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Cao L, Li S, Huang X, Qin Z, Kong W, Xie W, Liu Y. Enhancing the Thermostability of Highly Active and Glucose-Tolerant β-Glucosidase Ks5A7 by Directed Evolution for Good Performance of Three Properties. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13228-13235. [PMID: 30488698 DOI: 10.1021/acs.jafc.8b05662] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A high-performance β-glucosidase for efficient cellulose hydrolysis needs to excel in thermostability, catalytic efficiency, and resistance to glucose inhibition. However, it is challenging to achieve superb properties in all three aspects in a single enzyme. In this study, a hyperactive and glucose-tolerant β-glucosidase Ks5A7 was employed as the starting point. Four rounds of random mutagenesis were then performed, giving rise to a thermostable mutant 4R1 with five amino acid substitutions. The half-life of 4R1 at 50 °C is 8640-fold that of Ks5A7 (144 h vs 1 min). Meanwhile, 4R1 had a higher specific activity (374.26 vs 243.18 units·mg-1) than the wild type with a similar glucose tolerance. When supplemented to Celluclast 1.5L, the mutant significantly enhanced the hydrolysis of pretreated sugar cane bagasse, improving the released glucose concentration by 44%. With excellent performance in thermostability, activity, and glucose tolerance, 4R1 will serve as an exceptional catalyst for industrial applications.
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Affiliation(s)
- Lichuang Cao
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , People's Republic of China
| | - Shuifeng Li
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , People's Republic of China
| | - Xin Huang
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , People's Republic of China
| | - Zongmin Qin
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , People's Republic of China
| | - Wei Kong
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , People's Republic of China
| | - Wei Xie
- Ministry of Education Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences , Sun Yat-Sen University , Guangzhou , Guangdong 510006 , People's Republic of China
| | - Yuhuan Liu
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , People's Republic of China
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Salgado JCS, Meleiro LP, Carli S, Ward RJ. Glucose tolerant and glucose stimulated β-glucosidases - A review. BIORESOURCE TECHNOLOGY 2018; 267:704-713. [PMID: 30093225 DOI: 10.1016/j.biortech.2018.07.137] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 05/22/2023]
Abstract
The β-glucosidases (β-D-glucoside glucohydrolase, EC 3.2.1.21) hydrolyze glycosidic bonds of alkyl-, amino-, or aryl-β-D-glucosides, cyanogenic glucosides, disaccharides and short oligosaccharides and can also catalyze the synthesis of glycosyl-bonds between different molecules via transglycosylation. Due to their ubiquitous phylogenetic distribution, substrate diversity and ability to both hydrolyze and synthesize glycosidic bonds, the catalysis and regulation of β-glucosidases have been extensively studied. Many β-glucosidases are inhibited by the reaction product glucose, and reduced catalytic activity may limit the biotechnological and industrial applications of these enzymes and this has stimulated the search for β-glucosidases that maintain their activity at high glucose concentrations. Studies of many glucose tolerant enzymes have been reported and due to the ongoing interest in these enzymes, here it has been reviewed this accumulated body of knowledge which provides valuable insights as to the kinetics, structure, regulation and evolution of glucose tolerant and glucose stimulated β-glucosidases.
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Affiliation(s)
- José Carlos Santos Salgado
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luana Parras Meleiro
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Sibeli Carli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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da Costa SG, Pereira OL, Teixeira-Ferreira A, Valente RH, de Rezende ST, Guimarães VM, Genta FA. Penicillium citrinum UFV1 β-glucosidases: purification, characterization, and application for biomass saccharification. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:226. [PMID: 30151054 PMCID: PMC6100729 DOI: 10.1186/s13068-018-1226-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/11/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND β-Glucosidases are components of the cellulase system, a family of enzymes that hydrolyze the β-1,4 linkages of cellulose. These proteins have been extensively studied due to the possibility of their use in various biotechnological processes. They have different affinities for substrates (depending on their source) and their activities can be used for saccharification of different types of biomass. In this context, the properties and the synergistic capacity of β-glucosidases from different organisms, to supplement the available commercial cellulase cocktails, need a comprehensive evaluation. RESULTS Two β-glucosidases belonging to GH3 family were secreted by Penicillium citrinum UFV. PcβGlu1 (241 kDa) and PcβGlu2 (95 kDa) presented acidic and thermo-tolerant characteristics. PcβGlu1 showed Michaelis-Menten kinetics for all substrates tested with Km values ranging from 0.09 ± 0.01 (laminarin) to 1.7 ± 0.1 mM (cellobiose, C2) and kcat values ranging from 0.143 ± 0.005 (laminarin) to 8.0 ± 0.2 s-1 (laminaribiose, Lb). PcβGlu2 showed substrate inhibition for 4-methylumbelliferyl-β-d-glucopyranoside (MUβGlu), p-nitrophenyl-β-d-glucopyranoside (pNPβGlu), cellodextrins (C3, C4, and C5), N-octil-β-d-glucopyranoside, and laminaribiose, with Km values ranging from 0.014 ± 0.001 (MUβGlu) to 0.64 ± 0.06 mM (C2) and kcat values ranging from 0.49 ± 0.01 (gentiobiose) to 1.5 ± 0.2 s-1 (C4). Inhibition constants (Ki) for PcβGlu2 substrate inhibition ranged from 0.69 ± 0.07 (MUβGlu) to 10 ± 1 mM (Lb). Glucose and cellobiose are competitive inhibitors of PcβGlu1 and PcβGlu2 when pNPβGlu is used as a substrate. For PcβGlu1 inhibition, Ki = 1.89 ± 0.08 mM (glucose) and Ki = 3.8 ± 0.1 mM (cellobiose); for PcβGlu2, Ki = 0.83 ± 0.05 mM (glucose) and Ki = 0.95 ± 0.07 mM (cellobiose). The enzymes were tested for saccharification of different biomasses, individually or supplementing a Trichoderma reesei commercial cellulose preparation. PcβGlu2 was able to hydrolyze banana pseudostem and coconut fiber with the same efficiency as the T. reesei cocktail, showing significant synergistic properties with T. reesei enzymes in the hydrolysis of these alternative biomasses. CONCLUSIONS The β-glucosidases from P. citrinum UFV1 present different enzymatic properties from each other and might have potential application in several biotechnological processes, such as hydrolysis of different types of biomass.
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Affiliation(s)
- Samara G. da Costa
- Laboratory of Enzymatic Technology, Department of Biochemistry and Molecular Biology, Federal University of Viçosa, Viçosa, MG CEP3657000 Brazil
- Laboratory of Insect Biochemistry and Physiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Av Brasil 4365, Pav. Leônidas Deane, Room 207, Manguinhos, RJ CEP21040360 Brazil
| | - Olinto Liparini Pereira
- Laboratory of Seed Pathology and Post-Harvest, Department of Phytopathology, Federal University of Viçosa, Viçosa, MG CEP36570-000 Brazil
| | - André Teixeira-Ferreira
- Laboratory of Toxinology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ CEP21040360 Brazil
| | - Richard Hemmi Valente
- Laboratory of Toxinology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ CEP21040360 Brazil
| | - Sebastião T. de Rezende
- Laboratory of Enzymatic Technology, Department of Biochemistry and Molecular Biology, Federal University of Viçosa, Viçosa, MG CEP3657000 Brazil
| | - Valéria M. Guimarães
- Laboratory of Enzymatic Technology, Department of Biochemistry and Molecular Biology, Federal University of Viçosa, Viçosa, MG CEP3657000 Brazil
| | - Fernando Ariel Genta
- Laboratory of Insect Biochemistry and Physiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Av Brasil 4365, Pav. Leônidas Deane, Room 207, Manguinhos, RJ CEP21040360 Brazil
- National Institute of Science and Technology for Molecular Entomology, Rio de Janeiro, RJ Brazil
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Watanabe M, Matsuzawa T, Yaoi K. Rational protein design for thermostabilization of glycoside hydrolases based on structural analysis. Appl Microbiol Biotechnol 2018; 102:8677-8684. [PMID: 30109396 DOI: 10.1007/s00253-018-9288-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 11/27/2022]
Abstract
Glycosidases are used in the food, chemical, and energy industries. These proteins are some of the most frequently used such enzymes, and their thermostability is essential for long-term and/or repeated use. In addition to thermostability, modification of the substrate selectivity and improvement of the glycosidase activities are also important. Thermostabilization of enzymes can be performed by directed evolution via random mutagenesis or by rational design via site-directed mutagenesis; each approach has advantages and disadvantages. In this paper, we introduce thermostabilization of glycoside hydrolases by rational protein design using site-directed mutagenesis along with X-ray crystallography and simulation modeling. We focus on the methods of thermostabilization of glycoside hydrolases by linking the N- and C-terminal ends, introducing disulfide bridges, and optimizing β-turn structures to promote hydrophobic interactions.
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Affiliation(s)
- Masahiro Watanabe
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32, Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Tomohiko Matsuzawa
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Katsuro Yaoi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan.
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Characterization of cold adapted and ethanol tolerant β-glucosidase from Bacillus cellulosilyticus and its application for directed hydrolysis of cellobiose to ethanol. Int J Biol Macromol 2018; 109:872-879. [DOI: 10.1016/j.ijbiomac.2017.11.072] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/08/2017] [Accepted: 11/10/2017] [Indexed: 01/05/2023]
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Akram F, Haq IU, Mukhtar H. Gene cloning, characterization and thermodynamic analysis of a novel multidomain hyperthermophilic GH family 3 β-glucosidase (TnBglB) from Thermotoga naphthophila RKU-10T. Process Biochem 2018. [DOI: 10.1016/j.procbio.2017.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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57
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Meleiro LP, Carli S, Fonseca-Maldonado R, da Silva Torricillas M, Zimbardi ALRL, Ward RJ, Jorge JA, Furriel RPM. Overexpression of a Cellobiose-Glucose-Halotolerant Endoglucanase from Scytalidium thermophilum. Appl Biochem Biotechnol 2017; 185:316-333. [PMID: 29150773 DOI: 10.1007/s12010-017-2660-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/13/2017] [Indexed: 11/28/2022]
Abstract
Enzyme reaction products and by-products from pretreatment steps can inhibit endoglucanases and are major factors limiting the efficiency of enzymatic lignocellulosic biomass hydrolysis. The gene encoding the endoglucanase from Scytalidium thermophilum (egst) was cloned and expressed as a soluble protein in Pichia pastoris GS115. The recombinant enzyme (Egst) was monomeric (66 kDa) and showed an estimated carbohydrate content of 53.3% (w/w). The optimum temperature and pH of catalysis were 60-70 °C and pH of 5.5, respectively. The enzyme was highly stable at pH 3.0-8.0 with a half-life in water of 100 min at 65 °C. The Egst presented good halotolerance, retaining 84.1 and 71.4% of the control activity in the presence of 0.5 and 2.0 mol L-1 NaCl, respectively. Hydrolysis of medium viscosity carboxymethylcellulose (CMC) by Egst was stimulated 1.77-, 1.84-, 1.64-, and 1.8-fold by dithiothreitol, β-mercaptoethanol, cysteine, and manganese at 10, 10, 10, and 5 mmol L-1 concentration, respectively. The enzyme hydrolyzed CMC with maximal velocity and an apparent affinity constant of 432.10 ± 16.76 and 10.5 ± 2.53 mg mL-1, respectively. Furthermore, the Egst was tolerant to reaction products and able to act on pretreated fractions sugarcane bagasse demonstrating excellent properties for application in the hydrolysis of lignocellulosic biomass.
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Affiliation(s)
- Luana Parras Meleiro
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Sibeli Carli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Marcela da Silva Torricillas
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ana Lucia Ribeiro Latorre Zimbardi
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - João Atílio Jorge
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rosa Prazeres Melo Furriel
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Improved thermostability of a metagenomic glucose-tolerant β-glycosidase based on its X-ray crystal structure. Appl Microbiol Biotechnol 2017; 101:8353-8363. [DOI: 10.1007/s00253-017-8525-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/08/2017] [Accepted: 09/07/2017] [Indexed: 12/29/2022]
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Vo PQN, Husser MC, Ahmadi F, Sinha H, Shih SCC. Image-based feedback and analysis system for digital microfluidics. LAB ON A CHIP 2017; 17:3437-3446. [PMID: 28871290 DOI: 10.1039/c7lc00826k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Digital microfluidics (DMF) is a technology that provides a means of manipulating nL-μL volumes of liquids on an array of electrodes. By applying an electric potential to an electrode, these discrete droplets can be controlled in parallel which can be transported, mixed, reacted, and analyzed. Typically, an automation system is interfaced with a DMF device that uses a standard set of basic instructions written by the user to execute droplet operations. Here, we present the first feedback method for DMF that relies on imaging techniques that will allow online detection of droplets without the need to reactivate all destination electrodes. Our system consists of integrating open-source electronics with a CMOS camera and a zoom lens for acquisition of the images that will be used to detect droplets on the device. We also created an algorithm that uses a Hough transform to detect a variety of droplet sizes and to detect singular droplet dispensing and movement failures on the device. As a first test, we applied this feedback system to test droplet movement for a variety of liquids used in cell-based assays and to optimize different feedback actuation schemes to improve droplet movement fidelity. We also applied our system to a colorimetric enzymatic assay to show that our system is capable of biological analysis. Overall, we believe that using our approach of integrating imaging and feedback for DMF can provide a platform for automating biological assays with analysis.
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Affiliation(s)
- Philippe Q N Vo
- Department of Electrical and Computer Engineering, Concordia University, Montréal, Québec, Canada.
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Goswami S, Das S, Datta S. Understanding the role of residues around the active site tunnel towards generating a glucose-tolerant β-glucosidase from Agrobacterium tumefaciens 5A. Protein Eng Des Sel 2017; 30:523-530. [DOI: 10.1093/protein/gzx039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 07/10/2017] [Indexed: 12/18/2022] Open
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Synergies in coupled hydrolysis and fermentation of cellulose using a Trichoderma reesei enzyme preparation and a recombinant Saccharomyces cerevisiae strain. World J Microbiol Biotechnol 2017; 33:140. [DOI: 10.1007/s11274-017-2308-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/01/2017] [Indexed: 11/27/2022]
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Zhang J, Liu S, Li R, Hong W, Xiao Y, Feng Y, Cui Q, Liu YJ. Efficient whole-cell-catalyzing cellulose saccharification using engineered Clostridium thermocellum. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:124. [PMID: 28507596 PMCID: PMC5429504 DOI: 10.1186/s13068-017-0796-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/19/2017] [Indexed: 05/26/2023]
Abstract
BACKGROUND Cost-efficient saccharification is one of the main bottlenecks for industrial lignocellulose conversion. Clostridium thermocellum naturally degrades lignocellulose efficiently using the cellulosome, a multiprotein supermolecular complex, and thus can be potentially used as a low-cost catalyst for lignocellulose saccharification. The industrial use of C. thermocellum is restrained due largely to the inhibition of the hydrolysate cellobiose to its cellulosome. Although the supplementation of beta-glucosidase may solve the problem, the production of the enzymes greatly complicates the process and may also increase the cost of saccharification. RESULTS To conquer the feedback inhibition and establish an efficient whole-cell catalyst for highly efficient cellulose saccharification, we constructed a recombinant strain of C. thermocellum ∆pyrF::CaBglA which produced a secretory exoglucanase CelS-bearing heterologous BGL using a newly developed seamless genome editing system. Without the extra addition of enzymes, the relative saccharification level of ∆pyrF::CaBglA was stimulated by over twofolds compared to its parent strain ∆pyrF through a two-stage saccharification process with 100 g/L Avicel as the carbon source. The production of reducing sugars and the relative saccharification level were further enhanced to 490 mM and 79.4%, respectively, with increased cell density. CONCLUSIONS The high cellulose-degrading ability and sugar productivity suggested that the whole-cell-catalysis strategy for cellulose saccharification is promising, and the C. thermocellum strain ∆pyrF::CaBglA could be potentially used as an efficient whole-cell catalyst for industrial cellulose saccharification.
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Affiliation(s)
- Jie Zhang
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Shiyue Liu
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Renmin Li
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Wei Hong
- Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University), Ministry of Education, Guiyang, 550000 People’s Republic of China
| | - Yan Xiao
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
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Lee WH, Jin YS. Improved ethanol production by engineered Saccharomyces cerevisiae expressing a mutated cellobiose transporter during simultaneous saccharification and fermentation. J Biotechnol 2017; 245:1-8. [DOI: 10.1016/j.jbiotec.2017.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/30/2016] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
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Structures of a glucose-tolerant β-glucosidase provide insights into its mechanism. J Struct Biol 2017; 198:154-162. [PMID: 28189793 DOI: 10.1016/j.jsb.2017.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 01/02/2017] [Accepted: 02/07/2017] [Indexed: 11/21/2022]
Abstract
Cellulose can be converted to ethanol via the fermentation of glucose, which is considered as a promising green alternative for transportation fuels. The conversion of cellulose to glucose needs three enzymes, in which β-glucosidase (BGL) plays an essential role. However, BGL is inhibited by its own product glucose, greatly limiting its applications in industry. We previously obtained a novel BGL named Bgl6 with a high glucose tolerance. Further engineering through random mutagenesis produced a triple mutant M3 with improved thermostability. This enzyme shows promising properties for wide applications but the structural basis of the unusual properties of Bgl6 is not clear. In this study, we determined the crystal structures of Bgl6 and variants at high resolution, which provide insights into its glucose-tolerant mechanism and thermostability. Particularly, Bgl6 forms an extra channel that could be used as a secondary binding site for glucose, which may contribute to glucose tolerance. Additionally, the triple mutations could strengthen the hydrophobic interactions within the enzyme and may be responsible for the enhanced thermostability exhibited by M3, which was further confirmed by dynamic light scattering data. Lastly, structural comparison to other orthologs allows us to formulate new strategies on how to improve the catalytic efficiency of Bgl6.
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65
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Kuusk S, Väljamäe P. When substrate inhibits and inhibitor activates: implications of β-glucosidases. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:7. [PMID: 28053666 PMCID: PMC5209912 DOI: 10.1186/s13068-016-0690-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/16/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND β-glucosidases (BGs) catalyze the hydrolysis of β-glycosidic bonds in glucose derivatives. They constitute an important group of enzymes with biotechnological interest like supporting cellulases in degradation of lignocellulose to fermentable sugars. In the latter context, the glucose tolerant BGs are of particular interest. These BGs often show peculiar kinetics, including inhibitory effects of substrates and activating effects of inhibitors, such as glucose or xylose. The mechanisms behind the activating/inhibiting effects are poorly understood. The nonproductive binding of substrate is expected in cases where enzymes with multiple consecutive binding subsites are studied on substrates with a low degree of polymerization. The effects of inhibitors to BGs exerting nonproductive binding of substrate have not been discussed in the literature before. RESULTS Here, we performed analyses of different reaction schemes using the catalysis by retaining BGs as a model. We found that simple competition of inhibitor with nonproductive binding of substrate can account for the activation of enzyme by inhibitor without involving any allosteric effects. The transglycosylation to inhibitor was also able to explain the activating effect of inhibitor. For both mechanisms, the activation was caused by the increase of kcat with increasing inhibitor concentration, while kcat/Km always decreased. Therefore, the activation by inhibitor was more pronounced at high substrate concentrations. The possible contribution of the two mechanisms in the activation by inhibitor was dependent on the rate-limiting step of glycosidic bond hydrolysis as well as on whether and which glucose-unit-binding subsites are interacting. CONCLUSION Knowledge on the mechanisms of the activating/inhibiting effects of inhibitors helps the rational engineering and selection of BGs for biotechnological applications. Provided that the catalysis is consistent with the reaction schemes addressed here and underlying assumptions, the mechanism of activation by inhibitor reported here is applicable for all enzymes exerting nonproductive binding of substrate.
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Affiliation(s)
- Silja Kuusk
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, 51010 Tartu, Estonia
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, 51010 Tartu, Estonia
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Exploiting non-conserved residues to improve activity and stability of Halothermothrix orenii β-glucosidase. Appl Microbiol Biotechnol 2016; 101:1455-1463. [DOI: 10.1007/s00253-016-7904-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/17/2016] [Accepted: 09/27/2016] [Indexed: 11/26/2022]
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68
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Colabardini AC, Valkonen M, Huuskonen A, Siika-aho M, Koivula A, Goldman GH, Saloheimo M. Expression of Two Novel β-Glucosidases from Chaetomium atrobrunneum in Trichoderma reesei and Characterization of the Heterologous Protein Products. Mol Biotechnol 2016; 58:821-831. [DOI: 10.1007/s12033-016-9981-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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69
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Production of β-glucosidase from wheat bran and glycerol by Aspergillus niger in stirred tank and rotating fibrous bed bioreactors. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.07.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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70
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Increased yield of β-glucosidase-catalyzed hydrolysis reactions in the presence of betaine-type metabolite analog. Bioprocess Biosyst Eng 2016; 40:153-159. [PMID: 27655352 DOI: 10.1007/s00449-016-1684-8] [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: 05/22/2016] [Accepted: 09/14/2016] [Indexed: 10/21/2022]
Abstract
β-Glucosidases (EC 3.2.1.21), abundant enzymes distributed in animals, plants and microorganism, has been generating lots of attentions for bioethanol production from cellulosic biomass. In this study, using three different origins of β-glucosidases, glucose productivity of β-glucosidase-catalyzed hydrolysis reactions in the presence of synthetic betaine-type metabolite analog (2-N,N,N-tri-n-butylammonium) acetate, was investigated. By the addition of the analog, the hydrolysis yields for all β-glucosidases was highly improved from 4-13 to 64-100 %. To understand the factors affecting on the yield enhancements, the kinetic parameters, inhibition constants of end-product and temporal stability of β-glucosidases were compared. As a result, enhancement of the yields is mainly related to the increase in the temporal stability of β-glucosidases in the presence of the analog. The present findings lead to not only improve the glucose productivity of β-glucosidase-catalyzed hydrolysis reaction toward bioethanol production but also apply to a new stabilization method for various unstable enzymes.
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71
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Qian Y, Zhong L, Hou Y, Qu Y, Zhong Y. Characterization and Strain Improvement of a Hypercellulytic Variant, Trichoderma reesei SN1, by Genetic Engineering for Optimized Cellulase Production in Biomass Conversion Improvement. Front Microbiol 2016; 7:1349. [PMID: 27621727 PMCID: PMC5002442 DOI: 10.3389/fmicb.2016.01349] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/16/2016] [Indexed: 01/20/2023] Open
Abstract
The filamentous fungus Trichoderma reesei is a widely used strain for cellulolytic enzyme production. A hypercellulolytic T. reesei variant SN1 was identified in this study and found to be different from the well-known cellulase producers QM9414 and RUT-C30. The cellulose-degrading enzymes of T. reesei SN1 show higher endoglucanase (EG) activity but lower β-glucosidase (BGL) activity than those of the others. A uracil auxotroph strain, SP4, was constructed by pyr4 deletion in SN1 to improve transformation efficiency. The BGL1-encoding gene bgl1 under the control of a modified cbh1 promoter was overexpressed in SP4. A transformant, SPB2, with four additional copies of bgl1 exhibited a 17.1-fold increase in BGL activity and a 30.0% increase in filter paper activity. Saccharification of corncob residues with crude enzyme showed that the glucose yield of SPB2 is 65.0% higher than that of SP4. These results reveal the feasibility of strain improvement through the development of an efficient genetic transformation platform to construct a balanced cellulase system for biomass conversion.
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Affiliation(s)
- Yuanchao Qian
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University Jinan, China
| | - Lixia Zhong
- Shandong Institute for Food and Drug Control Jinan, China
| | - Yunhua Hou
- Bioengineering Institute, Qilu University of Technology Jinan, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University Jinan, China
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University Jinan, China
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72
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Arakawa G, Kamino K, Tokuda G, Watanabe H. Purification, Characterization, and cDNA Cloning of a Prominent β-Glucosidase from the Gut of the Xylophagous Cockroach Panesthia angustipennis spadica. J Appl Glycosci (1999) 2016; 63:51-59. [PMID: 34354483 PMCID: PMC8056914 DOI: 10.5458/jag.jag.jag-2016_006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 05/12/2016] [Indexed: 10/31/2022] Open
Abstract
In this study, a β-glucosidase (PaBG1b) with high specific activity was purified from gut extracts of the wood-feeding cockroach Panesthia angustipennis spadica using Superdex 75 gel filtration chromatography and High-Trap phenyl hydrophobic chromatography. The protein was purified 14-fold to a single band identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis, with an apparent molecular mass of 56.7 kDa. The specific activity of the purified enzyme was 708 μmol/min/mg protein using cellobiose as substrate. To the best of our knowledge, this is the highest specific activity reported among β-glucosidases to date. The purified PaBG1b showed optimal activity at pH 5.0 and retained more than 65 % of the activity between pH 4.0 and 6.5. The activity was stable up to 50 °C for 30 min. Kinetic studies on cellobiose revealed that the K m was 5.3 mM, and the V max was 1,020 μmol/min/mg. The internal amino acid sequence of PaBG1b was analyzed, and two continuous sequences (a total of 39 amino acids) of the C-terminal region were elucidated. Based on these amino acid sequences, a full-length cDNA (1,552 bp) encoding 502 amino acids was isolated. The encoded protein showed high similarity to β-glucosidases from glycoside hydrolase family 1. Thus, the current study demonstrated the potential of PaBG1b for application in enzymatic biomass-conversion as a donor gene for heterologous recombination of cellulase-producing agents (fungi or bacteria) or an additive enzyme for cellulase products based on the high-performance of PaBG1b as a digestive enzyme in cockroaches.
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Affiliation(s)
- Gaku Arakawa
- Insect-mimetics Research Unit, National Institute of Agrobiological Sciences
| | - Kei Kamino
- Biological Resource Center, National Institute of Technology and Evaluation
| | - Gaku Tokuda
- Tropical Biosphere Research Center, University of the Ryukyus
| | - Hirofumi Watanabe
- Insect-mimetics Research Unit, National Institute of Agrobiological Sciences
- Molecular Biomimetics Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization
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73
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Xia W, Bai Y, Cui Y, Xu X, Qian L, Shi P, Zhang W, Luo H, Zhan X, Yao B. Functional diversity of family 3 β-glucosidases from thermophilic cellulolytic fungus Humicola insolens Y1. Sci Rep 2016; 6:27062. [PMID: 27271847 PMCID: PMC4897640 DOI: 10.1038/srep27062] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 05/09/2016] [Indexed: 11/09/2022] Open
Abstract
The fungus Humicola insolens is one of the most powerful decomposers of crystalline cellulose. However, studies on the β-glucosidases from this fungus remain insufficient, especially on glycosyl hydrolase family 3 enzymes. In the present study, we analyzed the functional diversity of three distant family 3 β-glucosidases from Humicola insolens strain Y1, which belonged to different evolutionary clades, by heterogeneous expression in Pichia pastoris strain GS115. The recombinant enzymes shared similar enzymatic properties including thermophilic and neutral optima (50-60 °C and pH 5.5-6.0) and high glucose tolerance, but differed in substrate specificities and kinetics. HiBgl3B was solely active towards aryl β-glucosides while HiBgl3A and HiBgl3C showed broad substrate specificities including both disaccharides and aryl β-glucosides. Of the three enzymes, HiBgl3C exhibited the highest specific activity (158.8 U/mg on pNPG and 56.4 U/mg on cellobiose) and catalytic efficiency and had the capacity to promote cellulose degradation. Substitutions of three key residues Ile48, Ile278 and Thr484 of HiBgl3B to the corresponding residues of HiBgl3A conferred the enzyme activity towards sophorose, and vice versa. This study reveals the functional diversity of GH3 β-glucosidases as well as the key residues in recognizing +1 subsite of different substrates.
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Affiliation(s)
- Wei Xia
- College of Animal Science, Zhejiang University, Hangzhou 310058, People's Republic of China.,Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Yingguo Bai
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Ying Cui
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Xinxin Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Lichun Qian
- College of Animal Science, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Pengjun Shi
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Wei Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Huiying Luo
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
| | - Xiuan Zhan
- College of Animal Science, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Bin Yao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
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Singh G, Verma AK, Kumar V. Catalytic properties, functional attributes and industrial applications of β-glucosidases. 3 Biotech 2016; 6:3. [PMID: 28330074 PMCID: PMC4697909 DOI: 10.1007/s13205-015-0328-z] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/19/2015] [Indexed: 12/18/2022] Open
Abstract
β-Glucosidases are diverse group of enzymes with great functional importance to biological systems. These are grouped in multiple glycoside hydrolase families based on their catalytic and sequence characteristics. Most studies carried out on β-glucosidases are focused on their industrial applications rather than their endogenous function in the target organisms. β-Glucosidases performed many functions in bacteria as they are components of large complexes called cellulosomes and are responsible for the hydrolysis of short chain oligosaccharides and cellobiose. In plants, β-glucosidases are involved in processes like formation of required intermediates for cell wall lignification, degradation of endosperm’s cell wall during germination and in plant defense against biotic stresses. Mammalian β-glucosidases are thought to play roles in metabolism of glycolipids and dietary glucosides, and signaling functions. These enzymes have diverse biotechnological applications in food, surfactant, biofuel, and agricultural industries. The search for novel and improved β-glucosidase is still continued to fulfills demand of an industrially suitable enzyme. In this review, a comprehensive overview on detailed functional roles of β-glucosidases in different organisms, their industrial applications, and recent cloning and expression studies with biochemical characterization of such enzymes is presented for the better understanding and efficient use of diverse β-glucosidases.
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Affiliation(s)
- Gopal Singh
- Institute of Himalayan Bioresource Technology, Palampur, 176062, India
| | - A K Verma
- Department of Biochemistry, College of Basic Sciences and Humanities, G. B. Pant University of Agriculture and Technology, Pantnagar, 263145, India
| | - Vinod Kumar
- Department of Biotechnology, Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour, 173101, India.
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75
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Sinha SK, Datta S. β-Glucosidase from the hyperthermophilic archaeon Thermococcus sp. is a salt-tolerant enzyme that is stabilized by its reaction product glucose. Appl Microbiol Biotechnol 2016; 100:8399-409. [DOI: 10.1007/s00253-016-7601-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/25/2016] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
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76
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Goswami S, Gupta N, Datta S. Using the β-glucosidase catalyzed reaction product glucose to improve the ionic liquid tolerance of β-glucosidases. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:72. [PMID: 27006691 PMCID: PMC4802596 DOI: 10.1186/s13068-016-0484-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/10/2016] [Indexed: 05/25/2023]
Abstract
BACKGROUND Pretreating biomass with ionic liquids (IL) increases enzyme accessibility and cellulose is typically recovered through precipitation with an anti-solvent. An industrially feasible pretreatment and hydrolysis process requires robust cellulases that are stable and active in the presence of either small amounts of ILs co-precipitated with recovered cellulose or for saccharifications in the presence of IL. β-glucosidase (BG) hydrolyzes cellobiose into two molecules of glucose (Glc) and is the last step of biomass hydrolysis. These enzymes are prone not only to product inhibition by glucose but also to inactivation by ILs. With increasing interest in IL-based pretreatment methods, there is increasing focus toward a search for Glc-tolerant and IL-tolerant BG. RESULTS We identified a BG belonging to the GH1 family, H0HC94, encoded in Agrobacterium tumefaciens 5A, and cloned and overexpressed the protein in Escherichia coli. H0HC94 exhibited high enzymatic activity with β-glycosidic substrates (248 µmol/min/mg on pNPGlc and 262 µmol/min/mg on cellobiose) and tolerant to Glc (apparent K i = 686 mM). Further evidence of Glc-based stabilization came from the increase in melting temperature of H0HC94, with increasing Glc concentrations. The half-life of H0HC94 also increased between 2- and 20-fold in the presence of increasing concentrations of Glc. In the presence of 0.9 M of different [C2mim]-based ionic liquids, the specific activity of H0HC94 decreased by around 20-30 %. However, the addition of 100 mM glucose to the IL-enzyme mix resulted in a more stable enzyme as evidenced by the slight recovery of H0HC94 melting temperature and up to tenfold increase in half-life. This higher stability came at a cost of 2-10 % decrease in specific activity. The steady-state kinetic analyses for a subset of the ionic liquids tested indicate that the enzyme undergoes uncompetitive inhibition by glucose and ionic liquid, indicating the possibility of binding of the ionic liquid and glucose to the enzyme-substrate complex. CONCLUSIONS H0HC94 is a Glc-stabilized BG that is also tolerant up to 0.9 M concentrations of different IL's and indicates the possibilities of using an IL-Glc-based cellulose solvent that displays enzyme-compatibility.
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Affiliation(s)
- Shubhasish Goswami
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 India
| | - Neha Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 India
| | - Supratim Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 India
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Conversion of levoglucosan and cellobiosan by Pseudomonas putida KT2440. Metab Eng Commun 2016; 3:24-29. [PMID: 29468111 PMCID: PMC5779712 DOI: 10.1016/j.meteno.2016.01.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/08/2016] [Accepted: 01/30/2016] [Indexed: 11/23/2022] Open
Abstract
Pyrolysis offers a straightforward approach for the deconstruction of plant cell wall polymers into bio-oil. Recently, there has been substantial interest in bio-oil fractionation and subsequent use of biological approaches to selectively upgrade some of the resulting fractions. A fraction of particular interest for biological upgrading consists of polysaccharide-derived substrates including sugars and sugar dehydration products such as levoglucosan and cellobiosan, which are two of the most abundant pyrolysis products of cellulose. Levoglucosan can be converted to glucose-6-phosphate through the use of a levoglucosan kinase (LGK), but to date, the mechanism for cellobiosan utilization has not been demonstrated. Here, we engineer the microbe Pseudomonas putida KT2440 to use levoglucosan as a sole carbon and energy source through LGK integration. Moreover, we demonstrate that cellobiosan can be enzymatically converted to levoglucosan and glucose with β-glucosidase enzymes from both Glycoside Hydrolase Family 1 and Family 3. β-glucosidases are commonly used in both natural and industrial cellulase cocktails to convert cellobiose to glucose to relieve cellulase product inhibition and to facilitate microbial uptake of glucose. Using an exogenous β-glucosidase, we demonstrate that the engineered strain of P. putida can grow on levoglucosan up to 60 g/L and can also utilize cellobiosan. Overall, this study elucidates the biological pathway to co-utilize levoglucosan and cellobiosan, which will be a key transformation for the biological upgrading of pyrolysis-derived substrates. Levoglucosan kinase is engineered into Pseudomonas putida KT2440. Cellobiosan can be cleaved to levoglucosan and glucose by β-glucosidases. This provides a path forward to co-utilize levoglucosan and cellobiosan. These transformations will be important for hybrid processing applications.
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78
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Akram F, Haq IU, Khan MA, Hussain Z, Mukhtar H, Iqbal K. Cloning with kinetic and thermodynamic insight of a novel hyperthermostable β-glucosidase from Thermotoga naphthophila RKU-10T with excellent glucose tolerance. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2015.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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79
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Guo B, Amano Y, Nozaki K. Improvements in Glucose Sensitivity and Stability of Trichoderma reesei β-Glucosidase Using Site-Directed Mutagenesis. PLoS One 2016; 11:e0147301. [PMID: 26790148 PMCID: PMC4720395 DOI: 10.1371/journal.pone.0147301] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 01/02/2016] [Indexed: 01/07/2023] Open
Abstract
Glucose sensitivity and pH and thermal stabilities of Trichoderma reesei Cel1A (Bgl II) were improved by site-directed mutagenesis of only two amino acid residues (L167W or P172L) at the entrance of the active site. The Cel1A mutant showed high glucose tolerance (50% of inhibitory concentration = 650 mM), glucose stimulation (2.0 fold at 50 mM glucose), and enhanced specific activity (2.4-fold) compared with those of the wild-type Cel1A. Furthermore, the mutant enzyme showed stability at a wide pH range of 4.5–9.0 and possessed high thermal stability up to 50°C with 80% of the residual activities compared with the stability seen at the pH range of 6.5–7.0 and temperatures of up to 40°C in the wild-type Cel1A. Kinetic studies for hydrolysis revealed that the Cel1A mutant was competitively inhibited by glucose at similar levels as the wild-type enzyme. Additionally, the mutant enzyme exhibited substrate inhibition, which gradually disappeared with an increasing glucose concentration. These data suggest that the glucose stimulation was caused by relieve the substrate inhibition in the presence of glucose. To conclude, all the properties improved by the mutagenesis would be great advantages in degradation of cellulosic biomass together with cellulases.
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Affiliation(s)
- Boyang Guo
- Department of Bioscience and Textile Technology, Interdisciplinary Graduate School of Science and Technology, Shinshu University, Nagano, Japan
| | - Yoshihiko Amano
- Department of Bioscience and Textile Technology, Interdisciplinary Graduate School of Science and Technology, Shinshu University, Nagano, Japan
| | - Kouichi Nozaki
- Department of Bioscience and Textile Technology, Interdisciplinary Graduate School of Science and Technology, Shinshu University, Nagano, Japan
- * E-mail:
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80
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Niu H, Shah N, Kontoravdi C. Modelling of amorphous cellulose depolymerisation by cellulases, parametric studies and optimisation. Biochem Eng J 2016; 105:455-472. [PMID: 26865832 PMCID: PMC4705870 DOI: 10.1016/j.bej.2015.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A mechanistic model for heterogeneous cellulose hydrolysis by cellulases. A modeling framework for uncertainty analysis, model reduction and refinement. The parameters were estimated. Composition of cellulases cocktail was optimized using the model.
Improved understanding of heterogeneous cellulose hydrolysis by cellulases is the basis for optimising enzymatic catalysis-based cellulosic biorefineries. A detailed mechanistic model is developed to describe the dynamic adsorption/desorption and synergistic chain-end scissions of cellulases (endoglucanase, exoglucanase, and β-glucosidase) upon amorphous cellulose. The model can predict evolutions of the chain lengths of insoluble cellulose polymers and production of soluble sugars during hydrolysis. Simultaneously, a modelling framework for uncertainty analysis is built based on a quasi-Monte-Carlo method and global sensitivity analysis, which can systematically identify key parameters, help refine the model and improve its identifiability. The model, initially comprising 27 parameters, is found to be over-parameterized with structural and practical identification problems under usual operating conditions (low enzyme loadings). The parameter estimation problem is therefore mathematically ill posed. The framework allows us, on the one hand, to identify a subset of 13 crucial parameters, of which more accurate confidence intervals are estimated using a given experimental dataset, and, on the other hand, to overcome the identification problems. The model’s predictive capability is checked against an independent set of experimental data. Finally, the optimal composition of cellulases cocktail is obtained by model-based optimisation both for enzymatic hydrolysis and for the process of simultaneous saccharification and fermentation.
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Affiliation(s)
- Hongxing Niu
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK
| | - Nilay Shah
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK
| | - Cleo Kontoravdi
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK
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Xia W, Xu X, Qian L, Shi P, Bai Y, Luo H, Ma R, Yao B. Engineering a highly active thermophilic β-glucosidase to enhance its pH stability and saccharification performance. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:147. [PMID: 27446236 PMCID: PMC4955127 DOI: 10.1186/s13068-016-0560-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/11/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND β-Glucosidase is an important member of the biomass-degrading enzyme system, and plays vital roles in enzymatic saccharification for biofuels production. Candidates with high activity and great stability over high temperature and varied pHs are always preferred in industrial practice. To achieve cost-effective biomass conversion, exploring natural enzymes, developing high level expression systems and engineering superior mutants are effective approaches commonly used. RESULTS A newly identified β-glucosidase of GH3, Bgl3A, from Talaromyces leycettanus JCM12802, was overexpressed in yeast strain Pichia pastoris GS115, yielding a crude enzyme activity of 6000 U/ml in a 3 L fermentation tank. The purified enzyme exhibited outstanding enzymatic properties, including favorable temperature and pH optima (75 °C and pH 4.5), good thermostability (maintaining stable at 60 °C), and high catalytic performance (with a specific activity and catalytic efficiency of 905 U/mg and 9096/s/mM on pNPG, respectively). However, the narrow stability of Bgl3A at pH 4.0-5.0 would limit its industrial applications. Further site-directed mutagenesis indicated the role of excessive O-glycosylation in pH liability. By removing the potential O-glycosylation sites, two mutants showed improved pH stability over a broader pH range (3.0-10.0). Besides, with better stability under pH 5.0 and 50 °C compared with wild type Bgl3A, saccharification efficiency of mutant M1 was improved substantially cooperating with cellulase Celluclast 1.5L. And mutant M1 reached approximately equivalent saccharification performance to commercial β-glucosidase Novozyme 188 with identical β-glucosidase activity, suggesting its great prospect in biofuels production. CONCLUSIONS In this study, we overexpressed a novel β-glucosidase Bgl3A with high specific activity and high catalytic efficiency in P. pastoris. We further proved the negative effect of excessive O-glycosylation on the pH stability of Bgl3A, and enhanced the pH stability by reducing the O-glycosylation. And the enhanced mutants showed much better application prospect with substantially improved saccharification efficiency on cellulosic materials.
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Affiliation(s)
- Wei Xia
- />Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081 People’s Republic of China
- />College of Animal Science, Zhejiang University, Hangzhou, 310058 People’s Republic of China
| | - Xinxin Xu
- />Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 People’s Republic of China
| | - Lichun Qian
- />College of Animal Science, Zhejiang University, Hangzhou, 310058 People’s Republic of China
| | - Pengjun Shi
- />Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081 People’s Republic of China
| | - Yingguo Bai
- />Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081 People’s Republic of China
| | - Huiying Luo
- />Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081 People’s Republic of China
| | - Rui Ma
- />Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081 People’s Republic of China
| | - Bin Yao
- />Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081 People’s Republic of China
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82
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Santos CA, Zanphorlin LM, Crucello A, Tonoli CCC, Ruller R, Horta MAC, Murakami MT, de Souza AP. Crystal structure and biochemical characterization of the recombinant ThBgl, a GH1 β-glucosidase overexpressed in Trichoderma harzianum under biomass degradation conditions. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:71. [PMID: 27006690 PMCID: PMC4802607 DOI: 10.1186/s13068-016-0487-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 03/14/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND The conversion of biomass-derived sugars via enzymatic hydrolysis for biofuel production is a challenge. Therefore, the search for microorganisms and key enzymes that increase the efficiency of the saccharification of cellulosic substrates remains an important and high-priority area of study. Trichoderma harzianum is an important fungus known for producing high levels of cellulolytic enzymes that can be used for cellulosic ethanol production. In this context, β-glucosidases, which act synergistically with cellobiohydrolases and endo-β-1,4-glucanases in the saccharification process, are potential biocatalysts for the conversion of plant biomass to free glucose residues. RESULTS In the present study, we used RNA-Seq and genomic data to identify the major β-glucosidase expressed by T. harzianum under biomass degradation conditions. We mapped and quantified the expression of all of the β-glucosidases from glycoside hydrolase families 1 and 3, and we identified the enzyme with the highest expression under these conditions. The target gene was cloned and heterologously expressed in Escherichia coli, and the recombinant protein (rThBgl) was purified with high yields. rThBgl was characterized using a comprehensive set of biochemical, spectroscopic, and hydrodynamic techniques. Finally, we determined the crystallographic structure of the recombinant protein at a resolution of 2.6 Å. CONCLUSIONS Using a rational approach, we investigated the biochemical characteristics and determined the three-dimensional protein structure of a β-glucosidase that is highly expressed by T. harzianum under biomass degradation conditions. The methodology described in this manuscript will be useful for the bio-prospection of key enzymes, including cellulases and other accessory enzymes, for the development and/or improvement of enzymatic cocktails designed to produce ethanol from plant biomass.
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Affiliation(s)
- Clelton A. Santos
- />Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP Brazil
| | - Letícia M. Zanphorlin
- />Laboratório Nacional de Ciência e Tecnologia do Bioetanol, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP Brazil
| | - Aline Crucello
- />Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP Brazil
| | - Celisa C. C. Tonoli
- />Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP Brazil
| | - Roberto Ruller
- />Laboratório Nacional de Ciência e Tecnologia do Bioetanol, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP Brazil
| | - Maria A. C. Horta
- />Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP Brazil
| | - Mario T. Murakami
- />Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP Brazil
| | - Anete Pereira de Souza
- />Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP Brazil
- />Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP Brazil
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83
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A Neurospora crassa ÿ-glucosidase with potential for lignocellulose hydrolysis shows strong glucose tolerance and stimulation by glucose and xylose. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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84
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Flannelly DF, Aoki TG, Aristilde L. Short-time dynamics of pH-dependent conformation and substrate binding in the active site of beta-glucosidases: A computational study. J Struct Biol 2015; 191:352-64. [PMID: 26160737 DOI: 10.1016/j.jsb.2015.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 06/17/2015] [Accepted: 07/03/2015] [Indexed: 12/25/2022]
Abstract
The complete degradation of cellulose to glucose is essential to carbon turnover in terrestrial ecosystems and to engineered biofuel production. A rate-limiting step in this pathway is catalyzed by beta-glucosidase (BG) enzymes, which convert cellulobiose into two glucose molecules. The activity of these enzymes has been shown to vary with solution pH. However, it is not well understood how pH influences the enzyme conformation required for catalytic action on the substrate. A structural understanding of this pH effect is important for predicting shifts in BG activity in bioreactors and environmental matrices, in addition to informing targeted protein engineering. Here we applied molecular dynamics simulations to explore conformational and substrate binding dynamics in two well-characterized BGs of bacterial (Clostridium cellulovorans) and fungal (Trichoderma reesei) origins as a function of pH. The enzymes were simulated in an explicit solvated environment, with NaCl as electrolytes, at their prominent ionization states obtained at pH 5, 6, 7, and 7.5. Our findings indicated that pH-dependent changes in the ionization states of non-catalytic residues localized outside of the immediate active site led to pH-dependent disruption of the active site conformation. This disruption interferes with favorable H-bonding interactions with catalytic residues required to initiate catalysis on the substrate. We also identified specific non-catalytic residues that are involved in stabilizing the substrate at the optimal pH for enzyme activity. The simulations further revealed the dynamics of water-bridging interactions both outside and inside the substrate binding cleft during structural changes in the enzyme-substrate complex. These findings provide new structural insights into the pH-dependent substrate binding specificity in BGs.
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Affiliation(s)
- David F Flannelly
- The Institute for Comparative and Environmental Toxicology, College of Agricultural and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Thalia G Aoki
- Department of Biological and Environmental Engineering, College of Agricultural and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Ludmilla Aristilde
- The Institute for Comparative and Environmental Toxicology, College of Agricultural and Life Sciences, Cornell University, Ithaca, NY 14853, USA; Department of Biological and Environmental Engineering, College of Agricultural and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
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85
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Expression of novel glucose tolerant β-glucosidase on cell surface by Rhodotorula glutinis isolate. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2015. [DOI: 10.1016/j.bcab.2015.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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86
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Payne CM, Knott BC, Mayes HB, Hansson H, Himmel ME, Sandgren M, Ståhlberg J, Beckham GT. Fungal Cellulases. Chem Rev 2015; 115:1308-448. [DOI: 10.1021/cr500351c] [Citation(s) in RCA: 533] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506, United States
| | - Brandon C. Knott
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
| | - Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henrik Hansson
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Mats Sandgren
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
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87
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Cao LC, Wang ZJ, Ren GH, Kong W, Li L, Xie W, Liu YH. Engineering a novel glucose-tolerant β-glucosidase as supplementation to enhance the hydrolysis of sugarcane bagasse at high glucose concentration. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:202. [PMID: 26628916 PMCID: PMC4666061 DOI: 10.1186/s13068-015-0383-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 11/16/2015] [Indexed: 05/02/2023]
Abstract
BACKGROUND Most β-glucosidases reported are sensitive to the end product (glucose), making it the rate limiting component of cellulase for efficient degradation of cellulose through enzymatic route. Thus, there are ongoing interests in searching for glucose-tolerant β-glucosidases, which are still active at high glucose concentration. Although many β-glucosidases with different glucose-tolerance levels have been isolated and characterized in the past decades, the effects of glucose-tolerance on the hydrolysis of cellulose are not thoroughly studied. RESULTS In the present study, a novel β-glucosidase (Bgl6) with the half maximal inhibitory concentration (IC 50) of 3.5 M glucose was isolated from a metagenomic library and characterized. However, its poor thermostability at 50 °C hindered the employment in cellulose hydrolysis. To improve its thermostability, random mutagenesis was performed. A thermostable mutant, M3, with three amino acid substitutions was obtained. The half-life of M3 at 50 °C is 48 h, while that of Bgl6 is 1 h. The K cat/K m value of M3 is 3-fold higher than that of Bgl6. The mutations maintained its high glucose-tolerance with IC 50 of 3.0 M for M3. In a 10-h hydrolysis of cellobiose, M3 completely converted cellobiose to glucose, while Bgl6 reached a conversion of 80 %. Then their synergistic effects with the commercial cellulase (Celluclast 1.5 L) on hydrolyzing pretreated sugarcane bagasse (SCB) were investigated. The supplementation of Bgl6 or mutant M3 to Celluclast 1.5 L significantly improved the SCB conversion from 64 % (Celluclast 1.5 L alone) to 79 % (Bgl6) and 94 % (M3), respectively. To further evaluate the application potential of M3 in high-solids cellulose hydrolysis, such reactions were performed at initial glucose concentration of 20-500 mM. Results showed that the supplementation of mutant M3 enhanced the glucose production from SCB under all the conditions tested, improving the SCB conversion by 14-35 %. CONCLUSIONS These results not only clearly revealed the significant role of glucose-tolerance in cellulose hydrolysis, but also showed that mutant M3 may be a potent candidate for high-solids cellulose refining.
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Affiliation(s)
- Li-chuang Cao
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Zhi-jun Wang
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Guang-hui Ren
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Wei Kong
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Liang Li
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Wei Xie
- />State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Yu-huan Liu
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
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88
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Bringing functions together with fusion enzymes—from nature’s inventions to biotechnological applications. Appl Microbiol Biotechnol 2014; 99:1545-56. [DOI: 10.1007/s00253-014-6315-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/04/2014] [Accepted: 12/09/2014] [Indexed: 12/18/2022]
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89
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Silveira RL, Skaf MS. Molecular Dynamics Simulations of Family 7 Cellobiohydrolase Mutants Aimed at Reducing Product Inhibition. J Phys Chem B 2014; 119:9295-303. [DOI: 10.1021/jp509911m] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Rodrigo L. Silveira
- Institute
of Chemistry, University of Campinas, Cx. P. 6154 Campinas, SP, 13084-862, Brazil
| | - Munir S. Skaf
- Institute
of Chemistry, University of Campinas, Cx. P. 6154 Campinas, SP, 13084-862, Brazil
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90
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Busk PK, Lange M, Pilgaard B, Lange L. Several genes encoding enzymes with the same activity are necessary for aerobic fungal degradation of cellulose in nature. PLoS One 2014; 9:e114138. [PMID: 25461894 PMCID: PMC4252092 DOI: 10.1371/journal.pone.0114138] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/03/2014] [Indexed: 12/30/2022] Open
Abstract
The cellulose-degrading fungal enzymes are glycoside hydrolases of the GH families and lytic polysaccharide monooxygenases. The entanglement of glycoside hydrolase families and functions makes it difficult to predict the enzymatic activity of glycoside hydrolases based on their sequence. In the present study we further developed the method Peptide Pattern Recognition to an automatic approach not only to find all genes encoding glycoside hydrolases and lytic polysaccharide monooxygenases in fungal genomes but also to predict the function of the genes. The functional annotation is an important feature as it provides a direct route to predict function from primary sequence. Furthermore, we used Peptide Pattern Recognition to compare the cellulose-degrading enzyme activities encoded by 39 fungal genomes. The results indicated that cellobiohydrolases and AA9 lytic polysaccharide monooxygenases are hallmarks of cellulose-degrading fungi except brown rot fungi. Furthermore, a high number of AA9, endocellulase and β-glucosidase genes were identified, not in what are known to be the strongest, specialized lignocellulose degraders but in saprophytic fungi that can use a wide variety of substrates whereas only few of these genes were found in fungi that have a limited number of natural, lignocellulotic substrates. This correlation suggests that enzymes with different properties are necessary for degradation of cellulose in different complex substrates. Interestingly, clustering of the fungi based on their predicted enzymes indicated that Ascomycota and Basidiomycota use the same enzymatic activities to degrade plant cell walls.
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Affiliation(s)
- Peter K. Busk
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
- * E-mail:
| | - Mette Lange
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
| | - Bo Pilgaard
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
| | - Lene Lange
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
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91
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A Novel β-Glucosidase from Humicola insolens with High Potential for Untreated Waste Paper Conversion to Sugars. Appl Biochem Biotechnol 2014; 173:391-408. [DOI: 10.1007/s12010-014-0847-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 03/03/2014] [Indexed: 11/26/2022]
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92
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Biver S, Stroobants A, Portetelle D, Vandenbol M. Two promising alkaline β-glucosidases isolated by functional metagenomics from agricultural soil, including one showing high tolerance towards harsh detergents, oxidants and glucose. ACTA ACUST UNITED AC 2014; 41:479-88. [DOI: 10.1007/s10295-014-1400-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/01/2014] [Indexed: 01/07/2023]
Abstract
Abstract
New β-glucosidase activities were identified by screening metagenomic libraries constructed with DNA isolated from the topsoil of a winter wheat field. Two of the corresponding proteins, displaying an unusual preference for alkaline conditions, were selected for purification by Ni-NTA chromatography. AS-Esc6, a 762-amino-acid enzyme belonging to glycoside hydrolase family 3, proved to be a mesophilic aryl-β-glucosidase with maximal activity around pH 8 and 40 °C. A similar pH optimum was found for AS-Esc10, a 475-amino-acid GH1-family enzyme, but this enzyme remained significantly active across a wider pH range and was also markedly more stable than AS-Esc6 at pH greater than 10. AS-Esc10 was found to degrade cellobiose and diverse aryl glycosides, with an optimal temperature of 60 °C and good stability up to 50 °C. Unlike AS-Esc6, which showed a classically low inhibitory constant for glucose (14 mM), AS-Esc10 showed enhanced activity in the presence of molar concentrations of glucose. AS-Esc10 was highly tolerant to hydrogen peroxide and also to sodium dodecyl sulfate, this being indicative of kinetic stability. This unique combination of properties makes AS-Esc10 a particularly promising candidate whose potential in biotechnological applications is worth exploring further.
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Affiliation(s)
- Sophie Biver
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
| | - Aurore Stroobants
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
| | - Daniel Portetelle
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
| | - Micheline Vandenbol
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
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