- Faculty of Agriculture; Kyushu University; Hakozaki 6-10-1 Higashi-ku Fukuoka 812-8581 Japan
| | - Kouhei Tsumoto
- Department of Chemistry and Biotechnology; The University of Tokyo; 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan
| | - Noriho Kamiya
- Department of Applied Chemistry; Graduate School of Engineering; Kyushu University; 744 Motooka Fukuoka 819-0395 Japan
- Division of Biotechnology; Center for Future Chemistry; Kyushu University; Fukuoka 819-0388 Japan
| |
Collapse
|
14
|
Orita T, Sakka M, Kimura T, Sakka K. Recombinant cellulolytic or xylanolytic complex comprising the full-length scaffolding protein RjCipA and cellulase RjCel5B or xylanase RjXyn10C of Ruminiclostridium josui. Enzyme Microb Technol 2017; 97:63-70. [DOI: 10.1016/j.enzmictec.2016.10.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/14/2016] [Accepted: 10/30/2016] [Indexed: 11/26/2022]
|
15
|
Leis B, Held C, Bergkemper F, Dennemarck K, Steinbauer R, Reiter A, Mechelke M, Moerch M, Graubner S, Liebl W, Schwarz WH, Zverlov VV. Comparative characterization of all cellulosomal cellulases from Clostridium thermocellum reveals high diversity in endoglucanase product formation essential for complex activity. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:240. [PMID: 29075324 PMCID: PMC5651568 DOI: 10.1186/s13068-017-0928-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/10/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Clostridium thermocellum is a paradigm for efficient cellulose degradation and a promising organism for the production of second generation biofuels. It owes its high degradation rate on cellulosic substrates to the presence of supra-molecular cellulase complexes, cellulosomes, which comprise over 70 different single enzymes assembled on protein-backbone molecules of the scaffold protein CipA. RESULTS Although all 24 single-cellulosomal cellulases were described previously, we present the first comparative catalogue of all these enzymes together with a comprehensive analysis under identical experimental conditions, including enzyme activity, binding characteristics, substrate specificity, and product analysis. In the course of our study, we encountered four types of distinct enzymatic hydrolysis modes denoted by substrate specificity and hydrolysis product formation: (i) exo-mode cellobiohydrolases (CBH), (ii) endo-mode cellulases with no specific hydrolysis pattern, endoglucanases (EG), (iii) processive endoglucanases with cellotetraose as intermediate product (pEG4), and (iv) processive endoglucanases with cellobiose as the main product (pEG2). These modes are shown on amorphous cellulose and on model cello-oligosaccharides (with degree of polymerization DP 3 to 6). Artificial mini-cellulosomes carrying combinations of cellulases showed their highest activity when all four endoglucanase-groups were incorporated into a single complex. Such a modeled nonavalent complex (n = 9 enzymes bound to the recombinant scaffolding protein CipA) reached half of the activity of the native cellulosome. Comparative analysis of the protein architecture and structure revealed characteristics that play a role in product formation and enzyme processivity. CONCLUSIONS The identification of a new endoglucanase type expands the list of known cellulase functions present in the cellulosome. Our study shows that the variety of processivities in the enzyme complex is a key enabler of its high cellulolytic efficiency. The observed synergistic effect may pave the way for a better understanding of the enzymatic interactions and the design of more active lignocellulose-degrading cellulase cocktails in the future.
Collapse
Affiliation(s)
- Benedikt Leis
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Claudia Held
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Fabian Bergkemper
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Katharina Dennemarck
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Robert Steinbauer
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Alarich Reiter
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Matthias Mechelke
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Matthias Moerch
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Sigrid Graubner
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang Liebl
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang H. Schwarz
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Vladimir V. Zverlov
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 2, Moscow, 123182 Russia
| |
Collapse
|
16
|
Enzymatic diversity of the Clostridium thermocellum cellulosome is crucial for the degradation of crystalline cellulose and plant biomass. Sci Rep 2016; 6:35709. [PMID: 27759119 PMCID: PMC5069625 DOI: 10.1038/srep35709] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/03/2016] [Indexed: 01/18/2023] Open
Abstract
The cellulosome is a supramolecular multienzyme complex comprised of a wide variety of polysaccharide-degrading enzymes and scaffold proteins. The cellulosomal enzymes that bind to the scaffold proteins synergistically degrade crystalline cellulose. Here, we report in vitro reconstitution of the Clostridium thermocellum cellulosome from 40 cellulosomal components and the full-length scaffoldin protein that binds to nine enzyme molecules. These components were each synthesized using a wheat germ cell-free protein synthesis system and purified. Cellulosome complexes were reconstituted from 3, 12, 30, and 40 components based on their contents in the native cellulosome. The activity of the enzyme-saturated complex indicated that greater enzymatic variety generated more synergy for the degradation of crystalline cellulose and delignified rice straw. Surprisingly, a less complete enzyme complex displaying fewer than nine enzyme molecules was more efficient for the degradation of delignified rice straw than the enzyme-saturated complex, despite the fact that the enzyme-saturated complex exhibited maximum synergy for the degradation of crystalline cellulose. These results suggest that greater enzymatic diversity of the cellulosome is crucial for the degradation of crystalline cellulose and plant biomass, and that efficient degradation of different substrates by the cellulosome requires not only a different enzymatic composition, but also different cellulosome structures.
Collapse
|
17
|
Moraïs S, Ben David Y, Bensoussan L, Duncan SH, Koropatkin NM, Martens EC, Flint HJ, Bayer EA. Enzymatic profiling of cellulosomal enzymes from the human gut bacterium, Ruminococcus champanellensis, reveals a fine-tuned system for cohesin-dockerin recognition. Environ Microbiol 2016; 18:542-56. [PMID: 26347002 DOI: 10.1111/1462-2920.13047] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 12/16/2023]
Abstract
Ruminococcus champanellensis is considered a keystone species in the human gut that degrades microcrystalline cellulose efficiently and contains the genetic elements necessary for cellulosome production. The basic elements of its cellulosome architecture, mainly cohesin and dockerin modules from scaffoldins and enzyme-borne dockerins, have been characterized recently. In this study, we cloned, expressed and characterized all of the glycoside hydrolases that contain a dockerin module. Among the 25 enzymes, 10 cellulases, 4 xylanases, 3 mannanases, 2 xyloglucanases, 2 arabinofuranosidases, 2 arabinanases and one β-glucanase were assessed for their comparative enzymatic activity on their respective substrates. The dockerin specificities of the enzymes were examined by ELISA, and 80 positives out of 525 possible interactions were detected. Our analysis reveals a fine-tuned system for cohesin-dockerin specificity and the importance of diversity among the cohesin-dockerin sequences. Our results imply that cohesin-dockerin pairs are not necessarily assembled at random among the same specificity types, as generally believed for other cellulosome-producing bacteria, but reveal a more organized cellulosome architecture. Moreover, our results highlight the importance of the cellulosome paradigm for cellulose and hemicellulose degradation by R. champanellensis in the human gut.
Collapse
Affiliation(s)
- Sarah Moraïs
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Yonit Ben David
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Lizi Bensoussan
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Sylvia H Duncan
- Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Harry J Flint
- Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - Edward A Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
18
|
Deng K, Takasuka TE, Bianchetti CM, Bergeman LF, Adams PD, Northen TR, Fox BG. Use of Nanostructure-Initiator Mass Spectrometry to Deduce Selectivity of Reaction in Glycoside Hydrolases. Front Bioeng Biotechnol 2015; 3:165. [PMID: 26579511 PMCID: PMC4621489 DOI: 10.3389/fbioe.2015.00165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/02/2015] [Indexed: 12/20/2022] Open
Abstract
Chemically synthesized nanostructure-initiator mass spectrometry (NIMS) probes derivatized with tetrasaccharides were used to study the reactivity of representative Clostridium thermocellum β-glucosidase, endoglucanases, and cellobiohydrolase. Diagnostic patterns for reactions of these different classes of enzymes were observed. Results show sequential removal of glucose by the β-glucosidase and a progressive increase in specificity of reaction from endoglucanases to cellobiohydrolase. Time-dependent reactions of these polysaccharide-selective enzymes were modeled by numerical integration, which provides a quantitative basis to make functional distinctions among a continuum of naturally evolved catalytic properties. Consequently, our method, which combines automated protein translation with high-sensitivity and time-dependent detection of multiple products, provides a new approach to annotate glycoside hydrolase phylogenetic trees with functional measurements.
Collapse
Affiliation(s)
- Kai Deng
- US Department of Energy Joint BioEnergy Institute , Emeryville, CA , USA ; Sandia National Laboratories , Livermore, CA , USA
| | - Taichi E Takasuka
- US Department of Energy Great Lakes Bioenergy Research Center , Madison, WI , USA
| | - Christopher M Bianchetti
- US Department of Energy Great Lakes Bioenergy Research Center , Madison, WI , USA ; Department of Chemistry, University of Wisconsin-Oshkosh , Oshkosh, WI , USA
| | - Lai F Bergeman
- US Department of Energy Great Lakes Bioenergy Research Center , Madison, WI , USA
| | - Paul D Adams
- US Department of Energy Joint BioEnergy Institute , Emeryville, CA , USA ; Lawrence Berkeley National Laboratory , Berkeley, CA , USA ; Department of Bioengineering, University of California Berkeley , Berkeley, CA , USA
| | - Trent R Northen
- US Department of Energy Joint BioEnergy Institute , Emeryville, CA , USA ; Lawrence Berkeley National Laboratory , Berkeley, CA , USA
| | - Brian G Fox
- US Department of Energy Great Lakes Bioenergy Research Center , Madison, WI , USA ; Department of Biochemistry, University of Wisconsin-Madison , Madison, WI , USA
| |
Collapse
|