1
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Moraïs S, Winkler S, Zorea A, Levin L, Nagies FSP, Kapust N, Lamed E, Artan-Furman A, Bolam DN, Yadav MP, Bayer EA, Martin WF, Mizrahi I. Cryptic diversity of cellulose-degrading gut bacteria in industrialized humans. Science 2024; 383:eadj9223. [PMID: 38484069 PMCID: PMC7615765 DOI: 10.1126/science.adj9223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 02/08/2024] [Indexed: 03/19/2024]
Abstract
Humans, like all mammals, depend on the gut microbiome for digestion of cellulose, the main component of plant fiber. However, evidence for cellulose fermentation in the human gut is scarce. We have identified ruminococcal species in the gut microbiota of human populations that assemble functional multienzymatic cellulosome structures capable of degrading plant cell wall polysaccharides. One of these species, which is strongly associated with humans, likely originated in the ruminant gut and was subsequently transferred to the human gut, potentially during domestication where it underwent diversification and diet-related adaptation through the acquisition of genes from other gut microbes. Collectively, these species are abundant and widespread among ancient humans, hunter-gatherers, and rural populations but are rare in populations from industrialized societies thus indicating potential disappearance in response to the westernized lifestyle.
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Affiliation(s)
- Sarah Moraïs
- National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
- The Goldman Sonnenfeldt School of Sustainability and Climate Change, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Sarah Winkler
- National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
- The Goldman Sonnenfeldt School of Sustainability and Climate Change, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Alvah Zorea
- National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
- The Goldman Sonnenfeldt School of Sustainability and Climate Change, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Liron Levin
- Bioinformatics Core Facility, llse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Falk S. P. Nagies
- Department of Biology, Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, D-40225, Düsseldorf, Germany
| | - Nils Kapust
- Department of Biology, Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, D-40225, Düsseldorf, Germany
| | - Eva Lamed
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001 Israel
| | - Avital Artan-Furman
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001 Israel
| | - David N. Bolam
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Madhav P. Yadav
- US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA
| | - Edward A. Bayer
- National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001 Israel
| | - William F. Martin
- Department of Biology, Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, D-40225, Düsseldorf, Germany
| | - Itzhak Mizrahi
- National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
- The Goldman Sonnenfeldt School of Sustainability and Climate Change, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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2
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Zajki-Zechmeister K, Eibinger M, Kaira GS, Nidetzky B. Mechanochemical Coupling of Catalysis and Motion in a Cellulose-Degrading Multienzyme Nanomachine. ACS Catal 2024; 14:2656-2663. [PMID: 38384941 PMCID: PMC10877591 DOI: 10.1021/acscatal.3c05653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/13/2024] [Accepted: 01/24/2024] [Indexed: 02/23/2024]
Abstract
The cellulosome is a megadalton-size protein complex that functions as a biological nanomachine of cellulosic fiber degradation. We show that the cellulosome behaves as a Brownian ratchet that rectifies protein motions on the cellulose surface into a propulsion mechanism by coupling to the hydrolysis of cellulose chains. Movement on cellulose fibrils is unidirectional and results from "macromolecular crawl" composed of dynamic switches between elongated and compact spatial arrangements of enzyme subunits. Deletion of the main exocellulase Cel48S eliminates conformational bias for aligning the subunits to the long fibril axis, which we reveal as crucial for optimum coupling between directional movement and substrate degradation. Implications of the cellulosome acting as a mechanochemical motor suggest a distinct mechanism of enzymatic machinery in the deconstruction of cellulose assemblies.
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Affiliation(s)
- Krisztina Zajki-Zechmeister
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, Graz 8010, Austria
| | - Manuel Eibinger
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, Graz 8010, Austria
| | - Gaurav Singh Kaira
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, Graz 8010, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, Graz 8010, Austria
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, Graz 8010, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, Graz 8010, Austria
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3
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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.
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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.
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Moraïs S, Stern J, Artzi L, Fontes CMGA, Bayer EA, Mizrahi I. Carbohydrate Depolymerization by Intricate Cellulosomal Systems. Methods Mol Biol 2023; 2657:53-77. [PMID: 37149522 DOI: 10.1007/978-1-0716-3151-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cellulosomes are multi-enzymatic nanomachines that have been fine-tuned through evolution to efficiently deconstruct plant biomass. Integration of cellulosomal components occurs via highly ordered protein-protein interactions between the various enzyme-borne dockerin modules and the multiple copies of the cohesin modules located on the scaffoldin subunit. Recently, designer cellulosome technology was established to provide insights into the architectural role of catalytic (enzymatic) and structural (scaffoldin) cellulosomal constituents for the efficient degradation of plant cell wall polysaccharides. Owing to advances in genomics and proteomics, highly structured cellulosome complexes have recently been unraveled, and the information gained has inspired the development of designer-cellulosome technology to new levels of complex organization. These higher-order designer cellulosomes have in turn fostered our capacity to enhance the catalytic potential of artificial cellulolytic complexes. In this chapter, methods to produce and employ such intricate cellulosomal complexes are reported.
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Affiliation(s)
- Sarah Moraïs
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Lior Artzi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | | | - Edward A Bayer
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.
| | - Itzhak Mizrahi
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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5
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Zajki-Zechmeister K, Kaira GS, Eibinger M, Seelich K, Nidetzky B. Processive Enzymes Kept on a Leash: How Cellulase Activity in Multienzyme Complexes Directs Nanoscale Deconstruction of Cellulose. ACS Catal 2021; 11:13530-13542. [PMID: 34777910 PMCID: PMC8576811 DOI: 10.1021/acscatal.1c03465] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/11/2021] [Indexed: 12/15/2022]
Abstract
Biological deconstruction of polymer materials gains efficiency from the spatiotemporally coordinated action of enzymes with synergetic function in polymer chain depolymerization. To perpetuate enzyme synergy on a solid substrate undergoing deconstruction, the overall attack must alternate between focusing the individual enzymes locally and dissipating them again to other surface sites. Natural cellulases working as multienzyme complexes assembled on a scaffold protein (the cellulosome) maximize the effect of local concentration yet restrain the dispersion of individual enzymes. Here, with evidence from real-time atomic force microscopy to track nanoscale deconstruction of single cellulose fibers, we show that the cellulosome forces the fiber degradation into the transversal direction, to produce smaller fragments from multiple local attacks ("cuts"). Noncomplexed enzymes, as in fungal cellulases or obtained by dissociating the cellulosome, release the confining force so that fiber degradation proceeds laterally, observed as directed ablation of surface fibrils and leading to whole fiber "thinning". Processive cellulases that are enabled to freely disperse evoke the lateral degradation and determine its efficiency. Our results suggest that among natural cellulases, the dispersed enzymes are more generally and globally effective in depolymerization, while the cellulosome represents a specialized, fiber-fragmenting machinery.
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Affiliation(s)
- Krisztina Zajki-Zechmeister
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Gaurav Singh Kaira
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
| | - Manuel Eibinger
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Klara Seelich
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
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6
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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.
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7
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Li J, Liu F, Yu H, Li Y, Zhou S, Ai Y, Zhou X, Wang Y, Wang L, Peng L, Wang Y. Diverse Banana Pseudostems and Rachis Are Distinctive for Edible Carbohydrates and Lignocellulose Saccharification towards High Bioethanol Production under Chemical and Liquid Hot Water Pretreatments. Molecules 2021; 26:molecules26133870. [PMID: 34202856 PMCID: PMC8270323 DOI: 10.3390/molecules26133870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/31/2021] [Accepted: 06/15/2021] [Indexed: 11/20/2022] Open
Abstract
Banana is a major fruit crop throughout the world with abundant lignocellulose in the pseudostem and rachis residues for biofuel production. In this study, we collected a total of 11 pseudostems and rachis samples that were originally derived from different genetic types and ecological locations of banana crops and then examined largely varied edible carbohydrates (soluble sugars, starch) and lignocellulose compositions. By performing chemical (H2SO4, NaOH) and liquid hot water (LHW) pretreatments, we also found a remarkable variation in biomass enzymatic saccharification and bioethanol production among all banana samples examined. Consequently, this study identified a desirable banana (Refen1, subgroup Pisang Awak) crop containing large amounts of edible carbohydrates and completely digestible lignocellulose, which could be combined to achieve the highest bioethanol yields of 31–38% (% dry matter), compared with previously reported ones in other bioenergy crops. Chemical analysis further indicated that the cellulose CrI and lignin G-monomer should be two major recalcitrant factors affecting biomass enzymatic saccharification in banana pseudostems and rachis. Therefore, this study not only examined rich edible carbohydrates for food in the banana pseudostems but also detected digestible lignocellulose for bioethanol production in rachis tissue, providing a strategy applicable for genetic breeding and biomass processing in banana crops.
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Affiliation(s)
- Jingyang Li
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
- Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou 570102, China
| | - Fei Liu
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Hua Yu
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Yuqi Li
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Shiguang Zhou
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Yuanhang Ai
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Xinyu Zhou
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Youmei Wang
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Lingqiang Wang
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- State Key Laboratory for Conservation & Utilization of Subtropical Agro-Bioresources, College of Agriculture, Guangxi University, Nanning 530000, China
| | - Liangcai Peng
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
| | - Yanting Wang
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; (J.L.); (F.L.); (H.Y.); (S.Z.); (Y.A.); (X.Z.); (Y.W.); (L.W.); (L.P.)
- Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;
- Correspondence:
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8
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Vera AM, Galera-Prat A, Wojciechowski M, Różycki B, Laurents DV, Carrión-Vázquez M, Cieplak M, Tinnefeld P. Cohesin-dockerin code in cellulosomal dual binding modes and its allosteric regulation by proline isomerization. Structure 2021; 29:587-597.e8. [PMID: 33561387 DOI: 10.1016/j.str.2021.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/25/2020] [Accepted: 01/11/2021] [Indexed: 12/20/2022]
Abstract
Cellulose is the most abundant organic molecule on Earth and represents a renewable and practically everlasting feedstock for the production of biofuels and chemicals. Self-assembled owing to the high-affinity cohesin-dockerin interaction, cellulosomes are huge multi-enzyme complexes with unmatched efficiency in the degradation of recalcitrant lignocellulosic substrates. The recruitment of diverse dockerin-borne enzymes into a multicohesin protein scaffold dictates the three-dimensional layout of the complex, and interestingly two alternative binding modes have been proposed. Using single-molecule fluorescence resonance energy transfer and molecular simulations on a range of cohesin-dockerin pairs, we directly detect varying distributions between these binding modes that follow a built-in cohesin-dockerin code. Surprisingly, we uncover a prolyl isomerase-modulated allosteric control mechanism, mediated by the isomerization state of a single proline residue, which regulates the distribution and kinetics of binding modes. Overall, our data provide a novel mechanistic understanding of the structural plasticity and dynamics of cellulosomes.
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Affiliation(s)
- Andrés Manuel Vera
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 Haus E, 81377 München, Germany.
| | - Albert Galera-Prat
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland
| | - Michał Wojciechowski
- Institute of Physics, Polish Academy of Sciences, Al. Lotników, 32/46, 02-668 Warsaw, Poland
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotników, 32/46, 02-668 Warsaw, Poland
| | - Douglas V Laurents
- Instituto de Química Física "Rocasolano", CSIC, C/ Serrano 119, 28006 Madrid, Spain
| | | | - Marek Cieplak
- Institute of Physics, Polish Academy of Sciences, Al. Lotników, 32/46, 02-668 Warsaw, Poland
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 Haus E, 81377 München, Germany
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9
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Research progress and the biotechnological applications of multienzyme complex. Appl Microbiol Biotechnol 2021; 105:1759-1777. [PMID: 33564922 DOI: 10.1007/s00253-021-11121-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/07/2021] [Accepted: 01/16/2021] [Indexed: 11/26/2022]
Abstract
The multienzyme complex system has become a research focus in synthetic biology due to its highly efficient overall catalytic ability and has been applied to various fields. Multienzyme complexes are formed by cascading complexes, which are multiple functionally related enzymes that continuously and efficiently catalyze the production of substrates. Compared with current mainstream microbial cell catalytic systems, in vitro multienzyme molecular machines have many advantages, such as fewer side reactions, a high product yield, a fast reaction speed, easy product separation, a tolerable toxic environment, and robust system operability, showing increasing competitiveness in the field of biomanufacturing. In this review, the research progress of multienzyme complexes in nature and multienzyme cascades in vivo or in vitro will be introduced, and the discovered enzyme cascades concerning scaffolding proteins will also be discussed. This review is expected to provide a more theoretical basis for the modification of multienzyme complexes and broaden their application in the field of synthetic biology. KEY POINTS: • The cascade reactions of some natural multienzyme complexes are reviewed. • The main approaches of constructing artificial multienzyme complexes are summarized. • The structure and application of cellulosomes are discussed and prospected.
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10
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Bacterial valorization of pulp and paper industry process streams and waste. Appl Microbiol Biotechnol 2021; 105:1345-1363. [PMID: 33481067 DOI: 10.1007/s00253-021-11107-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/28/2020] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
The pulp and paper industry is a major source of lignocellulose-containing streams. The components of lignocellulose material are lignin, hemicellulose, and cellulose that may be hydrolyzed into their smaller components and used as feedstocks for valorization efforts. Much of this material is contained in underutilized streams and waste products, such as black liquor, pulp and paper sludge, and wastewater. Bacterial fermentation strategies have suitable potential to upgrade lignocellulosic biomass contained in these streams to value-added chemicals. Bacterial conversion allows for a sustainable and economically feasible approach to valorizing these streams, which can bolster and expand applications of the pulp and paper industry. This review discusses the composition of pulp and paper streams, bacterial isolates from process streams that can be used for lignocellulose biotransformations, and technological approaches for improving valorization efforts. KEY POINTS: • Reviews the conversion of pulp and paper industry waste by bacterial isolates. • Metabolic pathways for the breakdown of lignocellulose components. • Methods for isolating bacteria, determining value-added products, and increasing product yields.
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11
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Abstract
Cellulosomes are elaborate multienzyme complexes capable of efficiently deconstructing lignocellulosic substrates, produced by cellulolytic anaerobic microorganisms, colonizing a large variety of ecological niches. These macromolecular structures have a modular architecture and are composed of two main elements: the cohesin-bearing scaffoldins, which are non-catalytic structural proteins, and the various dockerin-bearing enzymes that tenaciously bind to the scaffoldins. Cellulosome assembly is mediated by strong and highly specific interactions between the cohesin modules, present in the scaffoldins, and the dockerin modules, present in the catalytic units. Cellulosomal architecture and composition varies between species and can even change within the same organism. These differences seem to be largely influenced by external factors, including the nature of the available carbon-source. Even though cellulosome producing organisms are relatively few, the development of new genomic and proteomic technologies has allowed the identification of cellulosomal components in many archea, bacteria and even some primitive eukaryotes. This reflects the importance of this cellulolytic strategy and suggests that cohesin-dockerin interactions could be involved in other non-cellulolytic processes. Due to their building-block nature and highly cellulolytic capabilities, cellulosomes hold many potential biotechnological applications, such as the conversion of lignocellulosic biomass in the production of biofuels or the development of affinity based technologies.
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Affiliation(s)
- Victor D Alves
- CIISA, Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal
| | - Carlos M G A Fontes
- CIISA, Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal
| | - Pedro Bule
- CIISA, Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal.
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12
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Vanderstraeten J, Briers Y. Synthetic protein scaffolds for the colocalisation of co-acting enzymes. Biotechnol Adv 2020; 44:107627. [DOI: 10.1016/j.biotechadv.2020.107627] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/17/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023]
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13
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Ben‐David Y, Moraïs S, Bayer EA, Mizrahi I. Rapid adaptation for fibre degradation by changes in plasmid stoichiometry within Lactobacillus plantarum at the synthetic community level. Microb Biotechnol 2020; 13:1748-1764. [PMID: 32639625 PMCID: PMC7533337 DOI: 10.1111/1751-7915.13584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/11/2020] [Accepted: 04/12/2020] [Indexed: 12/19/2022] Open
Abstract
The multi-enzyme cellulosome complex can mediate the valorization of lignocellulosic biomass into soluble sugars that can serve in the production of biofuels and valuable products. A potent bacterial chassis for the production of active cellulosomes displayed on the cell surface is the bacterium Lactobacillus plantarum, a lactic acid bacterium used in many applications. Here, we developed a methodological pipeline to produce improved designer cellulosomes, using a cell-consortium approach, whereby the different components self-assemble on the surface of L. plantarum. The pipeline served as a vehicle to select and optimize the secretion efficiency of potent designer cellulosome enzyme components, to screen for the most efficient enzymatic combinations and to assess attempts to grow the engineered bacterial cells on wheat straw as a sole carbon source. Using this strategy, we were able to improve the secretion efficiency of the selected enzymes and to secrete a fully functional high-molecular-weight scaffoldin component. The adaptive laboratory process served to increase significantly the enzymatic activity of the most efficient cell consortium. Internal plasmid re-arrangement towards a higher enzymatic performance attested for the suitability of the approach, which suggests that this strategy represents an efficient way for microbes to adapt to changing conditions.
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Affiliation(s)
- Yonit Ben‐David
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovot7610001Israel
| | - Sarah Moraïs
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovot7610001Israel
- Department of Life SciencesNational Institute for Biotechnology in the NegevBen‐Gurion University of the NegevBeer‐Sheva8499000Israel
| | - Edward A. Bayer
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovot7610001Israel
| | - Itzhak Mizrahi
- Department of Life SciencesNational Institute for Biotechnology in the NegevBen‐Gurion University of the NegevBeer‐Sheva8499000Israel
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14
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Galera-Prat A, Vera AM, Moraïs S, Vazana Y, Bayer EA, Carrión-Vázquez M. Impact of scaffoldin mechanostability on cellulosomal activity. Biomater Sci 2020; 8:3601-3610. [PMID: 32232253 DOI: 10.1039/c9bm02052g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lignocellulose is the most abundant renewable carbon source in the biosphere. However, the main bottleneck in its conversion to produce second generation biofuels is the saccharification step: the hydrolysis of lignocellulosic material into soluble fermentable sugars. Some anaerobic bacteria have developed an extracellular multi-enzyme complex called the cellulosome that efficiently degrades cellulosic substrates. Cellulosome complexes rely on enzyme-integrating scaffoldins that are large non-catalytic scaffolding proteins comprising several cohesin modules and additional functional modules that mediate the anchoring of the complex to the cell surface and the specific binding to its cellulosic substrate. It was proposed that mechanical forces may affect the cohesins positioned between the cell- and cellulose-anchoring points in the so-called connecting region. Consequently, the mechanical resistance of cohesins within the scaffoldin is of great importance, both to understand cellulosome function and as a parameter of industrial interest, to better mimic natural complexes through the use of the established designer cellulosome technology. Here we study how the mechanical stability of cohesins in a scaffoldin affects the enzymatic activity of a cellulosome. We found that when a cohesin of low mechanical stability is positioned in the connecting region of a scaffoldin, the activity of the resulting cellulosome is reduced as opposed to a cohesin of higher mechanical stability. This observation directly relates mechanical stability of the scaffoldin-borne cohesins to cellulosome activity and provides a rationale for the design of artificial cellulosomes for industrial applications, by incorporating mechanical stability as a new industrial parameter in the biotechnology toolbox.
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Affiliation(s)
- Albert Galera-Prat
- Instituto Cajal, Department of Molecular, Cellular and Developmental Neurobiology. IC-CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain.
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15
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Eibinger M, Ganner T, Plank H, Nidetzky B. A Biological Nanomachine at Work: Watching the Cellulosome Degrade Crystalline Cellulose. ACS CENTRAL SCIENCE 2020; 6:739-746. [PMID: 32490190 PMCID: PMC7256933 DOI: 10.1021/acscentsci.0c00050] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Indexed: 05/14/2023]
Abstract
The cellulosome is a supramolecular multienzymatic protein complex that functions as a biological nanomachine of cellulosic biomass degradation. How the megadalton-size cellulosome adapts to a solid substrate is central to its mechanism of action and is also key for its efficient use in bioconversion applications. We report time-lapse visualization of crystalline cellulose degradation by individual cellulosomes from Clostridium thermocellum by atomic force microscopy. Upon binding to cellulose, the cellulosomes switch to elongated, even filamentous shapes and morph these dynamically at below 1 min time scale according to requirements of the substrate surface under attack. Compared with noncomplexed cellulases that peel off material while sliding along crystalline cellulose surfaces, the cellulosomes remain bound locally for minutes and remove the material lying underneath. The consequent roughening up of the surface leads to an efficient deconstruction of cellulose nanocrystals both from the ends and through fissions within. Distinct modes of cellulose nanocrystal deconstruction by nature's major cellulase systems are thus revealed.
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Affiliation(s)
- Manuel Eibinger
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Thomas Ganner
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
| | - Harald Plank
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
- Graz
Centre of Electron Microscopy, Steyrergasse 17, A-8010 Graz, Austria
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
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16
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Kahn A, Moraïs S, Chung D, Sarai NS, Hengge NN, Kahn A, Himmel ME, Bayer EA, Bomble YJ. Glycosylation of hyperthermostable designer cellulosome components yields enhanced stability and cellulose hydrolysis. FEBS J 2020; 287:4370-4388. [DOI: 10.1111/febs.15251] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/06/2020] [Accepted: 02/14/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Amaranta Kahn
- Department of Biomolecular Sciences The Weizmann Institute of Science Rehovot Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences The Weizmann Institute of Science Rehovot Israel
- Faculty of Natural Sciences Ben‐Gurion University of the Negev Beer‐Sheva Israel
| | - Daehwan Chung
- Biosciences Center National Renewable Energy Laboratory Golden CO USA
| | - Nicholas S. Sarai
- Biosciences Center National Renewable Energy Laboratory Golden CO USA
| | - Neal N. Hengge
- Biosciences Center National Renewable Energy Laboratory Golden CO USA
| | - Audrey Kahn
- Department of Biomolecular Sciences The Weizmann Institute of Science Rehovot Israel
| | - Michael E. Himmel
- Biosciences Center National Renewable Energy Laboratory Golden CO USA
| | - Edward A. Bayer
- Department of Biomolecular Sciences The Weizmann Institute of Science Rehovot Israel
| | - Yannick J. Bomble
- Biosciences Center National Renewable Energy Laboratory Golden CO USA
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17
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Anandharaj M, Lin YJ, Rani RP, Nadendla EK, Ho MC, Huang CC, Cheng JF, Chang JJ, Li WH. Constructing a yeast to express the largest cellulosome complex on the cell surface. Proc Natl Acad Sci U S A 2020; 117:2385-2394. [PMID: 31953261 PMCID: PMC7007581 DOI: 10.1073/pnas.1916529117] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Cellulosomes, which are multienzyme complexes from anaerobic bacteria, are considered nature's finest cellulolytic machinery. Thus, constructing a cellulosome in an industrial yeast has long been a goal pursued by scientists. However, it remains highly challenging due to the size and complexity of cellulosomal genes. Here, we overcame the difficulties by synthesizing the Clostridium thermocellum scaffoldin gene (CipA) and the anchoring protein gene (OlpB) using advanced synthetic biology techniques. The engineered Kluyveromyces marxianus, a probiotic yeast, secreted a mixture of dockerin-fused fungal cellulases, including an endoglucanase (TrEgIII), exoglucanase (CBHII), β-glucosidase (NpaBGS), and cellulase boosters (TaLPMO and MtCDH). The confocal microscopy results confirmed the cell-surface display of OlpB-ScGPI and fluorescence-activated cell sorting analysis results revealed that almost 81% of yeast cells displayed OlpB-ScGPI. We have also demonstrated the cellulosome complex formation using purified and crude cellulosomal proteins. Native polyacrylamide gel electrophoresis and mass spectrometric analysis further confirmed the cellulosome complex formation. Our engineered cellulosome can accommodate up to 63 enzymes, whereas the largest engineered cellulosome reported thus far could accommodate only 12 enzymes and was expressed by a plasmid instead of chromosomal integration. Interestingly, CipA 2B9C (with two cellulose binding modules, CBM) released significantly higher quantities of reducing sugars compared with other CipA variants, thus confirming the importance of cohesin numbers and CBM domain on cellulosome complex. The engineered yeast host efficiently degraded cellulosic substrates and released 3.09 g/L and 8.61 g/L of ethanol from avicel and phosphoric acid-swollen cellulose, respectively, which is higher than any previously constructed yeast cellulosome.
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Affiliation(s)
- Marimuthu Anandharaj
- Biodiversity Research Center, Academia Sinica, 11529 Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, 11529 Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, 40227 Taichung, Taiwan
| | - Yu-Ju Lin
- Biodiversity Research Center, Academia Sinica, 11529 Taipei, Taiwan
| | | | | | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, 11529 Taipei, Taiwan
| | - Chieh-Chen Huang
- Department of Life Sciences, National Chung Hsing University, 40227 Taichung, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, 40227 Taichung, Taiwan
| | - Jan-Fang Cheng
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA 94598
| | - Jui-Jen Chang
- Department of Medical Research, China Medical University Hospital, China Medical University, 402 Taichung, Taiwan;
| | - Wen-Hsiung Li
- Biodiversity Research Center, Academia Sinica, 11529 Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, 11529 Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, 40227 Taichung, Taiwan
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637
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18
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Xu C, Zhang J, Zhang Y, Guo Y, Xu H, Liang C, Wang Z, Xu J. Lignin prepared from different alkaline pretreated sugarcane bagasse and its effect on enzymatic hydrolysis. Int J Biol Macromol 2019; 141:484-492. [DOI: 10.1016/j.ijbiomac.2019.08.263] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/23/2019] [Accepted: 08/30/2019] [Indexed: 01/06/2023]
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19
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The Cellulosome Paradigm in An Extreme Alkaline Environment. Microorganisms 2019; 7:microorganisms7090347. [PMID: 31547347 PMCID: PMC6780208 DOI: 10.3390/microorganisms7090347] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/01/2019] [Accepted: 09/10/2019] [Indexed: 11/19/2022] Open
Abstract
Rapid decomposition of plant biomass in soda lakes is associated with microbial activity of anaerobic cellulose-degrading communities. The alkaliphilic bacterium, Clostridium alkalicellulosi, is the single known isolate from a soda lake that demonstrates cellulolytic activity. This microorganism secretes cellulolytic enzymes that degrade cellulose under anaerobic and alkaliphilic conditions. A previous study indicated that the protein fraction of cellulose-grown cultures showed similarities in composition and size to known components of the archetypical cellulosome Clostridium thermocellum. Bioinformatic analysis of the C. alkalicellulosi draft genome sequence revealed 44 cohesins, organized into 22 different scaffoldins, and 142 dockerin-containing proteins. The modular organization of the scaffoldins shared similarities to those of C. thermocellum and Acetivibrio cellulolyticus, whereas some exhibited unconventional arrangements containing peptidases and oxidative enzymes. The binding interactions among cohesins and dockerins assessed by ELISA, revealed a complex network of cellulosome assemblies and suggested both cell-associated and cell-free systems. Based on these interactions, C. alkalicellulosi cellulosomal systems have the genetic potential to create elaborate complexes, which could integrate up to 105 enzymatic subunits. The alkalistable C. alkalicellulosi cellulosomal systems and their enzymes would be amenable to biotechnological processes, such as treatment of lignocellulosic biomass following prior alkaline pretreatment.
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20
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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
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21
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Wang Y, Leng L, Islam MK, Liu F, Lin CSK, Leu SY. Substrate-Related Factors Affecting Cellulosome-Induced Hydrolysis for Lignocellulose Valorization. Int J Mol Sci 2019; 20:ijms20133354. [PMID: 31288425 PMCID: PMC6651384 DOI: 10.3390/ijms20133354] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/30/2019] [Accepted: 07/03/2019] [Indexed: 11/22/2022] Open
Abstract
Cellulosomes are an extracellular supramolecular multienzyme complex that can efficiently degrade cellulose and hemicelluloses in plant cell walls. The structural and unique subunit arrangement of cellulosomes can promote its adhesion to the insoluble substrates, thus providing individual microbial cells with a direct competence in the utilization of cellulosic biomass. Significant progress has been achieved in revealing the structures and functions of cellulosomes, but a knowledge gap still exists in understanding the interaction between cellulosome and lignocellulosic substrate for those derived from biorefinery pretreatment of agricultural crops. The cellulosomic saccharification of lignocellulose is affected by various substrate-related physical and chemical factors, including native (untreated) wood lignin content, the extent of lignin and xylan removal by pretreatment, lignin structure, substrate size, and of course substrate pore surface area or substrate accessibility to cellulose. Herein, we summarize the cellulosome structure, substrate-related factors, and regulatory mechanisms in the host cells. We discuss the latest advances in specific strategies of cellulosome-induced hydrolysis, which can function in the reaction kinetics and the overall progress of biorefineries based on lignocellulosic feedstocks.
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Affiliation(s)
- Ying Wang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ling Leng
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Md Khairul Islam
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Fanghua Liu
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
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Laluce C, Igbojionu LI, Silva JL, Ribeiro CA. Statistical prediction of interactions between low concentrations of inhibitors on yeast cells responses added to the SD-medium at low pH values. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:114. [PMID: 31086566 PMCID: PMC6507146 DOI: 10.1186/s13068-019-1453-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND In the present work, the main inhibitors of the yeast cells (vanillin, furfural, formic, and levulinic acid) were generated by pretreatments or hydrolysis (sulfuric acid or enzymes) to convert reducing sugars into ethanol. Inhibitors were added at increasing concentrations to the SD-medium containing yeast extract while negative effects on yeast cells were observed. Statistical analyses were applied to predict and interpret results related to biomass production. RESULTS Inhibitors affected productivities and yields of biomass and ethanol when added to SD-medium. Based on the 23 full-central-composite design, "predicted" and "observed" values of ethanol and biomass were obtained in presence of the major inhibitors, which were acetic acid, formic acid, and levulinic acids. Increases in biomass and ethanol production are described in the Response surface graphs (RSM graphs) that resulted from multiple interactions between inhibitors. Positive interactions between the inhibitors occurred at low concentrations and pH values. The results were experimentally validated. CONCLUSIONS Statistical analysis is an extremely useful tool for predicting data during process monitoring, while re-adjustments of conditions can be performed, whenever necessary. In addition, the development of new strains of yeast with high tolerance to biomass inhibitors will have a major impact on the production of second-generation ethanol. Increases in fermentation activity of the yeast Saccharomyces cerevisiae in a mixture containing low concentrations of inhibitors were observed.
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Affiliation(s)
- Cecilia Laluce
- Institute of Research in Bioenergy (IPBEN), Institute of Chemistry, São Paulo State University (UNESP), R. Prof. Francisco Degni, 55, Araraquara, SP CEP 14800-060 Brazil
| | - Longinus I. Igbojionu
- Institute of Research in Bioenergy (IPBEN), Institute of Chemistry, São Paulo State University (UNESP), R. Prof. Francisco Degni, 55, Araraquara, SP CEP 14800-060 Brazil
| | - José L. Silva
- Institute of Research in Bioenergy (IPBEN), Institute of Chemistry, São Paulo State University (UNESP), R. Prof. Francisco Degni, 55, Araraquara, SP CEP 14800-060 Brazil
| | - Clóvis A. Ribeiro
- Dept Analytical Chemistry, Institute of Chemistry, State University of São Paulo, Júlio de Mesquita Filho-UNESP, R. Professor Francisco Degni, 55, Araraquara, São Paulo CEP 14800-060 Brazil
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An engineered GH1 β-glucosidase displays enhanced glucose tolerance and increased sugar release from lignocellulosic materials. Sci Rep 2019; 9:4903. [PMID: 30894609 PMCID: PMC6426972 DOI: 10.1038/s41598-019-41300-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/26/2019] [Indexed: 11/08/2022] Open
Abstract
β-glucosidases play a critical role among the enzymes in enzymatic cocktails designed for plant biomass deconstruction. By catalysing the breakdown of β-1, 4-glycosidic linkages, β-glucosidases produce free fermentable glucose and alleviate the inhibition of other cellulases by cellobiose during saccharification. Despite this benefit, most characterised fungal β-glucosidases show weak activity at high glucose concentrations, limiting enzymatic hydrolysis of plant biomass in industrial settings. In this study, structural analyses combined with site-directed mutagenesis efficiently improved the functional properties of a GH1 β-glucosidase highly expressed by Trichoderma harzianum (ThBgl) under biomass degradation conditions. The tailored enzyme displayed high glucose tolerance levels, confirming that glucose tolerance can be achieved by the substitution of two amino acids that act as gatekeepers, changing active-site accessibility and preventing product inhibition. Furthermore, the enhanced efficiency of the engineered enzyme in terms of the amount of glucose released and ethanol yield was confirmed by saccharification and simultaneous saccharification and fermentation experiments using a wide range of plant biomass feedstocks. Our results not only experimentally confirm the structural basis of glucose tolerance in GH1 β-glucosidases but also demonstrate a strategy to improve technologies for bioethanol production based on enzymatic hydrolysis.
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24
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Ben-David Y, Morais S, Stern J, Mizrahi I, Bayer EA. Cell-surface display of designer cellulosomes by Lactobacillus plantarum. Methods Enzymol 2019; 617:241-263. [PMID: 30784404 DOI: 10.1016/bs.mie.2018.12.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cell-surface display of designer cellulosomes complexes has attracted increased interest in recent years. These engineered microorganisms can efficiently degrade lignocellulosic biomass that represents an abundant resource for conversion into fermentable sugars, suitable for production of biofuels. The designer cellulosome is an artificial enzymatic complex that mimics the architecture of the natural cellulosome and allows the control of the positions, type, and copy number of the cellulosomal enzymes within the complex. Lactobacillus plantarum is an attractive candidate for metabolic engineering of lignocellulosic biomass to biofuels, as its natural characteristics include high ethanol and acid tolerance and the ability to metabolize hexose sugars. In recent years, successful expression of a variety of designer cellulosomes on the cell surface of this bacterium has been demonstrated using the cell-consortium approach. This strategy minimized genomic interference on each strain upon genetic engineering, thereby maximizing the ability of each strain to grow, express, and secrete each enzyme. In addition, this strategy allows stoichiometric control of the cellulosome elements and facile exchange of the secreted proteins. A detailed procedure for display of designer cellulosomes on the cell surface of L. plantarum is described in this chapter.
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Affiliation(s)
- Yonit Ben-David
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Sarah Morais
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel; Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Itzhak Mizrahi
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.
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25
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Badhan A, Huang J, Wang Y, Abbott DW, Di Falco M, Tsang A, McAllister T. Saccharification efficiencies of multi-enzyme complexes produced by aerobic fungi. N Biotechnol 2018; 46:1-6. [PMID: 29803771 DOI: 10.1016/j.nbt.2018.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 11/16/2022]
Abstract
In the present study, we have characterized high molecular weight multi-enzyme complexes in two commercial enzymes produced by Trichoderma reesei (Spezyme CP) and Penicillium funiculosum (Accellerase XC). We successfully identified 146-1000 kDa complexes using Blue native polyacrylamide gel electrophoresis (BN-PAGE) to fractionate the protein profile in both preparations. Identified complexes dissociated into lower molecular weight constituents when loaded on SDS PAGE. Unfolding of the secondary structure of multi-enzyme complexes with trimethylamine (pH >10) suggested that they were not a result of unspecific protein aggregation. Cellulase (CMCase) profiles of extracts of BN-PAGE fractionated protein bands confirmed cellulase activity within the multi-enzyme complexes. A microassay was used to identify protein bands that promoted high levels of glucose release from barley straw. Those with high saccharification yield were subjected to LC-MS analysis to identify the principal enzymatic activities responsible. The results suggest that secretion of proteins by aerobic fungi leads to the formation of high molecular weight multi-enzyme complexes that display activity against carboxymethyl cellulose and barley straw.
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Affiliation(s)
- Ajay Badhan
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Jiangli Huang
- Institute of Biological Resources, Jiangxi Academy of Sciences, Nanchang, 330096, China
| | - Yuxi Wang
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - D Wade Abbott
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Marcos Di Falco
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, H4B 1R6, Canada
| | - Adrian Tsang
- Institute of Biological Resources, Jiangxi Academy of Sciences, Nanchang, 330096, China
| | - Tim McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada.
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Refactoring the upper sugar metabolism of Pseudomonas putida for co-utilization of cellobiose, xylose, and glucose. Metab Eng 2018; 48:94-108. [DOI: 10.1016/j.ymben.2018.05.019] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/15/2018] [Accepted: 05/31/2018] [Indexed: 01/02/2023]
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27
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Chen L, Ge X. Correlation Between Size and Activity Enhancement of Recombinantly Assembled Cellulosomes. Appl Biochem Biotechnol 2018; 186:937-948. [PMID: 29797297 DOI: 10.1007/s12010-018-2786-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/15/2018] [Indexed: 11/25/2022]
Abstract
As multienzyme complexes, cellulosomes hydrolyze cellulosic biomass with high efficiency, which is believed to be attributed to either one or both factors: (1) synergy among the catalytic and substrate-binding entities and (2) the large size of cellulosome complexes. Although the former factor has been extensively documented, the correlation between size and specific activity of cellulosomes is still elusive to date. In this study, primary and secondary scaffoldins with 1, 3, or 5 copies of type I/II cohesin domains were recombinantly synthesized and various cellulosomes carrying 1, 3, 5, 9, 15, or 25 molecules of cellulase mixtures of family 5, 9, and 48 glycoside hydrolases were assembled. In addition, the assembled complex was annexed to cellulose with the aid of a family 3a carbohydrate-binding module (CBM3a). Measuring cellulolytic hydrolysis activities of assembled cellulosomes on crystalline Avicel revealed that higher degree of cellulosome complexity resulted in more efficient cellulose hydrolysis with plateaued synergic effects after the cellulosome size reaches certain degree.
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Affiliation(s)
- Long Chen
- Department of Chemical and Environmental Engineering, University of California Riverside, 900 University Ave, Riverside, CA, 92512, USA
| | - Xin Ge
- Department of Chemical and Environmental Engineering, University of California Riverside, 900 University Ave, Riverside, CA, 92512, USA.
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28
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Bule P, Pires VMR, Alves VD, Carvalho AL, Prates JAM, Ferreira LMA, Smith SP, Gilbert HJ, Noach I, Bayer EA, Najmudin S, Fontes CMGA. Higher order scaffoldin assembly in Ruminococcus flavefaciens cellulosome is coordinated by a discrete cohesin-dockerin interaction. Sci Rep 2018; 8:6987. [PMID: 29725056 PMCID: PMC5934362 DOI: 10.1038/s41598-018-25171-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/17/2018] [Indexed: 12/25/2022] Open
Abstract
Cellulosomes are highly sophisticated molecular nanomachines that participate in the deconstruction of complex polysaccharides, notably cellulose and hemicellulose. Cellulosomal assembly is orchestrated by the interaction of enzyme-borne dockerin (Doc) modules to tandem cohesin (Coh) modules of a non-catalytic primary scaffoldin. In some cases, as exemplified by the cellulosome of the major cellulolytic ruminal bacterium Ruminococcus flavefaciens, primary scaffoldins bind to adaptor scaffoldins that further interact with the cell surface via anchoring scaffoldins, thereby increasing cellulosome complexity. Here we elucidate the structure of the unique Doc of R. flavefaciens FD-1 primary scaffoldin ScaA, bound to Coh 5 of the adaptor scaffoldin ScaB. The RfCohScaB5-DocScaA complex has an elliptical architecture similar to previously described complexes from a variety of ecological niches. ScaA Doc presents a single-binding mode, analogous to that described for the other two Coh-Doc specificities required for cellulosome assembly in R. flavefaciens. The exclusive reliance on a single-mode of Coh recognition contrasts with the majority of cellulosomes from other bacterial species described to date, where Docs contain two similar Coh-binding interfaces promoting a dual-binding mode. The discrete Coh-Doc interactions observed in ruminal cellulosomes suggest an adaptation to the exquisite properties of the rumen environment.
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Affiliation(s)
- Pedro Bule
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal.
| | - Virgínia M R Pires
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal
| | - Victor D Alves
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal
| | - Ana Luísa Carvalho
- UCIBIO-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - José A M Prates
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal
| | - Luís M A Ferreira
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal
| | - Steven P Smith
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Harry J Gilbert
- Institute for Cell and Molecular Biosciences, Newcastle University, The Medical School, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Ilit Noach
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Shabir Najmudin
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal
| | - Carlos M G A Fontes
- CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal. .,NZYTech genes & enzymes, Estrada do Paço do Lumiar, 1649-038, Lisboa, Portugal.
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Stern J, Moraïs S, Ben-David Y, Salama R, Shamshoum M, Lamed R, Shoham Y, Bayer EA, Mizrahi I. Assembly of Synthetic Functional Cellulosomal Structures onto the Cell Surface of Lactobacillus plantarum, a Potent Member of the Gut Microbiome. Appl Environ Microbiol 2018; 84:e00282-18. [PMID: 29453253 PMCID: PMC5881048 DOI: 10.1128/aem.00282-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/27/2022] Open
Abstract
Heterologous display of enzymes on microbial cell surfaces is an extremely desirable approach, since it enables the engineered microbe to interact directly with the plant wall extracellular polysaccharide matrix. In recent years, attempts have been made to endow noncellulolytic microbes with genetically engineered cellulolytic capabilities for improved hydrolysis of lignocellulosic biomass and for advanced probiotics. Thus far, however, owing to the hurdles encountered in secreting and assembling large, intricate complexes on the bacterial cell wall, only free cellulases or relatively simple cellulosome assemblies have been introduced into live bacteria. Here, we employed the "adaptor scaffoldin" strategy to compensate for the low levels of protein displayed on the bacterial cell surface. That strategy mimics natural elaborated cellulosome architectures, thus exploiting the exponential features of their Lego-like combinatorics. Using this approach, we produced several bacterial consortia of Lactobacillus plantarum, a potent gut microbe which provides a very robust genetic framework for lignocellulosic degradation. We successfully engineered surface display of large, fully active self-assembling cellulosomal complexes containing an unprecedented number of catalytic subunits all produced in vivo by the cell consortia. Our results demonstrate that the enzyme stability and performance of the cellulosomal machinery, which are superior to those seen with the equivalent secreted free enzyme system, and the high cellulase-to-xylanase ratios proved beneficial for efficient degradation of wheat straw.IMPORTANCE The multiple benefits of lactic acid bacteria are well established in health and industry. Here we present an approach designed to extensively increase the cell surface display of proteins via successive assembly of interactive components. Our findings present a stepping stone toward proficient engineering of Lactobacillus plantarum, a widespread, environmentally important bacterium and potent microbiome member, for improved degradation of lignocellulosic biomass and advanced probiotics.
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Affiliation(s)
- Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yonit Ben-David
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Rachel Salama
- Department of Biotechnology and Food Engineering, The Technion Israel Institute of Technology, Haifa, Israel
| | - Melina Shamshoum
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Israel
| | - Yuval Shoham
- Department of Biotechnology and Food Engineering, The Technion Israel Institute of Technology, Haifa, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Itzhak Mizrahi
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Colocalization and Disposition of Cellulosomes in Clostridium clariflavum as Revealed by Correlative Superresolution Imaging. mBio 2018; 9:mBio.00012-18. [PMID: 29437917 PMCID: PMC5801460 DOI: 10.1128/mbio.00012-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellulosomes are multienzyme complexes produced by anaerobic, cellulolytic bacteria for highly efficient breakdown of plant cell wall polysaccharides. Clostridium clariflavum is an anaerobic, thermophilic bacterium that produces the largest assembled cellulosome complex in nature to date, comprising three types of scaffoldins: a primary scaffoldin, ScaA; an adaptor scaffoldin, ScaB; and a cell surface anchoring scaffoldin, ScaC. This complex can contain 160 polysaccharide-degrading enzymes. In previous studies, we proposed potential types of cellulosome assemblies in C. clariflavum and demonstrated that these complexes are released into the extracellular medium. In the present study, we explored the disposition of the highly structured, four-tiered cell-anchored cellulosome complex of this bacterium. Four separate, integral cellulosome components were subjected to immunolabeling: ScaA, ScaB, ScaC, and the cellulosome’s most prominent enzyme, GH48. Imaging of the cells by correlating scanning electron microscopy and three-dimensional (3D) superresolution fluorescence microscopy revealed that some of the protuberance-like structures on the cell surface represent cellulosomes and that the components are highly colocalized and organized by a defined hierarchy on the cell surface. The display of the cellulosome on the cell surface was found to differ between cells grown on soluble or insoluble substrates. Cell growth on microcrystalline cellulose and wheat straw exhibited dramatic enhancement in the amount of cellulosomes displayed on the bacterial cell surface. Conversion of plant biomass into soluble sugars is of high interest for production of fermentable industrial materials, such as biofuels. Biofuels are a very attractive alternative to fossil fuels, both for recycling of agricultural wastes and as a source of sustainable energy. Cellulosomes are among the most efficient enzymatic degraders of biomass known to date, due to the incorporation of a multiplicity of enzymes into a potent, multifunctional nanomachine. The intimate association with the bacterial cell surface is inherent in its efficient action on lignocellulosic substrates, although this property has not been properly addressed experimentally. The dramatic increase in cellulosome performance on recalcitrant feedstocks is critical for the design of cost-effective processes for efficient biomass degradation.
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31
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Yoav S, Salame TM, Feldman D, Levinson D, Ioelovich M, Morag E, Yarden O, Bayer EA, Hadar Y. Effects of cre1 modification in the white-rot fungus Pleurotus ostreatus PC9: altering substrate preference during biological pretreatment. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:212. [PMID: 30065786 PMCID: PMC6062969 DOI: 10.1186/s13068-018-1209-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 07/18/2018] [Indexed: 05/16/2023]
Abstract
BACKGROUND During the process of bioethanol production, cellulose is hydrolyzed into its monomeric soluble units. For efficient hydrolysis, a chemical and/or mechanical pretreatment step is required. Such pretreatment is designed to increase enzymatic digestibility of the cellulose chains inter alia by de-crystallization of the cellulose chains and by removing barriers, such as lignin from the plant cell wall. Biological pretreatment, in which lignin is decomposed or modified by white-rot fungi, has also been considered. One disadvantage in biological pretreatment, however, is the consumption of the cellulose by the fungus. Thus, fungal species that attack lignin with only minimal cellulose loss are advantageous. The secretomes of white-rot fungi contain carbohydrate-active enzymes (CAZymes) including lignin-modifying enzymes. Thus, modification of secretome composition can alter the ratio of lignin/cellulose degradation. RESULTS Pleurotus ostreatus PC9 was genetically modified to either overexpress or eliminate (by gene replacement) the transcriptional regulator CRE1, known to act as a repressor in the process of carbon catabolite repression. The cre1-overexpressing transformant demonstrated lower secreted cellulolytic activity and slightly increased selectivity (based on the chemical composition of pretreated wheat straw), whereas the knockout transformant demonstrated increased cellulolytic activity and significantly reduced residual cellulose, thereby displaying lower selectivity. Pretreatment of wheat straw using the wild-type PC9 resulted in 2.8-fold higher yields of soluble sugar compared to untreated wheat straw. The overexpression transformant showed similar yields (2.6-fold), but the knockout transformant exhibited lower yields (1.2-fold) of soluble sugar. Based on proteomic secretome analysis, production of numerous CAZymes was affected by modification of the expression level of cre1. CONCLUSIONS The gene cre1 functions as a regulator for expression of fungal CAZymes active against plant cell wall lignocelluloses, hence altering the substrate preference of the fungi tested. While the cre1 knockout resulted in a less efficient biological pretreatment, i.e., less saccharification of the treated biomass, the converse manipulation of cre1 (overexpression) failed to improve efficiency. Despite the inverse nature of the two genetic alterations, the expected "mirror image" (i.e., opposite regulatory response) was not observed, indicating that the secretion level of CAZymes, was not exclusively dependent on CRE1 activity.
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Affiliation(s)
- Shahar Yoav
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100 Israel
| | - Tomer M. Salame
- Flow Cytometry Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Daria Feldman
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100 Israel
| | - Dana Levinson
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100 Israel
| | | | - Ely Morag
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100 Israel
| | - Edward A. Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Yitzhak Hadar
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100 Israel
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Ying W, Shi Z, Yang H, Xu G, Zheng Z, Yang J. Effect of alkaline lignin modification on cellulase-lignin interactions and enzymatic saccharification yield. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:214. [PMID: 30083227 PMCID: PMC6069831 DOI: 10.1186/s13068-018-1217-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/25/2018] [Indexed: 05/06/2023]
Abstract
BACKGROUND The lignin can compete for binding cellulase enzymes with cellulose fibers and decrease the accessibility of enzymes to carbohydrates. The competitive adsorption of cellulase to lignin mainly depended on the chemical structure of lignin. The post-pretreatment can decrease the lignin content and modify the lignin structure of pretreated substrates, which reduced the lignin inhibition on enzymatic saccharification. Therefore, the post-treatment by modifying the lignin structure would attract considerable attention for weakening the cellulase-lignin interactions. RESULTS Three modified lignins, including sulfonated lignin (SL), oxidized lignin (OL), and carboxylated lignin (CL), were prepared from alkali lignin (AL) and their structures and physicochemical properties were characterized using FTIR, NMR, XPS analysis, zeta potential, and contact angle, respectively. Compared to AL, three modified lignin preparations exhibited the decrease in contact angle by 61-70% and phenolic hydroxyls content by 17-80%, and an obvious increase of negative charges by about 21-45%. This was mainly due to the drop of condensation degree and the incorporation of carboxylic and sulfonic acid groups into modified lignins. Langmuir adsorption isotherms showed that the affinity strength between cellulase and modified lignins significantly reduced by 54-80%. Therefore, the 72 h hydrolysis yield of Avicel with SL, OL, and CL was 48.5, 51.3, and 49.4%, respectively, which was increased 8-15.3% than that of Avicel with AL, 44.5%. In the enzymatic hydrolysis of bamboo biomass, the glucose yield at 5 d was 38.5% for AS-P. amarus, 15.4% for AO-P. amarus and 21.4% for AC-P. amarus, respectively, which were 1.4-3.5 times of alkali pretreated P. amarus. CONCLUSIONS The post-treatment can weaken the nonproductive adsorption between lignin and cellulase proteins and improve the enzymatic saccharification efficiency. This study will provide a conceptual combination of pretreatment technologies and post-pretreatment by modifying lignin structure for reducing the cellulase-lignin interaction.
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Affiliation(s)
- Wenjun Ying
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, 650224 China
- School of Chemical Engineering, Southwest Forestry University, Kunming, 650224 China
| | - Zhengjun Shi
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, 650224 China
- School of Chemical Engineering, Southwest Forestry University, Kunming, 650224 China
| | - Haiyan Yang
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, 650224 China
- School of Chemical Engineering, Southwest Forestry University, Kunming, 650224 China
| | - Gaofeng Xu
- School of Chemical Engineering, Southwest Forestry University, Kunming, 650224 China
| | - Zhifeng Zheng
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, 650224 China
| | - Jing Yang
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, 650224 China
- School of Chemical Engineering, Southwest Forestry University, Kunming, 650224 China
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Chen Q, Yu S, Myung N, Chen W. DNA-guided assembly of a five-component enzyme cascade for enhanced conversion of cellulose to gluconic acid and H 2 O 2. J Biotechnol 2017; 263:30-35. [DOI: 10.1016/j.jbiotec.2017.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/25/2017] [Accepted: 10/09/2017] [Indexed: 01/17/2023]
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Thomas VA, Donohoe BS, Li M, Pu Y, Ragauskas AJ, Kumar R, Nguyen TY, Cai CM, Wyman CE. Adding tetrahydrofuran to dilute acid pretreatment provides new insights into substrate changes that greatly enhance biomass deconstruction by Clostridium thermocellum and fungal enzymes. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:252. [PMID: 29213312 PMCID: PMC5707920 DOI: 10.1186/s13068-017-0937-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/19/2017] [Indexed: 05/11/2023]
Abstract
BACKGROUND Consolidated bioprocessing (CBP) by anaerobes, such as Clostridium thermocellum, which combine enzyme production, hydrolysis, and fermentation are promising alternatives to historical economic challenges of using fungal enzymes for biological conversion of lignocellulosic biomass. However, limited research has integrated CBP with real pretreated biomass, and understanding how pretreatment impacts subsequent deconstruction by CBP vs. fungal enzymes can provide valuable insights into CBP and suggest other novel biomass deconstruction strategies. This study focused on determining the effect of pretreatment by dilute sulfuric acid alone (DA) and with tetrahydrofuran (THF) addition via co-solvent-enhanced lignocellulosic fractionation (CELF) on deconstruction of corn stover and Populus with much different recalcitrance by C. thermocellum vs. fungal enzymes and changes in pretreated biomass related to these differences. RESULTS Coupling CELF fractionation of corn stover and Populus with subsequent CBP by the anaerobe C. thermocellum completely solubilized polysaccharides left in the pretreated solids within only 48 h without adding enzymes. These results were better than those from the conventional DA followed by either CBP or fungal enzymes or CELF followed by fungal enzyme hydrolysis, especially at viable enzyme loadings. Enzyme adsorption on CELF-pretreated corn stover and CELF-pretreated Populus solids were virtually equal, while DA improved the enzyme accessibility for corn stover more than Populus. Confocal scanning light microscopy (CSLM), transmission electron microscopy (TEM), and NMR characterization of solids from both pretreatments revealed differences in cell wall structure and lignin composition, location, coalescence, and migration-enhanced digestibility of CELF-pretreated solids. CONCLUSIONS Adding THF to DA pretreatment (CELF) greatly enhanced deconstruction of corn stover and Populus by fungal enzymes and C. thermocellum CBP, and the CELF-CBP tandem was agnostic to feedstock recalcitrance. Composition measurements, material balances, cellulase adsorption, and CSLM and TEM imaging revealed adding THF enhanced the enzyme accessibility, cell wall fractures, and cellular dislocation and cell wall delamination. Overall, enhanced deconstruction of CELF solids by enzymes and particularly by C. thermocellum could be related to lignin removal and alteration, thereby pointing to these factors being key contributors to biomass recalcitrance as a barrier to low-cost biological conversion to sustainable fuels.
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Affiliation(s)
- Vanessa A. Thomas
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Bryon S. Donohoe
- National Renewable Energy Laboratory, Golden, CO USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Mi Li
- Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Yunqiao Pu
- Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Arthur J. Ragauskas
- Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- Department of Chemical & Bimolecular Engineering, Center for Renewable Carbon and Department of Forestry, Wildlife, and Fisheries, University of Tennessee Knoxville, Knoxville, TN USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Rajeev Kumar
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Thanh Yen Nguyen
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- Department of Bioengineering, Bourns College of Engineering, University of California Riverside, Riverside, CA USA
| | - Charles M. Cai
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Charles E. Wyman
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- Department of Bioengineering, Bourns College of Engineering, University of California Riverside, Riverside, CA USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
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Pan-Cellulosomics of Mesophilic Clostridia: Variations on a Theme. Microorganisms 2017; 5:microorganisms5040074. [PMID: 29156585 PMCID: PMC5748583 DOI: 10.3390/microorganisms5040074] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 11/17/2022] Open
Abstract
The bacterial cellulosome is an extracellular, multi-enzyme machinery, which efficiently depolymerizes plant biomass by degrading plant cell wall polysaccharides. Several cellulolytic bacteria have evolved various elaborate modular architectures of active cellulosomes. We present here a genome-wide analysis of a dozen mesophilic clostridia species, including both well-studied and yet-undescribed cellulosome-producing bacteria. We first report here, the presence of cellulosomal elements, thus expanding our knowledge regarding the prevalence of the cellulosomal paradigm in nature. We explored the genomic organization of key cellulosome components by comparing the cellulosomal gene clusters in each bacterial species, and the conserved sequence features of the specific cellulosomal modules (cohesins and dockerins), on the background of their phylogenetic relationship. Additionally, we performed comparative analyses of the species-specific repertoire of carbohydrate-degrading enzymes for each of the clostridial species, and classified each cellulosomal enzyme into a specific CAZy family, thus indicating their putative enzymatic activity (e.g., cellulases, hemicellulases, and pectinases). Our work provides, for this large group of bacteria, a broad overview of the blueprints of their multi-component cellulosomal complexes. The high similarity of their scaffoldin clusters and dockerin-based recognition residues suggests a common ancestor, and/or extensive horizontal gene transfer, and potential cross-species recognition. In addition, the sporadic spatial organization of the numerous dockerin-containing genes in several of the genomes, suggests the importance of the cellulosome paradigm in the given bacterial species. The information gained in this work may be utilized directly or developed further by genetically engineering and optimizing designer cellulosome systems for enhanced biotechnological biomass deconstruction and biofuel production.
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Setter-Lamed E, Moraïs S, Stern J, Lamed R, Bayer EA. Modular Organization of the Thermobifida fusca Exoglucanase Cel6B Impacts Cellulose Hydrolysis and Designer Cellulosome Efficiency. Biotechnol J 2017; 12. [PMID: 28901714 DOI: 10.1002/biot.201700205] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/06/2017] [Indexed: 11/09/2022]
Abstract
Cellulose deconstruction can be achieved by three distinct enzymatic paradigms: free enzymes, multifunctional enzymes, and self-assembled, multi-enzyme complexes (cellulosomes). To study their comparative efficiency, the simple and efficient cellulolytic system of the aerobic bacterium, Thermobifida fusca, is developed as an enzymatic model. In previous studies, most of its cellulases are successfully converted to the cellulosomal mode and exhibited high cellulolytic activities, except for Cel6B, a key exoglucanase of the T. fusca enzymatic system. Here, the impact of the modular organization of Cel6B on enzymatic activity is investigated. The position of the cellulose-binding module (CBM), its family and linker segment are shown to affect activity. Surprisingly, exchange of the native family-2 CBM to family-3 generates an increase in Cel6B activity on cellulosic substrates. Conversion of Cel6B to the cellulosomal mode by fusing a cohesin to the catalytic module enables formation of divalent enzyme complexes with dockerin-bearing enzymes. The resultant pseudo-cellulosomes, containing Cel6B combined with endoglucanase Cel5A, exhibits enhanced enzymatic activity, compared to mixtures of wild-type enzymes or bifunctional enzymes, unlike similar pseudo-cellulosomes containing endoglucanase Cel6A or proccessive endoglucanase Cel9A. Insight into the different enzymatic paradigms benefits ongoing development of efficient cellulolytic systems for conversion of plant-derived biomass into valuable sugars. NOVELTY STATEMENT The protein engineering of the modular arrangement of a key exoglucanase from a highly cellulolytic bacterium, Thermobifida fusca, served to explore and compare three major enzymatic paradigms for cellulose degradation. This approach revealed highly active chimaeric forms of the exoglucanase that act in synergy together with a potent endoglucanase in bifunctional enzymes or divalent pseudo-cellulosome-like complexes. Such engineered enzymes could be further integrated into larger enzymatic complexes, thereby providing a significant step forward towards conversion of the entire T. fusca free cellulolytic system into the cellulosomal modex and the enhanced conversion of cellulosic biomass into soluble sugars.
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Affiliation(s)
- Eva Setter-Lamed
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
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Szczupak A, Aizik D, Moraïs S, Vazana Y, Barak Y, Bayer EA, Alfonta L. The Electrosome: A Surface-Displayed Enzymatic Cascade in a Biofuel Cell's Anode and a High-Density Surface-Displayed Biocathodic Enzyme. NANOMATERIALS (BASEL, SWITZERLAND) 2017; 7:E153. [PMID: 28644390 PMCID: PMC5535219 DOI: 10.3390/nano7070153] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/12/2017] [Accepted: 06/20/2017] [Indexed: 11/29/2022]
Abstract
The limitation of surface-display systems in biofuel cells to a single redox enzyme is a major drawback of hybrid biofuel cells, resulting in a low copy-number of enzymes per yeast cell and a limitation in displaying enzymatic cascades. Here we present the electrosome, a novel surface-display system based on the specific interaction between the cellulosomal scaffoldin protein and a cascade of redox enzymes that allows multiple electron-release by fuel oxidation. The electrosome is composed of two compartments: (i) a hybrid anode, which consists of dockerin-containing enzymes attached specifically to cohesin sites in the scaffoldin to assemble an ethanol oxidation cascade, and (ii) a hybrid cathode, which consists of a dockerin-containing oxygen-reducing enzyme attached in multiple copies to the cohesin-bearing scaffoldin. Each of the two compartments was designed, displayed, and tested separately. The new hybrid cell compartments displayed enhanced performance over traditional biofuel cells; in the anode, the cascade of ethanol oxidation demonstrated higher performance than a cell with just a single enzyme. In the cathode, a higher copy number per yeast cell of the oxygen-reducing enzyme copper oxidase has reduced the effect of competitive inhibition resulting from yeast oxygen consumption. This work paves the way for the assembly of more complex cascades using different enzymes and larger scaffoldins to further improve the performance of hybrid cells.
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Affiliation(s)
- Alon Szczupak
- Department of Life Sciences and the Ilse Katz Institute for Nanoscale Science and Technology, P.O. Box 653, 8410501 Beer-Sheva, Israel.
| | - Dror Aizik
- Department of Life Sciences and the Ilse Katz Institute for Nanoscale Science and Technology, P.O. Box 653, 8410501 Beer-Sheva, Israel.
| | - Sarah Moraïs
- Department of Biomolecular Sciences, Weizmann Institute of Science, 234 Herzl St., P.O. Box 26, 7610001 Rehovot, Israel.
| | - Yael Vazana
- Department of Biomolecular Sciences, Weizmann Institute of Science, 234 Herzl St., P.O. Box 26, 7610001 Rehovot, Israel.
| | - Yoav Barak
- Department of Chemical Research Support, Weizmann Institute of Science, 234 Herzl St., P.O. Box 26, 7610001 Rehovot, Israel.
| | - Edward A Bayer
- Department of Biomolecular Sciences, Weizmann Institute of Science, 234 Herzl St., P.O. Box 26, 7610001 Rehovot, Israel.
| | - Lital Alfonta
- Department of Life Sciences and the Ilse Katz Institute for Nanoscale Science and Technology, P.O. Box 653, 8410501 Beer-Sheva, Israel.
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Continually emerging mechanistic complexity of the multi-enzyme cellulosome complex. Curr Opin Struct Biol 2017; 44:151-160. [DOI: 10.1016/j.sbi.2017.03.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/16/2017] [Accepted: 03/17/2017] [Indexed: 12/20/2022]
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Wang SZ, Zhang YH, Ren H, Wang YL, Jiang W, Fang BS. Strategies and perspectives of assembling multi-enzyme systems. Crit Rev Biotechnol 2017; 37:1024-1037. [PMID: 28423958 DOI: 10.1080/07388551.2017.1303803] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Multi-enzyme complexes have the potential to achieve high catalytic efficiency for sequence reactions due to their advantages in eliminating product inhibition, facilitating intermediate transfer and in situ regenerating cofactors. Constructing functional multi-enzyme systems to mimic natural multi-enzyme complexes is of great interest for multi-enzymatic biosynthesis and cell-free synthetic biotransformation, but with many challenges. Currently, various assembly strategies have been developed based on the interaction of biomacromolecules such as DNA, peptide and scaffolding protein. On the other hand, chemical-induced assembly is based on the affinity of enzymes with small molecules including inhibitors, cofactors and metal ions has the advantage of simplicity, site-to-site oriented structure control and economy. This review summarizes advances and progresses employing these strategies. Furthermore, challenges and perspectives in designing multi-enzyme systems are highlighted.
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Affiliation(s)
- Shi-Zhen Wang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China.,b The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University , Xiamen , China.,c State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University , Xiamen , China
| | - Yong-Hui Zhang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Hong Ren
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Ya-Li Wang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Wei Jiang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Bai-Shan Fang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China.,b The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University , Xiamen , China.,d The Key Laboratory for Chemical Biology of Fujian Province, Xiamen University , Xiamen , China
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Lee CC, Kibblewhite RE, Paavola CD, Orts WJ, Wagschal K. Production of Glucaric Acid from Hemicellulose Substrate by Rosettasome Enzyme Assemblies. Mol Biotechnol 2017; 58:489-96. [PMID: 27198564 DOI: 10.1007/s12033-016-9945-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hemicellulose biomass is a complex polymer with many different chemical constituents that can be utilized as industrial feedstocks. These molecules can be released from the polymer and transformed into value-added chemicals through multistep enzymatic pathways. Some bacteria produce cellulosomes which are assemblies composed of lignocellulolytic enzymes tethered to a large protein scaffold. Rosettasomes are artificial engineered ring scaffolds designed to mimic the bacterial cellulosome. Both cellulosomes and rosettasomes have been shown to facilitate much higher rates of biomass hydrolysis compared to the same enzymes free in solution. We investigated whether tethering enzymes involved in both biomass hydrolysis and oxidative transformation to glucaric acid onto a rosettasome scaffold would result in an analogous production enhancement in a combined hydrolysis and bioconversion metabolic pathway. Three different enzymes were used to hydrolyze birchwood hemicellulose and convert the substituents to glucaric acid, a top-12 DOE value added chemical feedstock derived from biomass. It was demonstrated that colocalizing the three different enzymes to the synthetic scaffold resulted in up to 40 % higher levels of product compared to uncomplexed enzymes.
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Affiliation(s)
- Charles C Lee
- Bioproducts Research Unit, USDA-ARS-WRRC, 800 Buchanan St., Albany, CA, 94710, USA.
| | - Rena E Kibblewhite
- Bioproducts Research Unit, USDA-ARS-WRRC, 800 Buchanan St., Albany, CA, 94710, USA
| | - Chad D Paavola
- NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - William J Orts
- Bioproducts Research Unit, USDA-ARS-WRRC, 800 Buchanan St., Albany, CA, 94710, USA
| | - Kurt Wagschal
- Bioproducts Research Unit, USDA-ARS-WRRC, 800 Buchanan St., Albany, CA, 94710, USA
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Artzi L, Bayer EA, Moraïs S. Cellulosomes: bacterial nanomachines for dismantling plant polysaccharides. Nat Rev Microbiol 2017; 15:83-95. [PMID: 27941816 DOI: 10.1038/nrmicro.2016.164] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cellulosomes are multienzyme complexes that are produced by anaerobic cellulolytic bacteria for the degradation of lignocellulosic biomass. They comprise a complex of scaffoldin, which is the structural subunit, and various enzymatic subunits. The intersubunit interactions in these multienzyme complexes are mediated by cohesin and dockerin modules. Cellulosome-producing bacteria have been isolated from a large variety of environments, which reflects their prevalence and the importance of this microbial enzymatic strategy. In a given species, cellulosomes exhibit intrinsic heterogeneity, and between species there is a broad diversity in the composition and configuration of cellulosomes. With the development of modern technologies, such as genomics and proteomics, the full protein content of cellulosomes and their expression levels can now be assessed and the regulatory mechanisms identified. Owing to their highly efficient organization and hydrolytic activity, cellulosomes hold immense potential for application in the degradation of biomass and are the focus of much effort to engineer an ideal microorganism for the conversion of lignocellulose to valuable products, such as biofuels.
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Affiliation(s)
- Lior Artzi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
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Bayer EA. Cellulosomes and designer cellulosomes: why toy with Nature? ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:14-15. [PMID: 27756116 DOI: 10.1111/1758-2229.12489] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100, Israel
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Stern J, Artzi L, Moraïs S, Fontes CMGA, Bayer EA. Carbohydrate Depolymerization by Intricate Cellulosomal Systems. Methods Mol Biol 2017; 1588:93-116. [PMID: 28417363 DOI: 10.1007/978-1-4939-6899-2_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Cellulosomes are multi-enzymatic nanomachines that have been fine-tuned through evolution to efficiently deconstruct plant biomass. Integration of cellulosomal components occurs via highly ordered protein-protein interactions between the various enzyme-borne dockerin modules and the multiple copies of the cohesin modules located on the scaffoldin subunit. Recently, designer cellulosome technology has been established to provide insights into the architectural role of catalytic (enzymatic) and structural (scaffoldin) cellulosomal constituents for the efficient degradation of plant cell wall polysaccharides. Owing to advances in genomics and proteomics, highly structured cellulosome complexes have recently been unraveled, and the information gained has inspired the development of designer cellulosome technology to new levels of complex organization. These higher-order designer cellulosomes have in turn fostered our capacity to enhance the catalytic potential of artificial cellulolytic complexes. In this chapter, methods to produce and employ such intricate cellulosomal complexes are reported.
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Affiliation(s)
- Johanna Stern
- Faculty of Biochemistry, Department of Biomolecular Sciences, The Weizmann Institute of Science, Ullmann Building of Life Sciences, Room 226, Rehovot, 76100, Israel
| | - Lior Artzi
- Faculty of Biochemistry, Department of Biomolecular Sciences, The Weizmann Institute of Science, Ullmann Building of Life Sciences, Room 226, Rehovot, 76100, Israel
| | - Sarah Moraïs
- Faculty of Biochemistry, Department of Biomolecular Sciences, The Weizmann Institute of Science, Ullmann Building of Life Sciences, Room 226, Rehovot, 76100, Israel
| | - Carlos M G A Fontes
- CIISA - Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal
| | - Edward A Bayer
- Faculty of Biochemistry, Department of Biomolecular Sciences, The Weizmann Institute of Science, Ullmann Building of Life Sciences, Room 226, Rehovot, 76100, Israel.
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45
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Galanopoulou AP, Moraïs S, Georgoulis A, Morag E, Bayer EA, Hatzinikolaou DG. Insights into the functionality and stability of designer cellulosomes at elevated temperatures. Appl Microbiol Biotechnol 2016; 100:8731-43. [PMID: 27207145 DOI: 10.1007/s00253-016-7594-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/23/2016] [Accepted: 04/28/2016] [Indexed: 01/21/2023]
Abstract
Enzymatic breakdown of lignocellulose is a major limiting step in second generation biorefineries. Assembly of the necessary activities into designer cellulosomes increases the productivity of this step by enhancing enzyme synergy through the proximity effect. However, most cellulosomal components are obtained from mesophilic microorganisms, limiting the applications to temperatures up to 50 °C. We hypothesized that a scaffoldin, comprising modular components of mainly mesophilic origin, can function at higher temperatures when combined with thermophilic enzymes, and the resulting designer cellulosomes could be employed in higher temperature reactions. For this purpose, we used a tetravalent scaffoldin constituted of three cohesins of mesophilic origin as well as a cohesin and cellulose-binding module derived from the thermophilic bacterium Clostridium thermocellum. The scaffoldin was combined with four thermophilic enzymes from Geobacillus and Caldicellulosiruptor species, each fused with a dockerin whose specificity matched one of the cohesins. We initially verified that the biochemical properties and thermal stability of the resulting chimeric enzymes were not affected by the presence of the mesophilic dockerins. Then we examined the stability of the individual single-enzyme-scaffoldin complexes and the full tetravalent cellulosome showing that all complexes are stable and functional for at least 6 h at 60 °C. Finally, within this time frame and conditions, the full complex appeared over 50 % more efficient in the hydrolysis of corn stover compared to the free enzymes. Overall, the results support the utilization of scaffoldin components of mesophilic origin at relatively high temperatures and provide a framework for the production of designer cellulosomes suitable for high temperature biorefinery applications.
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Affiliation(s)
- Anastasia P Galanopoulou
- Faculty of Biology, Microbiology Group, National and Kapodistrian University of Athens, Zografou Campus, 15784, Zografou, Attica, Greece
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Anastasios Georgoulis
- Faculty of Biology, Microbiology Group, National and Kapodistrian University of Athens, Zografou Campus, 15784, Zografou, Attica, Greece
| | - Ely Morag
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Dimitris G Hatzinikolaou
- Faculty of Biology, Microbiology Group, National and Kapodistrian University of Athens, Zografou Campus, 15784, Zografou, Attica, Greece.
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Davidi L, Moraïs S, Artzi L, Knop D, Hadar Y, Arfi Y, Bayer EA. Toward combined delignification and saccharification of wheat straw by a laccase-containing designer cellulosome. Proc Natl Acad Sci U S A 2016; 113:10854-9. [PMID: 27621442 PMCID: PMC5047212 DOI: 10.1073/pnas.1608012113] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Efficient breakdown of lignocellulose polymers into simple molecules is a key technological bottleneck limiting the production of plant-derived biofuels and chemicals. In nature, plant biomass degradation is achieved by the action of a wide range of microbial enzymes. In aerobic microorganisms, these enzymes are secreted as discrete elements in contrast to certain anaerobic bacteria, where they are assembled into large multienzyme complexes termed cellulosomes. These complexes allow for very efficient hydrolysis of cellulose and hemicellulose due to the spatial proximity of synergistically acting enzymes and to the limited diffusion of the enzymes and their products. Recently, designer cellulosomes have been developed to incorporate foreign enzymatic activities in cellulosomes so as to enhance lignocellulose hydrolysis further. In this study, we complemented a cellulosome active on cellulose and hemicellulose by addition of an enzyme active on lignin. To do so, we designed a dockerin-fused variant of a recently characterized laccase from the aerobic bacterium Thermobifida fusca The resultant chimera exhibited activity levels similar to the wild-type enzyme and properly integrated into the designer cellulosome. The resulting complex yielded a twofold increase in the amount of reducing sugars released from wheat straw compared with the same system lacking the laccase. The unorthodox use of aerobic enzymes in designer cellulosome machinery effects simultaneous degradation of the three major components of the plant cell wall (cellulose, hemicellulose, and lignin), paving the way for more efficient lignocellulose conversion into soluble sugars en route to alternative fuels production.
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Affiliation(s)
- Lital Davidi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lior Artzi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Doriv Knop
- Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Yitzhak Hadar
- Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Yonathan Arfi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel;
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Zhang J, Hou H, Chen G, Wang S, Zhang J. The isolation and functional identification on producing cellulase of Pseudomonas mendocina. Bioengineered 2016; 7:382-391. [PMID: 27710430 DOI: 10.1080/21655979.2016.1227143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The straw can be degraded efficiently into humus by powerful enzymes from microorganisms, resulting in the accelerated circulation of N,P,K and other effective elements in ecological system. We isolated a strain through screening the straw degradation strains from natural humic straw in the low temperature area in northeast of china, which can produce cellulase efficiently. The strain was identified as Pseudomonas mendocina by using morphological, physiological, biochemical test, and molecular biological test, with the functional clarification on producing cellulase for Pseudomonas mendocina for the first time. The enzyme force constant Km and the maximum reaction rate (Vmax) of the strain were 0.3261 g/L and 0.1525 mg/(min.L) through the enzyme activity detection, and the molecular weight of the enzyme produced by the strain were 42.4 kD and 20.4 kD based on SDS-PAGE. The effects of various ecological factors such as temperature, pH and nematodes on the enzyme produced by the strain in the micro ecosystem in plant roots were evaluated. The result showed that the optimum temperature was 28°C, and the best pH was 7.4∼7.8, the impact heavy metal was Pb2+ and the enzyme activity and biomass of Pseudomonas mendocina increased the movement and predation of nematodes.
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Affiliation(s)
- Jianfeng Zhang
- a Bioengineering Department, School of Life Sciences , Jilin Agricultural University, Jilin Province Innovation Platform of Straw Comprehensive Utilization Technology , Changchun , P. R. China
| | - Hongyan Hou
- a Bioengineering Department, School of Life Sciences , Jilin Agricultural University, Jilin Province Innovation Platform of Straw Comprehensive Utilization Technology , Changchun , P. R. China
| | - Guang Chen
- a Bioengineering Department, School of Life Sciences , Jilin Agricultural University, Jilin Province Innovation Platform of Straw Comprehensive Utilization Technology , Changchun , P. R. China
| | - Shusheng Wang
- a Bioengineering Department, School of Life Sciences , Jilin Agricultural University, Jilin Province Innovation Platform of Straw Comprehensive Utilization Technology , Changchun , P. R. China
| | - Jiejing Zhang
- a Bioengineering Department, School of Life Sciences , Jilin Agricultural University, Jilin Province Innovation Platform of Straw Comprehensive Utilization Technology , Changchun , P. R. China
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Moraïs S, Stern J, Kahn A, Galanopoulou AP, Yoav S, Shamshoum M, Smith MA, Hatzinikolaou DG, Arnold FH, Bayer EA. Enhancement of cellulosome-mediated deconstruction of cellulose by improving enzyme thermostability. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:164. [PMID: 27493686 PMCID: PMC4973527 DOI: 10.1186/s13068-016-0577-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 07/27/2016] [Indexed: 05/25/2023]
Abstract
BACKGROUND The concerted action of three complementary cellulases from Clostridium thermocellum, engineered to be stable at elevated temperatures, was examined on a cellulosic substrate and compared to that of the wild-type enzymes. Exoglucanase Cel48S and endoglucanase Cel8A, both key elements of the natural cellulosome from this bacterium, were engineered previously for increased thermostability, either by SCHEMA, a structure-guided, site-directed protein recombination method, or by consensus-guided mutagenesis combined with random mutagenesis using error-prone PCR, respectively. A thermostable β-glucosidase BglA mutant was also selected from a library generated by error-prone PCR that will assist the two cellulases in their methodic deconstruction of crystalline cellulose. The effects of a thermostable scaffoldin versus those of a largely mesophilic scaffoldin were also examined. By improving the stability of the enzyme subunits and the structural component, we aimed to improve cellulosome-mediated deconstruction of cellulosic substrates. RESULTS The results demonstrate that the combination of thermostable enzymes as free enzymes and a thermostable scaffoldin was more active on the cellulosic substrate than the wild-type enzymes. Significantly, "thermostable" designer cellulosomes exhibited a 1.7-fold enhancement in cellulose degradation compared to the action of conventional designer cellulosomes that contain the respective wild-type enzymes. For designer cellulosome formats, the use of the thermostabilized scaffoldin proved critical for enhanced enzymatic performance under conditions of high temperatures. CONCLUSIONS Simple improvement in the activity of a given enzyme does not guarantee its suitability for use in an enzyme cocktail or as a designer cellulosome component. The true merit of improvement resides in its ultimate contribution to synergistic action, which can only be determined experimentally. The relevance of the mutated thermostable enzymes employed in this study as components in multienzyme systems has thus been confirmed using designer cellulosome technology. Enzyme integration via a thermostable scaffoldin is critical to the ultimate stability of the complex at higher temperatures. Engineering of thermostable cellulases and additional lignocellulosic enzymes may prove a determinant parameter for development of state-of-the-art designer cellulosomes for their employment in the conversion of cellulosic biomass to soluble sugars.Graphical abstractConversion of conventional designer cellulosomes into thermophilic designer cellulosomes.
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Affiliation(s)
- Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Amaranta Kahn
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Anastasia P. Galanopoulou
- Microbiology Group, Faculty of Biology, National and Kapodistrian University of Athens, Zografou Campus, 15784 Athens, Greece
| | - Shahar Yoav
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
- Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, P.O. Box 12, 76100 Rehovot, Israel
| | - Melina Shamshoum
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Matthew A. Smith
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 USA
| | - Dimitris G. Hatzinikolaou
- Microbiology Group, Faculty of Biology, National and Kapodistrian University of Athens, Zografou Campus, 15784 Athens, Greece
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 USA
| | - Edward A. Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
- Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
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Gunnoo M, Cazade PA, Galera-Prat A, Nash MA, Czjzek M, Cieplak M, Alvarez B, Aguilar M, Karpol A, Gaub H, Carrión-Vázquez M, Bayer EA, Thompson D. Nanoscale Engineering of Designer Cellulosomes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:5619-47. [PMID: 26748482 DOI: 10.1002/adma.201503948] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/01/2015] [Indexed: 05/27/2023]
Abstract
Biocatalysts showcase the upper limit obtainable for high-speed molecular processing and transformation. Efforts to engineer functionality in synthetic nanostructured materials are guided by the increasing knowledge of evolving architectures, which enable controlled molecular motion and precise molecular recognition. The cellulosome is a biological nanomachine, which, as a fundamental component of the plant-digestion machinery from bacterial cells, has a key potential role in the successful development of environmentally-friendly processes to produce biofuels and fine chemicals from the breakdown of biomass waste. Here, the progress toward so-called "designer cellulosomes", which provide an elegant alternative to enzyme cocktails for lignocellulose breakdown, is reviewed. Particular attention is paid to rational design via computational modeling coupled with nanoscale characterization and engineering tools. Remaining challenges and potential routes to industrial application are put forward.
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Affiliation(s)
- Melissabye Gunnoo
- Materials and Surface Science Institute and Department of Physics and Energy, University of Limerick, Limerick, Ireland
| | - Pierre-André Cazade
- Materials and Surface Science Institute and Department of Physics and Energy, University of Limerick, Limerick, Ireland
| | - Albert Galera-Prat
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas (CSIC), IMDEA Nanociencias and CIBERNED, Madrid, Spain
| | - Michael A Nash
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University, 80799, Munich, Germany
| | - Mirjam Czjzek
- Sorbonne Universités, UPMC, Université Paris 06, and Centre National de la Recherche Scientifique, UMR 8227, Integrative Biology of Marine Models, Station Biologique, de Roscoff, CS 90074, F-29688, Roscoff cedex, Bretagne, France
| | - Marek Cieplak
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Beatriz Alvarez
- Biopolis S.L., Parc Científic de la Universitat de Valencia, Edificio 2, C/Catedrático Agustín Escardino 9, 46980, Paterna (Valencia), Spain
| | - Marina Aguilar
- Abengoa, S.A., Palmas Altas, Calle Energía Solar nº 1, 41014, Seville, Spain
| | - Alon Karpol
- Designer Energy Ltd., 2 Bergman St., Tamar Science Park, Rehovot, 7670504, Israel
| | - Hermann Gaub
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University, 80799, Munich, Germany
| | - Mariano Carrión-Vázquez
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas (CSIC), IMDEA Nanociencias and CIBERNED, Madrid, Spain
| | - Edward A Bayer
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Damien Thompson
- Materials and Surface Science Institute and Department of Physics and Energy, University of Limerick, Limerick, Ireland
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Abstract
Designer cellulosomes consist of chimeric cohesin-bearing scaffoldins for the controlled incorporation of recombinant dockerin-containing enzymes. The largest designer cellulosome reported to date is a chimeric scaffoldin that contains 6 cohesins. This scaffoldin represented a technical limit of sorts, since adding another cohesin proved problematic, owing to resultant low expression levels, instability (cleavage) of the scaffoldin polypeptide, and limited numbers of available cohesin-dockerin specificities—the hallmark of designer cellulosomes. Nevertheless, increasing the number of enzymes integrated into designer cellulosomes is critical, in order to further enhance degradation of plant cell wall material. Adaptor scaffoldins comprise an intermediate type of scaffoldin that can both incorporate various enzymes and attach to an additional scaffoldin. Using this strategy, we constructed an efficient form of adaptor scaffoldin that possesses three type I cohesins for enzyme integration, a single type II dockerin for interaction with an additional scaffoldin, and a carbohydrate-binding module for targeting to the cellulosic substrate. In parallel, we designed a hexavalent scaffoldin capable of connecting to the adaptor scaffoldin by the incorporation of an appropriate type II cohesin. The resultant extended designer cellulosome comprised 8 recombinant enzymes—4 xylanases and 4 cellulases—thereby representing a potent enzymatic cocktail for solubilization of natural lignocellulosic substrates. The contribution of the adaptor scaffoldin clearly demonstrated that proximity between the two scaffoldins and their composite set of enzymes is crucial for optimized degradation. After 72 h of incubation, the performance of the extended designer cellulosome was determined to be approximately 70% compared to that of native cellulosomes. Plant cell wall residues represent a major source of renewable biomass for the production of biofuels such as ethanol via breakdown to soluble sugars. The natural microbial degradation process, however, is inefficient for achieving cost-effective processes in the conversion of plant-derived biomass to biofuels, either from dedicated crops or human-generated cellulosic wastes. The accumulation of the latter is considered a major environmental pollutant. The development of designer cellulosome nanodevices for enhanced plant cell wall degradation thus has major impacts in the fields of environmental pollution, bioenergy production, and biotechnology in general. The findings reported in this article comprise a true breakthrough in our capacity to produce extended designer cellulosomes via synthetic biology means, thus enabling the assembly of higher-order complexes that can supersede the number of enzymes included in a single multienzyme complex.
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