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Boudabbous M, Ben Hmad I, Zaidi M, Saibi W, Jlaiel L, Gargouri A. Biosynthesis and one-step enrichment process of potentially prebiotic cello-oligosaccharides produced by β-glucosidase from Fusarium solani. Arch Microbiol 2024; 206:395. [PMID: 39249579 DOI: 10.1007/s00203-024-04111-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 08/14/2024] [Indexed: 09/10/2024]
Abstract
Cello-oligosaccharides (COS) become a new type of functional oligosaccharides. COS transglycosylation reactions were studied to enhance COS yield production. Seeking the ability of the free form of Fusarium solani β-glucosidase (FBgl1) to synthesize COS under low substrate concentrations, we found out that this biocatalyst initiates this reaction with only 1 g/L of cellobiose, giving rise to the formation of cellotriose. Cellotriose and cellopentaose were detected in biphasic conditions with an immobilized FBgl1 and when increased to 50 g/L of cellobiose as a starter concentration. After the biocatalyst recycling process, the trans-glycosylation yield of COS was maintained after 5 cycles, and the COS concentration was 6.70 ± 0.35 g/L. The crude COS contained 20.15 ± 0.25 g/L glucose, 23.15 ± 0.22 g/L non-reacting substrate cellobiose, 5.25 ± 0.53 g/L, cellotriose and 1.49 ± 0.32 g/L cellopentaose. A bioprocess was developed for cellotriose enrichment, using whole Bacillus velezensis cells as a microbial purification tool. This bacteria consumed glucose, unreacted cellobiose, and cellopentaose while preserving cellotriose in the fermented medium. This study provides an excellent enzyme candidate for industrial COS production and is also the first study on the single-step COS enrichment process.
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Affiliation(s)
- Manel Boudabbous
- Laboratory of Molecular Biotechnology of Eukaryotes, Center of Biotechnology of Sfax (CBS), University of Sfax, Sfax, Tunisia.
| | - Ines Ben Hmad
- Laboratory of Molecular Biotechnology of Eukaryotes, Center of Biotechnology of Sfax (CBS), University of Sfax, Sfax, Tunisia
| | - Mariem Zaidi
- Laboratory of Molecular Biotechnology of Eukaryotes, Center of Biotechnology of Sfax (CBS), University of Sfax, Sfax, Tunisia
| | - Walid Saibi
- Laboratory of Biotechnology and Plant Improvement, Centre of Biotechnology of Sfax (CBS), University of Sfax, Sfax, Tunisia
| | - Lobna Jlaiel
- Analytical Service Unit, Center of Biotechnology of Sfax (CBS), University of Sfax, Sfax, Tunisia
| | - Ali Gargouri
- Laboratory of Molecular Biotechnology of Eukaryotes, Center of Biotechnology of Sfax (CBS), University of Sfax, Sfax, Tunisia
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2
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Pitchayatanakorn P, Suwan E, Kongsaeree PT. Characterization of BrGH3A, a bovine rumen-derived glycoside hydrolase family 3 β-glucosidase with a permuted domain arrangement. PLoS One 2024; 19:e0305817. [PMID: 38980877 PMCID: PMC11233000 DOI: 10.1371/journal.pone.0305817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 06/05/2024] [Indexed: 07/11/2024] Open
Abstract
The bovine rumen contains a large consortium of residential microbes that release a variety of digestive enzymes for feed degradation. However, the utilization of these microbial enzymes is still limited because these rumen microorganisms are mostly anaerobes and are thus unculturable. Therefore, we applied a sequence-based metagenomic approach to identify a novel 2,445-bp glycoside hydrolase family 3 β-glucosidase gene known as BrGH3A from the metagenome of bovine ruminal fluid. BrGH3A β-glucosidase is a 92-kDa polypeptide composed of 814 amino acid residues. Unlike most glycoside hydrolases in the same family, BrGH3A exhibited a permuted domain arrangement consisting of an (α/β)6 sandwich domain, a fibronectin type III domain and a (β/α)8 barrel domain. BrGH3A exhibited greater catalytic efficiency toward laminaribiose than cellobiose. We proposed that BrGH3A is an exo-acting β-glucosidase from Spirochaetales bacteria that is possibly involved in the intracellular degradation of β-1,3-/1,4-mixed linkage glucans that are present in grass cell walls. BrGH3A exhibits rich diversity in rumen hydrolytic enzymes and may represent a member of a new clan with a permuted domain topology within the large family.
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Affiliation(s)
| | - Eukote Suwan
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
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Erkanli ME, El-Halabi K, Kim JR. Exploring the diversity of β-glucosidase: Classification, catalytic mechanism, molecular characteristics, kinetic models, and applications. Enzyme Microb Technol 2024; 173:110363. [PMID: 38041879 DOI: 10.1016/j.enzmictec.2023.110363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 12/04/2023]
Abstract
High-value chemicals and energy-related products can be produced from biomass. Biorefinery technology offers a sustainable and cost-effective method for this high-value conversion. β-glucosidase is one of the key enzymes in biorefinery processes, catalyzing the production of glucose from aryl-glycosides and cello-oligosaccharides via the hydrolysis of β-glycosidic bonds. Although β-glucosidase plays a critical catalytic role in the utilization of cellulosic biomass, its efficacy is often limited by substrate or product inhibitions, low thermostability, and/or insufficient catalytic activity. To provide a detailed overview of β-glucosidases and their benefits in certain desired applications, we collected and summarized extensive information from literature and public databases, covering β-glucosidases in different glycosidase hydrolase families and biological kingdoms. These β-glucosidases show differences in amino acid sequence, which are translated into varying degrees of the molecular properties critical in enzymatic applications. This review describes studies on the diversity of β-glucosidases related to the classification, catalytic mechanisms, key molecular characteristics, kinetics models, and applications, and highlights several β-glucosidases displaying high stability, activity, and resistance to glucose inhibition suitable for desired biotechnological applications.
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Affiliation(s)
- Mehmet Emre Erkanli
- Department of Chemical and Biomolecular Engineering, New York University, 6 MetroTech Center, Brooklyn, NY 11201, United States
| | - Khalid El-Halabi
- Department of Chemical and Biomolecular Engineering, New York University, 6 MetroTech Center, Brooklyn, NY 11201, United States
| | - Jin Ryoun Kim
- Department of Chemical and Biomolecular Engineering, New York University, 6 MetroTech Center, Brooklyn, NY 11201, United States.
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Besada-Lombana PB, Chen W, Da Silva NA. An extracellular glucose sensor for substrate-dependent secretion and display of cellulose-degrading enzymes. Biotechnol Bioeng 2024; 121:403-408. [PMID: 37749915 DOI: 10.1002/bit.28549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/17/2023] [Accepted: 08/30/2023] [Indexed: 09/27/2023]
Abstract
The efficient hydrolysis of lignocellulosic biomass into fermentable sugars is key for viable economic production of biofuels and biorenewable chemicals from second-generation feedstocks. Consolidated bioprocessing (CBP) combines lignocellulose saccharification and chemical production in a single step. To avoid wasting valuable resources during CBP, the selective secretion of enzymes (independent or attached to the surface) based on the carbon source available is advantageous. To enable enzyme expression and secretion based on extracellular glucose levels, we implemented a G-protein-coupled receptor (GPCR)-based extracellular glucose sensor; this allows the secretion and display of cellulases in the presence of the cellulosic fraction of lignocellulose by leveraging cellobiose-dependent signal amplification. We focused on the glucose-responsiveness of the HXT1 promoter and engineered PHXT1 by changing its core to that of the strong promoter PTHD3 , increasing extracellular enzyme activity by 81%. We then demonstrated glucose-mediated expression and cell-surface display of the β-glucosidase BglI on the surface of Saccharomyces cerevisiae. The display system was further optimized by re-directing fatty acid pools from lipid droplet synthesis toward formation of membrane precursors via knock-out of PAH1. This resulted in an up to 4.2-fold improvement with respect to the baseline strain. Finally, we observed cellobiose-dependent signal amplification of the system with an increase in enzymatic activity of up to 3.1-fold when cellobiose was added.
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Affiliation(s)
- Pamela B Besada-Lombana
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California, USA
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Nancy A Da Silva
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California, USA
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5
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Zhou HY, Chen Q, Zhang YF, Chen DD, Yi XN, Chen DS, Cheng XP, Li M, Wang HY, Chen KQ, Liu ZQ, Zheng YG. Improving the catalytic activity of β-glucosidase from Coniophora puteana via semi-rational design for efficient biomass cellulose degradation. Enzyme Microb Technol 2023; 164:110188. [PMID: 36584665 DOI: 10.1016/j.enzmictec.2022.110188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
In order to improve the degradation activity of β-glucosidase (CpBgl) from Coniophora puteana, the structural modification was conducted. The enzyme activity of mutants CpBgl-Q20C and CpBgl-A240S was increased by 65.75% and 58.58%, respectively. These mutants exhibited maximum activity under the same conditions as wild-type CpBgl (65 ℃ and pH 5.0), slightly improved stabilities compared that of the wild-type, and remarkably enhanced activities in the presence of Mn2+ or Fe2+. The Vmax of CpBgl-Q20C and CpBgl-A240S was increased to 138.18 and 125.14 μmol/mg/min, respectively, from 81.34 μmol/mg/min of the wild-type, and the catalysis efficiency (kcat/Km) of CpBgl-Q20C (335.79 min-1/mM) and CpBgl-A240S (281.51 min-1/mM) was significantly improved compared with that of the wild-type (149.12 min-1/mM). When the mutant CpBgl-Q20C were used in the practical degradation of different biomasses, the glucose yields of filter paper, corncob residue, and fungi mycelia residue were increased by 17.68%, 25.10%, and 20.37%, respectively. The spatial locations of the mutation residues in the architecture of CpBgl and their unique roles in the enzyme-substrate binding and catalytic efficiency were probed in this work. These results laid a foundation for evolution of other glycoside hydrolases and the industrial bio-degradation of cellulosic biomass in nature.
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Affiliation(s)
- Hai-Yan Zhou
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - Qi Chen
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - Yi-Feng Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - Dou-Dou Chen
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - Xiao-Nan Yi
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - De-Shui Chen
- Zhejiang Huakang Pharmaceutical Co., LTD., 18 Huagong Road, Huabu Town, Kaihua 324302, People's Republic of China
| | - Xin-Ping Cheng
- Zhejiang Huakang Pharmaceutical Co., LTD., 18 Huagong Road, Huabu Town, Kaihua 324302, People's Republic of China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., LTD., 18 Huagong Road, Huabu Town, Kaihua 324302, People's Republic of China
| | - Hong-Yan Wang
- Zhejiang Huakang Pharmaceutical Co., LTD., 18 Huagong Road, Huabu Town, Kaihua 324302, People's Republic of China
| | - Kai-Qian Chen
- Zhejiang Huakang Pharmaceutical Co., LTD., 18 Huagong Road, Huabu Town, Kaihua 324302, People's Republic of China
| | - Zhi-Qiang Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China.
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
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Zhang X, Chen X, Li S, Bello A, Liu J, Gao L, Fan Z, Wang S, Liu L, Ma B, Li H. Mechanism of differential expression of β-glucosidase genes in functional microbial communities in response to carbon catabolite repression. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:3. [PMID: 35418139 PMCID: PMC8756671 DOI: 10.1186/s13068-021-02101-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 12/29/2021] [Indexed: 11/10/2022]
Abstract
Abstract
Background
β-Glucosidase is the rate-limiting enzyme of cellulose degradation. It has been stipulated and established that β-glucosidase-producing microbial communities differentially regulate the expression of glucose/non-glucose tolerant β-glucosidase genes. However, it is still unknown if this differential expression of functional microbial community happens accidentally or as a general regulatory mechanism, and of what biological significance it has. To investigate the composition and function of microbial communities and how they respond to different carbon metabolism pressures and the transcriptional regulation of functional genes, the different carbon metabolism pressure was constructed by setting up the static chamber during composting.
Results
The composition and function of functional microbial communities demonstrated different behaviors under the carbon metabolism pressure. Functional microbial community up-regulated glucose tolerant β-glucosidase genes expression to maintain the carbon metabolism rate by enhancing the transglycosylation activity of β-glucosidase to compensate for the decrease of hydrolysis activity under carbon catabolite repression (CCR). Micrococcales play a vital role in the resistance of functional microbial community under CCR. The transcription regulation of GH1 family β-glucosidase genes from Proteobacteria showed more obvious inhibition than other phyla under CCR.
Conclusion
Microbial functional communities differentially regulate the expression of glucose/non-glucose tolerant β-glucosidase genes under CCR, which is a general regulatory mechanism, not accidental. Furthermore, the differentially expressed β-glucosidase gene exhibited species characteristics at the phylogenetic level.
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7
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Fernandes CG, Sawant SC, Mule TA, Khadye VS, Lali AM, Odaneth AA. Enhancing cellulases through synergistic β-glucosidases for intensifying cellulose hydrolysis. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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He Y, Wang C, Jiao R, Ni Q, Wang Y, Gao Q, Zhang Y, Xu G. Biochemical characterization of a novel glucose-tolerant GH3 β-glucosidase (Bgl1973) from Leifsonia sp. ZF2019. Appl Microbiol Biotechnol 2022; 106:5063-5079. [PMID: 35833950 DOI: 10.1007/s00253-022-12064-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/27/2022] [Accepted: 07/02/2022] [Indexed: 11/25/2022]
Abstract
Beta-glucosidase (Bgl) is an enzyme with considerable food, beverage, and biofuel processing potential. However, as many Bgls are inhibited by their reaction end product glucose, their industrial applications are greatly limited. In this study, a novel Bgl gene (Bgl1973) was cloned from Leifsonia sp. ZF2019 and heterologously expressed in E. coli. Sequence analysis and structure modeling revealed that Bgl1973 was 748 aa, giving it a molecular weight of 78 kDa, and it showed high similarity with the glycoside hydrolase 3 (GH3) family Bgls with which its active site residues were conserved. By using pNPGlc (p-nitrophenyl-β-D-glucopyranoside) as substrate, the optimum temperature and pH of Bgl1973 were shown to be 50 °C and 7.0, respectively. Bgl1973 was insensitive to most metal ions (12.5 mM), 1% urea, and even 0.1% Tween-80. This enzyme maintained 60% of its original activity in the presence of 20% NaCl, demonstrating its excellent salt tolerance. Furthermore, it still had 83% residual activity in 1 M of glucose, displaying its outstanding glucose tolerance. The Km, Vmax, and kcat of Bgl1973 were 0.22 mM, 44.44 μmol/min mg, and 57.78 s-1, respectively. Bgl1973 had a high specific activity for pNPGlc (19.10 ± 0.59 U/mg) and salicin (20.43 ± 0.92 U/mg). Furthermore, molecular docking indicated that the glucose binding location and the narrow and deep active channel geometry might contribute to the glucose tolerance of Bgl1973. Our results lay a foundation for the studying of this glucose-tolerant β-glucosidase and its applications in many industrial settings. KEY POINTS: • A novel β-glucosidase from GH3 was obtained from Leifsonia sp. ZF2019. • Bgl1973 demonstrated excellent glucose tolerance. • The glucose tolerance of Bgl1973 was explained using molecular docking analysis.
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Affiliation(s)
- Yi He
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Chenxi Wang
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Ronghu Jiao
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Qinxue Ni
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Yan Wang
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Qianxin Gao
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Youzuo Zhang
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Guangzhi Xu
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China.
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Méndez-Líter JA, Pozo-Rodríguez A, Madruga E, Rubert M, Santana AG, de Eugenio LI, Sánchez C, Martínez A, Prieto A, Martínez MJ. Glycosylation of Epigallocatechin Gallate by Engineered Glycoside Hydrolases from Talaromyces amestolkiae: Potential Antiproliferative and Neuroprotective Effect of These Molecules. Antioxidants (Basel) 2022; 11:antiox11071325. [PMID: 35883816 PMCID: PMC9312355 DOI: 10.3390/antiox11071325] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/24/2022] [Accepted: 06/30/2022] [Indexed: 02/04/2023] Open
Abstract
Glycoside hydrolases (GHs) are enzymes that hydrolyze glycosidic bonds, but some of them can also catalyze the synthesis of glycosides by transglycosylation. However, the yields of this reaction are generally low since the glycosides formed end up being hydrolyzed by these same enzymes. For this reason, mutagenic variants with null or drastically reduced hydrolytic activity have been developed, thus enhancing their synthetic ability. Two mutagenic variants, a glycosynthase engineered from a β-glucosidase (BGL-1-E521G) and a thioglycoligase from a β-xylosidase (BxTW1-E495A), both from the ascomycete Talaromyces amestolkiae, were used to synthesize three novel epigallocatechin gallate (EGCG) glycosides. EGCG is a phenolic compound from green tea known for its antioxidant effects and therapeutic benefits, whose glycosylation could increase its bioavailability and improve its bioactive properties. The glycosynthase BGL-1-E521G produced a β-glucoside and a β-sophoroside of EGCG, while the thioglycoligase BxTW1-E495A formed the β-xyloside of EGCG. Glycosylation occurred in the 5″ and 4″ positions of EGCG, respectively. In this work, the reaction conditions for glycosides’ production were optimized, achieving around 90% conversion of EGCG with BGL-1-E521G and 60% with BxTW1-E495A. The glycosylation of EGCG caused a slight loss of its antioxidant capacity but notably increased its solubility (between 23 and 44 times) and, in the case of glucoside, also improved its thermal stability. All three glycosides showed better antiproliferative properties on breast adenocarcinoma cell line MDA-MB-231 than EGCG, and the glucosylated and sophorylated derivatives induced higher neuroprotection, increasing the viability of SH-S5Y5 neurons exposed to okadaic acid.
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Affiliation(s)
- Juan A. Méndez-Líter
- Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (J.A.M.-L.); (A.P.-R.); (L.I.d.E.); (A.P.)
| | - Ana Pozo-Rodríguez
- Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (J.A.M.-L.); (A.P.-R.); (L.I.d.E.); (A.P.)
| | - Enrique Madruga
- Centro de Investigaciones Biológicas Margarita Salas, Department of Structural and Chemical Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (E.M.); (A.M.)
| | - María Rubert
- Department of Biochemistry and Molecular Biology, School of Biology, Instituto de Investigación Hospital 12 de Octubre, Universidad Complutense de Madrid, C/de José Antonio Nováis 12, 28040 Madrid, Spain; (M.R.); (C.S.)
| | - Andrés G. Santana
- Department of Bioorganic Chemistry, Instituto de Química Orgánica General, Spanish National Research Council (CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain;
| | - Laura I. de Eugenio
- Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (J.A.M.-L.); (A.P.-R.); (L.I.d.E.); (A.P.)
| | - Cristina Sánchez
- Department of Biochemistry and Molecular Biology, School of Biology, Instituto de Investigación Hospital 12 de Octubre, Universidad Complutense de Madrid, C/de José Antonio Nováis 12, 28040 Madrid, Spain; (M.R.); (C.S.)
| | - Ana Martínez
- Centro de Investigaciones Biológicas Margarita Salas, Department of Structural and Chemical Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (E.M.); (A.M.)
| | - Alicia Prieto
- Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (J.A.M.-L.); (A.P.-R.); (L.I.d.E.); (A.P.)
| | - María Jesús Martínez
- Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain; (J.A.M.-L.); (A.P.-R.); (L.I.d.E.); (A.P.)
- Correspondence:
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10
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Enzymatic transglycosylation by the Ping Pong bi bi mechanism: Selectivity for transglycosylation versus primary and secondary hydrolysis. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Enzymatic glycosylation of menthol: optimization of synthesis and extraction processes using response surface methodology and biological evaluation of synthesized product. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02061-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Lee WH, Jin YS. Observation of Cellodextrin Accumulation Resulted from Non-Conventional Secretion of Intracellular β-Glucosidase by Engineered Saccharomyces cerevisiae Fermenting Cellobiose. J Microbiol Biotechnol 2021; 31:1035-1043. [PMID: 34226403 PMCID: PMC9705985 DOI: 10.4014/jmb.2105.05018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/30/2021] [Accepted: 07/05/2021] [Indexed: 12/15/2022]
Abstract
Although engineered Saccharomyces cerevisiae fermenting cellobiose is useful for the production of biofuels from cellulosic biomass, cellodextrin accumulation is one of the main problems reducing ethanol yield and productivity in cellobiose fermentation with S. cerevisiae expressing cellodextrin transporter (CDT) and intracellular β-glucosidase (GH1-1). In this study, we investigated the reason for the cellodextrin accumulation and how to alleviate its formation during cellobiose fermentation using engineered S. cerevisiae fermenting cellobiose. From the series of cellobiose fermentation using S. cerevisiae expressing only GH1-1 under several culture conditions, it was discovered that small amounts of GH1-1 were secreted and cellodextrin was generated through trans-glycosylation activity of the secreted GH1-1. As GH1-1 does not have a secretion signal peptide, non-conventional protein secretion might facilitate the secretion of GH1-1. In cellobiose fermentations with S. cerevisiae expressing only GH1-1, knockout of TLG2 gene involved in non-conventional protein secretion pathway significantly delayed cellodextrin formation by reducing the secretion of GH1-1 by more than 50%. However, in cellobiose fermentations with S. cerevisiae expressing both GH1-1 and CDT-1, TLG2 knockout did not show a significant effect on cellodextrin formation, although secretion of GH1-1 was reduced by more than 40%. These results suggest that the development of new intracellular β-glucosidase, not influenced by non-conventional protein secretion, is required for better cellobiose fermentation performances of engineered S. cerevisiae fermenting cellobiose.
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Affiliation(s)
- Won-Heong Lee
- Department of Food Science and Human Nutrition, and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA,Department of Bioenergy Science and Technology, and Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea,Corresponding author Phone: +82-62-530-2046 Fax: +82-62-530-2047 E-mail:
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Lee J, Kim S, Chung HY, Kang A, Kim S, Hwang H, Yang SI, Yun WS. Electrochemical microgap immunosensors for selective detection of pathogenic Aspergillus niger. JOURNAL OF HAZARDOUS MATERIALS 2021; 411:125069. [PMID: 33454571 DOI: 10.1016/j.jhazmat.2021.125069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/18/2020] [Accepted: 01/02/2021] [Indexed: 06/12/2023]
Abstract
Aspergillus niger (A. niger) is a well-known allergenic, harmful fungus in the indoor environment that can cause asthmatic symptoms and atopy. Previous immunosensing approach suffers from an insufficient detection limit, mainly because there are no techniques for target amplification. We report an electrochemical immunosensor that selectively quantifies the A. niger based on the detection of extracellular proteins by using a specific interaction with antibody. The sensor was designed to show a decrease in redox current upon binding of the antigens secreted from A. niger onto an antibody-immobilized surface between the interdigitated electrodes. The extracellular proteins were profiled by LC-MS/MS to identify the antigens existing in the A. niger solution. Since the targets of the sensor are the proteins, its sensitivity and selectivity remain almost intact even after filtration of the spores. It was also found that the use of secretion promoter in the sampling stage greatly improved the sensor's limit of detection (LOD) for the spores. By this, the LOD was lowered by a few orders of magnitude so as to reach the value as low as ~101 spores/mL.
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Affiliation(s)
- Jisu Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16429, Republic of Korea
| | - Semee Kim
- Department of Chemistry, Sungkyunkwan University, Suwon 16429, Republic of Korea
| | - Ha Young Chung
- Department of Applied Chemistry, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Aeyeon Kang
- Nano/Bio Fusion Technology Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seunghun Kim
- Department of Chemistry, Sungkyunkwan University, Suwon 16429, Republic of Korea
| | - Heeyoun Hwang
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Sung Ik Yang
- Department of Applied Chemistry, Kyung Hee University, Yongin 17104, Republic of Korea.
| | - Wan Soo Yun
- Department of Chemistry, Sungkyunkwan University, Suwon 16429, Republic of Korea; Nano/Bio Fusion Technology Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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Unconventional β-Glucosidases: A Promising Biocatalyst for Industrial Biotechnology. Appl Biochem Biotechnol 2021; 193:2993-3016. [PMID: 33871765 DOI: 10.1007/s12010-021-03568-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 04/08/2021] [Indexed: 10/21/2022]
Abstract
β-Glucosidases primarily catalyze removal of terminal glucosyl residues from a variety of glucoconjugates and also perform transglycosylation and reverse hydrolysis. These catalytic properties can be readily exploited for degradation of lignocellulosic biomass as well as for pharmaceutical, food and flavor industries. β-Glucosidases have been either isolated in the native form from the producer organism or recombinantly expressed and gaged for their biochemical properties and substrate specificities. Although almond and Aspergillus niger have been instantly recognizable sources of β-glucosidases utilized for various applications, an intricate pool of novel β-glucosidases from different sources can provide their potent replacements. Moreover, one can envisage the better efficacy of these novel candidates in biofuel and biorefinery industries facilitating efficient degradation of biomass. This article reviews properties of the novel β-glucosidases such as glucose tolerance and activation, substrate specificity, and thermostability which can be useful for their applications in lignocellulose degradation, food industry, and pharmaceutical industry in comparison with the β-glucosidases from the conventional sources. Such β-glucosidases have potential for encouraging white biotechnology.
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El-Ghonemy DH. Optimization of extracellular ethanol-tolerant β-glucosidase production from a newly isolated Aspergillus sp. DHE7 via solid state fermentation using jojoba meal as substrate: purification and biochemical characterization for biofuel preparation. J Genet Eng Biotechnol 2021; 19:45. [PMID: 33761018 PMCID: PMC7991022 DOI: 10.1186/s43141-021-00144-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/12/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND The increasing demand and the continuous depletion in fossil fuels have persuaded researchers to investigate new sources of renewable energy. Bioethanol produced from cellulose could be a cost-effective and a viable alternative to petroleum. It is worth note that β-glucosidase plays a key role in the hydrolysis of cellulose and therefore in the production of bioethanol. This study aims to investigate a simple and standardized method for maximization of extracellular β-glucosidase production from a novel fungal isolate under solid-state fermentation using agro-industrial residues as the sole source of carbon and nitrogen. Furthermore, purification and characterization of β-glucosidase were performed to determine the conditions under which the enzyme displayed the highest performance. RESULTS A fungus identified genetically as a new Aspergillus sp. DHE7 was found to exhibit the highest extracellular β-glucosidase production among the sixty fungal isolates tested. Optimization of culture conditions improved the enzyme biosynthesis by 2.1-fold (174.6 ± 5.8 U/g of dry substrate) when the fungus grown for 72 h at 35 °C on jojoba meal with 60% of initial substrate moisture, pH 6.0, and an inoculum size of 2.54 × 107 spores/mL. The enzyme was purified to homogeneity through a multi-step purification process. The purified β-glucosidase is monomeric with a molecular mass of 135 kDa as revealed by the SDS-PAGE analysis. Optimum activity was observed at 60 °C and pH of 6.0, with a remarkable pH and thermal stability. The enzyme retained about 79% and 53% of its activity, after 1 h at 70 °C and 80 °C, respectively. The purified β-glucosidase hydrolysed a wide range of substrates but displaying its greater activity on p-nitrophenyl-β-D-glucopyranoside and cellobiose. The values of Km and Vmax on p-nitrophenyl β-D-glucopyranoside were 0.4 mM and 232.6 U/mL, respectively. Purified β-glucosidase displayed high catalytic activity (improved by 25%) in solutions contained ethanol up to 15%. CONCLUSION β-glucosidase characteristics associated with its ability to hydrolyse cellobiose, underscore its utilization in improving the quality of food and beverages. In addition, taking into consideration that the final concentration of ethanol produced by the conventional methods is about 10%, suggests its use in ethanol-containing industrial processes and in the saccharification processes for bioethanol production.
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Affiliation(s)
- Dina H El-Ghonemy
- Microbial Chemistry Department, Genetic Engineering and Biotechnology Research Division, National Research Centre, 33 El Buhouth St, Giza, 12622, Egypt.
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16
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Xu LL, Liu C, Han ZZ, Han H, Yang L, Wang ZT. Microbial Biotransformation of Iridoid Glycosides from Gentiana Rigescens by Penicillium Brasilianum. Chem Biodivers 2020; 17:e2000676. [PMID: 33063468 DOI: 10.1002/cbdv.202000676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 10/15/2020] [Indexed: 01/13/2023]
Abstract
This study aimed to investigate the metabolic effects of endophytic fungi in Gentiana rigescens. From the 100 selected morphospecies, strain 7-2 (Penicillium brasilianum) showed a remarkable biocatalytic activity for gentiopicroside and swertiamarin, yielding seven products, including one new compound, 5-ethylidene-8-hydroxy-4,5,6,8-tetrahydropyrano[3,4-c]pyran-1-one (M04), alongside six known compounds. Gentianine (M01) was the only metabolite of swertiamarin in this study, while the remaining ones were all gentiopicroside metabolites. Among these, five compounds: gentianine (M01), (5S,6S)-5-(hydroxymethyl)-6-methyl-5,6-dihydro-1H,3H-pyrano[3,4-c]pyran-1-one (M02), (5R,6S)-5-(hydroxymethyl)-6-methyl-5,6-dihydro-1H,3H-pyrano[3,4-c]pyran-1-one (M03), 2-(3-formyl-2-oxo-3,6-dihydro-2H-pyran-4-yl)but-3-enoic acid (M06), and 2-oxo-4-(1-oxobut-3-en-2-yl)-3,6-dihydro-2H-pyran-3-carboxylic acid (M07) were similar to gentiopicroside metabolites in humans. Screening the metabolic potential of endophytic fungi in Gentiana rigescens provides an outstanding source for assessing the bioactive metabolites of iridoid glycosides. The above findings suggested that the endophytic fungi of G. rigescens possess multi-enzyme systems that mimic metabolic reactions in mammalian organisms.
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Affiliation(s)
- Li-Li Xu
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China.,Institute of Science, Technology and Humanities, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China
| | - Chang Liu
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China.,Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan, 430071, P. R. China
| | - Zhu-Zhen Han
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China
| | - Han Han
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China.,Experiment Center for Teaching and Learning, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China
| | - Li Yang
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China
| | - Zheng-Tao Wang
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, P. R. China
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Glycosyl hydrolase catalyzed glycosylation in unconventional media. Appl Microbiol Biotechnol 2020; 104:9523-9534. [PMID: 33034701 DOI: 10.1007/s00253-020-10924-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/17/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023]
Abstract
The reversible hydrolytic property of glycosyl hydrolases (GHs) as well as their acceptance of aglycones other than water has provided the abilities of GHs in synthesizing glycosides. Together with desirable physiochemical properties of glycosides and their high commercial values, research interests have been aroused to investigate the synthetic other than the hydrolytic properties of GHs. On the other hand, just like the esterification processes catalyzed by lipases, GH synthetic effectiveness is strongly obstructed by water both thermodynamically and kinetically. Medium engineering by involving organic solvents can be a viable approach to alleviate the obstacles caused by water. However, as native hydrolyases function in water-enriched environments, most GHs display poor catalytic performance in the presence of organic solvents. Some GHs from thermophiles are more tolerant to organic solvents due to their robust folded structures with strong residue interactions. Other than native sources, immobilization, protein engineering, employment of surfactant, and lyophilization have been proved to enhance the GH stability from the native state, which opens up the possibilities for GHs to be employed in unconventional media as synthases. KEY POINTS: • Unconventional media enhance the synthetic ability but destabilize GHs. • Viable approaches are discussed to improve GH stability from the native state. • GHs robust in unconventional media can be valuable industrial synthases.
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Identification of an intracellular β-glucosidase in Aspergillus niger with transglycosylation activity. Appl Microbiol Biotechnol 2020; 104:8367-8380. [DOI: 10.1007/s00253-020-10840-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/29/2020] [Accepted: 08/14/2020] [Indexed: 10/23/2022]
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Sun J, Ma Y, Xu X, Liu Z, Zou L. Molecular cloning and bioinformatics analyses of a GH3 beta-glucosidase from Auricularia heimuer. BIOTECHNOL BIOTEC EQ 2020. [DOI: 10.1080/13102818.2020.1807407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- Jian Sun
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Yisha Ma
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Xinru Xu
- College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Zengcai Liu
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Li Zou
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
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20
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Yin YR, Sang P, Yang FL, Li T, Yang RF, Liu HY, Luo ZL, Li WJ, Yang LQ. Characterization of a Cu 2+, SDS, alcohol and glucose tolerant GH1 β-glucosidase from Bacillus sp. CGMCC 1.16541. Antonie Van Leeuwenhoek 2020; 113:1467-1477. [PMID: 32748077 DOI: 10.1007/s10482-020-01455-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022]
Abstract
A β-glucosidase gene (bsbgl1a) from Bacillus sp. CGMCC 1.16541 was expressed in Escherichia coli BL21 and subsequently characterized. The amino acid sequence shared 83.64% identity with β-glucosidase (WP_066390903.1) from Fictibacillus phosphorivorans. The recombinant β-glucosidase (BsBgl1A) had a molecular weight of 52.2 kDa and could hydrolyze cellobiose, cellotriose, cellotetrose, p-nitrophenyl-β-D-glucopyranoside (pNPG), and p-nitrophenyl-β-D-xylopyranoside (pNPX). Optimal activity for BsBgl1A was recorded at 45 °C with a pH between 5.6 and 7.6, and 100% of its activity was maintained after a 24 h incubation between pH 4 and 9. Kinetic characterization revealed an enzymatic turnover (Kcat) of 616 ± 2 s-1 (with cellobiose) and 3.5 ± 0.1 s-1 (with p-nitrophenyl-β-D-glucopyranoside). Interestingly, the recombinant enzyme showed cupric ion (Cu2+), sodium dodecyl sulfate (SDS) and alcohol tolerance at 10 mM for Cu2+ and 10% for both SDS and alcohol. Additionally, BsBgl1A had high tolerance for glucose (Ki = 2095 mM), which is an extremely desirable feature for industrial applications. Following the addition of BsBgl1A (0.05 mg/ml) to a commercial cellulase reaction system, glucose yields from sugarcane bagasse increased 100% after 1 day at 45 °C. This work identifies a Cu2+, SDS, alcohol, and glucose tolerant GH1 β-glucosidase with potential applications in the hydrolysis of cellulose for the bioenergy industry.
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Affiliation(s)
- Yi-Rui Yin
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Peng Sang
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Feng-Li Yang
- Xiaguan No. 1 Middle School, Dali, 671000, People's Republic of China
| | - Tao Li
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Run-Feng Yang
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Hong-Yan Liu
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Zong-Long Luo
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.
| | - Li-Quan Yang
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China.
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21
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Bermejo PM, Raghavendran V, Gombert AK. Neither 1G nor 2G fuel ethanol: setting the ground for a sugarcane-based biorefinery using an iSUCCELL yeast platform. FEMS Yeast Res 2020; 20:5836716. [PMID: 32401320 DOI: 10.1093/femsyr/foaa027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/11/2020] [Indexed: 11/12/2022] Open
Abstract
First-generation (1G) fuel ethanol production in sugarcane-based biorefineries is an established economic enterprise in Brazil. Second-generation (2G) fuel ethanol from lignocellulosic materials, though extensively investigated, is currently facing severe difficulties to become economically viable. Some of the challenges inherent to these processes could be resolved by efficiently separating and partially hydrolysing the cellulosic fraction of the lignocellulosic materials into the disaccharide cellobiose. Here, we propose an alternative biorefinery, where the sucrose-rich stream from the 1G process is mixed with a cellobiose-rich stream in the fermentation step. The advantages of mixing are 3-fold: (i) decreased concentrations of metabolic inhibitors that are typically produced during pretreatment and hydrolysis of lignocellulosic materials; (ii) decreased cooling times after enzymatic hydrolysis prior to fermentation; and (iii) decreased availability of free glucose for contaminating microorganisms and undesired glucose repression effects. The iSUCCELL platform will be built upon the robust Saccharomyces cerevisiae strains currently present in 1G biorefineries, which offer competitive advantage in non-aseptic environments, and into which intracellular hydrolyses of sucrose and cellobiose will be engineered. It is expected that high yields of ethanol can be achieved in a process with cell recycling, lower contamination levels and decreased antibiotic use, when compared to current 2G technologies.
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Affiliation(s)
| | - Vijayendran Raghavendran
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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Insight into the glycosylation and hydrolysis kinetics of alpha-glucosidase in the synthesis of glycosides. Appl Microbiol Biotechnol 2019; 103:9423-9432. [DOI: 10.1007/s00253-019-10205-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/07/2019] [Accepted: 10/19/2019] [Indexed: 12/13/2022]
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Kim HJ, Lee WH, Turner TL, Kwak S, Jin YS. An extra copy of the β-glucosidase gene improved the cellobiose fermentation capability of an engineered Saccharomyces cerevisiae strain. 3 Biotech 2019; 9:367. [PMID: 31588391 DOI: 10.1007/s13205-019-1899-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/16/2019] [Indexed: 01/06/2023] Open
Abstract
In a previously engineered Saccharomyces cerevisiae recombinant, the cellobiose fermentation rate was significantly lower than the glucose fermentation rate. Thus, we implemented a genome-wide perturbation library to find gene targets for improving the cellobiose fermentation capability of the yeast strain. Unexpectedly, we discovered a transformant that contained an additional β-glucosidase gene (gh1-1), possibly through homologous recombination between the plasmids. The additional β-glucosidase led to the fastest cellobiose fermentation activity among all the transformants evaluated, and the strain demonstrated significantly higher β-glucosidase activity than the control strain, especially during the initial exponential growth phase. The present work revealed the benefit of the extra gh1-1 copy for efficient cellobiose fermentation in the engineered S. cerevisiae strain.
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Affiliation(s)
- Hyo Jin Kim
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 3Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang, 25354 Republic of Korea
- 4Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354 Republic of Korea
| | - Won-Heong Lee
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 5Bioenergy Science and Technology, Chonnam National University, Gwangju, 61186 Korea
| | - Timothy Lee Turner
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 6Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Suryang Kwak
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Yong-Su Jin
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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Kang L, Zhang X, Wang R, Liu C, Yi L, Liu Z, Zhang Z, Yuan S. β-Glucosidase BGL1 from Coprinopsis cinerea Exhibits a Distinctive Hydrolysis and Transglycosylation Activity for Application in the Production of 3-O-β-d-Gentiobiosyl-d-laminarioligosaccharides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:10744-10755. [PMID: 31525900 DOI: 10.1021/acs.jafc.9b04488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We previously reported that β-glucosidase BGL1 at low concentration (15 μg mL-1) from Coprinopsis cinerea exhibited hydrolytic activity only toward laminarioligosaccharides but not toward cellooligosaccharides and gentiobiose. This study shows that BGL1 at high concentration (200 μg mL-1) also hydrolyzed cellobiose and gentiobiose, which accounted for only 0.83 and 2.05% of its activity toward laminaribiose, respectively. Interestingly, BGL1 at low concentration (1.5 μg mL-1) showed transglycosylation but BGL1 at high concentration (200 μg mL-1) did not. BGL1 utilizes only laminarioligosaccharides but not glucose, gentiobiose, and cellobiose to synthesize the higher oligosaccharides. BGL1 transferred one glucosyl residue from substrate laminarioligosaccharide to another laminarioligosaccharide as an acceptor in a β(1 → 3) or β(1 → 6) fashion to produce higher laminarioligosaccharides or 3-O-β-d-gentiobiosyl-d-laminarioligosaccharides. The BGL1-digested laminaritriose exhibited approximately 90% enhancement in the anti-oxidant activity compared to that of untreated laminaritriose, implying a potential application of BGL1-based transglycosylation for the production of high value-added rare oligosaccharides.
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Affiliation(s)
- Liqin Kang
- Jiangsu Key Laboratory for Microbes and Microbial Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science , Nanjing Normal University , Nanjing 210023 , PR China
| | - Xingwei Zhang
- Jiangsu Key Laboratory for Microbes and Microbial Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science , Nanjing Normal University , Nanjing 210023 , PR China
| | - Rui Wang
- Jiangsu Key Laboratory for Microbes and Microbial Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science , Nanjing Normal University , Nanjing 210023 , PR China
| | - Cuicui Liu
- Jiangsu Key Laboratory for Microbes and Microbial Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science , Nanjing Normal University , Nanjing 210023 , PR China
| | - Lin Yi
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences , Soochow University , Suzhou , Jiangsu , 215021 , China
| | - Zhonghua Liu
- Jiangsu Key Laboratory for Microbes and Microbial Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science , Nanjing Normal University , Nanjing 210023 , PR China
| | - Zhenqing Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences , Soochow University , Suzhou , Jiangsu , 215021 , China
| | - Sheng Yuan
- Jiangsu Key Laboratory for Microbes and Microbial Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science , Nanjing Normal University , Nanjing 210023 , PR China
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Srivastava N, Rathour R, Jha S, Pandey K, Srivastava M, Thakur VK, Sengar RS, Gupta VK, Mazumder PB, Khan AF, Mishra PK. Microbial Beta Glucosidase Enzymes: Recent Advances in Biomass Conversation for Biofuels Application. Biomolecules 2019; 9:E220. [PMID: 31174354 PMCID: PMC6627771 DOI: 10.3390/biom9060220] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 01/10/2023] Open
Abstract
The biomass to biofuels production process is green, sustainable, and an advanced technique to resolve the current environmental issues generated from fossil fuels. The production of biofuels from biomass is an enzyme mediated process, wherein β-glucosidase (BGL) enzymes play a key role in biomass hydrolysis by producing monomeric sugars from cellulose-based oligosaccharides. However, the production and availability of these enzymes realize their major role to increase the overall production cost of biomass to biofuels production technology. Therefore, the present review is focused on evaluating the production and efficiency of β-glucosidase enzymes in the bioconversion of cellulosic biomass for biofuel production at an industrial scale, providing its mechanism and classification. The application of BGL enzymes in the biomass conversion process has been discussed along with the recent developments and existing issues. Moreover, the production and development of microbial BGL enzymes have been explained in detail, along with the recent advancements made in the field. Finally, current hurdles and future suggestions have been provided for the future developments. This review is likely to set a benchmark in the area of cost effective BGL enzyme production, specifically in the biorefinery area.
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Affiliation(s)
- Neha Srivastava
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
| | - Rishabh Rathour
- Department of Bioengineering, Integral University, Lucknow 226026, India.
| | - Sonam Jha
- Department of Botany, Banaras Hindu University, Varanasi 221005, India.
| | - Karan Pandey
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
| | - Manish Srivastava
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India.
| | - Vijay Kumar Thakur
- Enhanced Composites and Structures Center, School of Aerospace, Transport and Manufacturing, Cranfield University, Bedfordshire MK43 0AL, UK.
| | - Rakesh Singh Sengar
- Department of Agriculture Biotechnology, College of Agriculture, Sardar Vallabhbhai Patel, University of Agriculture and Technology, Meerut 250110, U.P., India.
| | - Vijai K Gupta
- Department of Chemistry and Biotechnology, ERA Chair of Green Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia.
| | | | - Ahamad Faiz Khan
- Department of Bioengineering, Integral University, Lucknow 226026, India.
| | - Pradeep Kumar Mishra
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
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Méndez-Líter JA, Tundidor I, Nieto-Domínguez M, de Toro BF, González Santana A, de Eugenio LI, Prieto A, Asensio JL, Cañada FJ, Sánchez C, Martínez MJ. Transglycosylation products generated by Talaromyces amestolkiae GH3 β-glucosidases: effect of hydroxytyrosol, vanillin and its glucosides on breast cancer cells. Microb Cell Fact 2019; 18:97. [PMID: 31151435 PMCID: PMC6544938 DOI: 10.1186/s12934-019-1147-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/22/2019] [Indexed: 12/18/2022] Open
Abstract
Background Transglycosylation represents one of the most promising approaches for obtaining novel glycosides, and plant phenols and polyphenols are emerging as one of the best targets for creating new molecules with enhanced capacities. These compounds can be found in diet and exhibit a wide range of bioactivities, such as antioxidant, antihypertensive, antitumor, neuroprotective and anti-inflammatory, and the eco-friendly synthesis of glycosides from these molecules can be a suitable alternative for increasing their health benefits. Results Transglycosylation experiments were carried out using different GH3 β-glucosidases from the fungus Talaromyces amestolkiae. After a first screening with a wide variety of potential transglycosylation acceptors, mono-glucosylated derivatives of hydroxytyrosol, vanillin alcohol, 4-hydroxybenzyl alcohol, and hydroquinone were detected. The reaction products were analyzed by thin-layer chromatography, high-pressure liquid chromatography, and mass spectrometry. Hydroxytyrosol and vanillyl alcohol were selected as the best options for transglycosylation optimization, with a final conversion yield of 13.8 and 19% of hydroxytyrosol and vanillin glucosides, respectively. NMR analysis confirmed the structures of these compounds. The evaluation of the biological effect of these glucosides using models of breast cancer cells, showed an enhancement in the anti-proliferative capacity of the vanillin derivative, and an improved safety profile of both glucosides. Conclusions GH3 β-glucosidases from T. amestolkiae expressed in P. pastoris were able to transglycosylate a wide variety of acceptors. Between them, phenolic molecules like hydroxytyrosol, vanillin alcohol, 4-hydroxybenzyl alcohol, and hydroquinone were the most suitable for its interesting biological properties. The glycosides of hydroxytyrosol and vanillin were tested, and they improved the biological activities of the original aglycons on breast cancer cells. Electronic supplementary material The online version of this article (10.1186/s12934-019-1147-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juan Antonio Méndez-Líter
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Isabel Tundidor
- Department of Biochemistry and Molecular Biology, Complutense University, Madrid, Spain.,Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain
| | - Manuel Nieto-Domínguez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Fernández de Toro
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Andrés González Santana
- Glycochemistry and Molecular Recognition Group, Instituto de Química Orgánica General (IQOG-CSIC), Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Laura Isabel de Eugenio
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Alicia Prieto
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Juan Luis Asensio
- Glycochemistry and Molecular Recognition Group, Instituto de Química Orgánica General (IQOG-CSIC), Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Francisco Javier Cañada
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Cristina Sánchez
- Department of Biochemistry and Molecular Biology, Complutense University, Madrid, Spain.,Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain
| | - María Jesús Martínez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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Geronimo I, Ntarima P, Piens K, Gudmundsson M, Hansson H, Sandgren M, Payne CM. Kinetic and molecular dynamics study of inhibition and transglycosylation in Hypocrea jecorina family 3 β-glucosidases. J Biol Chem 2019; 294:3169-3180. [PMID: 30602567 DOI: 10.1074/jbc.ra118.007027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Indexed: 01/09/2023] Open
Abstract
β-Glucosidases enhance enzymatic biomass conversion by relieving cellobiose inhibition of endoglucanases and cellobiohydrolases. However, the susceptibility of these enzymes to inhibition and transglycosylation at high glucose or cellobiose concentrations severely limits their activity and, consequently, the overall efficiency of enzyme mixtures. We determined the impact of these two processes on the hydrolytic activity of the industrially relevant family 3 β-glucosidases from Hypocrea jecorina, HjCel3A and HjCel3B, and investigated the underlying molecular mechanisms through kinetic studies, binding free energy calculations, and molecular dynamics (MD) simulations. HjCel3B had a 7-fold higher specificity for cellobiose than HjCel3A but greater tendency for glucose inhibition. Energy decomposition analysis indicated that cellobiose has relatively weak electrostatic interactions with binding site residues, allowing it to be easily displaced by glucose and free to inhibit other hydrolytic enzymes. HjCel3A is, thus, preferable as an industrial β-glucosidase despite its lower activity caused by transglycosylation. This competing pathway to hydrolysis arises from binding of glucose or cellobiose at the product site after formation of the glycosyl-enzyme intermediate. MD simulations revealed that binding is facilitated by hydrophobic interactions with Trp-37, Phe-260, and Tyr-443. Targeting these aromatic residues for mutation to reduce substrate affinity at the product site would therefore potentially mitigate transglycosidic activity. Engineering improved variants of HjCel3A and other structurally similar β-glucosidases would have a significant economic effect on enzymatic biomass conversion in terms of yield and production cost as the process can be consequently conducted at higher substrate loadings.
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Affiliation(s)
- Inacrist Geronimo
- From the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| | - Patricia Ntarima
- the Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium, and
| | - Kathleen Piens
- the Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium, and
| | - Mikael Gudmundsson
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Henrik Hansson
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Mats Sandgren
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Christina M Payne
- From the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, .,the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
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Chen Y, Tang S, Chen Y, Zhang R, Zhou M, Wang C, Feng N, Wu Q. Structure-activity relationship of procyanidins on advanced glycation end products formation and corresponding mechanisms. Food Chem 2019; 272:679-687. [DOI: 10.1016/j.foodchem.2018.08.090] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 02/07/2023]
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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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Geronimo I, Payne CM, Sandgren M. Hydrolysis and Transglycosylation Transition States of Glycoside Hydrolase Family 3 β-Glucosidases Differ in Charge and Puckering Conformation. J Phys Chem B 2018; 122:9452-9459. [DOI: 10.1021/acs.jpcb.8b07118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Inacrist Geronimo
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Christina M. Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, United States
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
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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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β-Mannanase-catalyzed synthesis of alkyl mannooligosides. Appl Microbiol Biotechnol 2018; 102:5149-5163. [PMID: 29680901 PMCID: PMC5959982 DOI: 10.1007/s00253-018-8997-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/04/2018] [Accepted: 04/07/2018] [Indexed: 12/28/2022]
Abstract
β-Mannanases catalyze the conversion and modification of β-mannans and may, in addition to hydrolysis, also be capable of transglycosylation which can result in enzymatic synthesis of novel glycoconjugates. Using alcohols as glycosyl acceptors (alcoholysis), β-mannanases can potentially be used to synthesize alkyl glycosides, biodegradable surfactants, from renewable β-mannans. In this paper, we investigate the synthesis of alkyl mannooligosides using glycoside hydrolase family 5 β-mannanases from the fungi Trichoderma reesei (TrMan5A and TrMan5A-R171K) and Aspergillus nidulans (AnMan5C). To evaluate β-mannanase alcoholysis capacity, a novel mass spectrometry-based method was developed that allows for relative comparison of the formation of alcoholysis products using different enzymes or reaction conditions. Differences in alcoholysis capacity and potential secondary hydrolysis of alkyl mannooligosides were observed when comparing alcoholysis catalyzed by the three β-mannanases using methanol or 1-hexanol as acceptor. Among the three β-mannanases studied, TrMan5A was the most efficient in producing hexyl mannooligosides with 1-hexanol as acceptor. Hexyl mannooligosides were synthesized using TrMan5A and purified using high-performance liquid chromatography. The data suggests a high selectivity of TrMan5A for 1-hexanol as acceptor over water. The synthesized hexyl mannooligosides were structurally characterized using nuclear magnetic resonance, with results in agreement with their predicted β-conformation. The surfactant properties of the synthesized hexyl mannooligosides were evaluated using tensiometry, showing that they have similar micelle-forming properties as commercially available hexyl glucosides. The present paper demonstrates the possibility of using β-mannanases for alkyl glycoside synthesis and increases the potential utilization of renewable β-mannans.
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Quantitative multiplexed profiling of Penicillium funiculosum secretome grown on polymeric cellulase inducers and glucose. J Proteomics 2018; 179:150-160. [PMID: 29597011 DOI: 10.1016/j.jprot.2018.03.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/16/2018] [Accepted: 03/20/2018] [Indexed: 11/22/2022]
Abstract
Filamentous fungi respond to the need to secure utilisable carbon from their growth milieu by secreting unique extracellular proteins depending upon the types of polymeric substrates. We have here profiled the variations in the secretome pattern of a non-model hypercellulolytic fungus - Penicillium funiculosum, grown in minimal media containing four different polymeric cellulase inducers, i.e., Avicel, wheat bran, ammonium-pretreated wheat straw and Avicel & wheat bran, and glucose over its early and late log phases of growth. Of the 137 secreted proteins validated at 1% FDR, we identified the quantified proteins in three clusters as early, persistently or lately expressed. The type of carbon substrate present in the culture media significantly affected the levels of cellulolytic enzymes expression by the fungus. The top abundant proteins quantified in the secretome for Avicel and wheat bran were cellobiohydrolaseI [GH7-CBM1], cellobiohydrolaseII [GH6-CBM1], β-glucosidase [GH3], arabinofuranosidase [GH51] and β-xylosidase [GH3], with bicupin being highest in case of wheat straw. Our results further suggested that the fungus secreted the extracellular proteins in waves, such that the initial responders act to hydrolyse the composite substrates in the culture environment before the second wave of proteins which tend to be more tailored to the specific substrate in the cultivating media. BIOLOGICAL SIGNIFICANCE In this article, we have comprehensively examined the dynamics of the secretome of a non-model hypercellulolytic fungus produced in response to model and composite cellulase inducers. Our study has provided additional insights into how the fungus enzyme machinery responds to the presence of different polymeric cellulase inducers over the two different growth phases (early growth and late growth phase). The comprehensive typing and quantification of the different proteins present in the secretomes of the cellulolytic fungal strains in response to diverse nutrient sources hold many prospects in understanding the fungus unique enzyme machinery and dynamics for the downstream biotechnological applications.
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Yun EJ, Oh EJ, Liu JJ, Yu S, Kim DH, Kwak S, Kim KH, Jin YS. Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:140. [PMID: 29785207 PMCID: PMC5950193 DOI: 10.1186/s13068-018-1135-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 04/28/2018] [Indexed: 05/08/2023]
Abstract
BACKGROUND Understanding the global metabolic network, significantly perturbed upon promiscuous activities of foreign enzymes and different carbon sources, is crucial for systematic optimization of metabolic engineering of yeast Saccharomyces cerevisiae. Here, we studied the effects of promiscuous activities of overexpressed enzymes encoded by foreign genes on rerouting of metabolic fluxes of an engineered yeast capable of assimilating sugars from renewable biomass by profiling intracellular and extracellular metabolites. RESULTS Unbiased metabolite profiling of the engineered S. cerevisiae strain EJ4 revealed promiscuous enzymatic activities of xylose reductase and xylitol dehydrogenase on galactose and galactitol, respectively, resulting in accumulation of galactitol and tagatose during galactose fermentation. Moreover, during glucose fermentation, a trisaccharide consisting of glucose accumulated outside of the cells probably owing to the promiscuous and transglycosylation activity of β-glucosidase expressed for hydrolyzing cellobiose. Meanwhile, higher accumulation of fatty acids and secondary metabolites was observed during xylose and cellobiose fermentations, respectively. CONCLUSIONS The heterologous enzymes functionally expressed in S. cerevisiae showed promiscuous activities that led to unintended metabolic rerouting in strain EJ4. Such metabolic rerouting could result in a low yield and productivity of a final product due to the formation of unexpected metabolites. Furthermore, the global metabolic network can be significantly regulated by carbon sources, thus yielding different patterns of metabolite production. This metabolomic study can provide useful information for yeast strain improvement and systematic optimization of yeast metabolism to manufacture bio-based products.
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Affiliation(s)
- Eun Ju Yun
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Eun Joong Oh
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Jing-Jing Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Sora Yu
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Dong Hyun Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Suryang Kwak
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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Geronimo I, Payne CM, Sandgren M. The role of catalytic residue pKa on the hydrolysis/transglycosylation partition in family 3 β-glucosidases. Org Biomol Chem 2018; 16:316-324. [DOI: 10.1039/c7ob02558k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The catalytic acid/base residue (E441) pKa, as modulated by its electrostatic environment, has potential impact on the hydrolysis/transglycosylation partition in β-glucosidases.
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Affiliation(s)
- Inacrist Geronimo
- Department of Molecular Sciences
- Swedish University of Agricultural Sciences
- 750 07 Uppsala
- Sweden
| | - Christina M. Payne
- Department of Chemical and Materials Engineering
- University of Kentucky
- Lexington
- USA
| | - Mats Sandgren
- Department of Molecular Sciences
- Swedish University of Agricultural Sciences
- 750 07 Uppsala
- Sweden
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Kim DH, Kim DH, Lee SH, Kim KH. A novel β-glucosidase from Saccharophagus degradans 2-40 T for the efficient hydrolysis of laminarin from brown macroalgae. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:64. [PMID: 29563967 PMCID: PMC5851131 DOI: 10.1186/s13068-018-1059-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 02/22/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Laminarin is a potential biomass feedstock for the production of glucose, which is the most preferable fermentable sugar in many microorganisms by which it can be converted to biofuels and bio-based chemicals. Also, laminarin is a good resource as functional materials because it consists of β-1,3-glucosidic linkages in its backbone and β-1,6-glucosidic linkages in its branches so that its oligosaccharides driven from laminarin have a variety of biological activities. It is industrially important to be able to produce laminarioligosaccharides as well as glucose from laminarin by a single enzyme because the enzyme cost accounts for a large part of bio-based products. In this study, we investigated the industrial applicability of Bgl1B, a unique β-glucosidase from Saccharophagus degradans 2-40T, belonging to the glycoside hydrolase family 1 (GH1) by characterizing its activity of hydrolyzing laminarin under various conditions. RESULTS Bgl1B was cloned and overexpressed in Escherichia coli from S. degradans 2-40T, and its enzymatic activity was characterized. Similar to most of β-glucosidases in GH1, Bgl1B was able to hydrolyze a variety of disaccharides having different β-linkages, such as laminaribiose, cellobiose, gentiobiose, lactose, and agarobiose, by cleaving β-1,3-, β-1,4-, and β-1,6-glycosidic linkages. However, Bgl1B showed the highest specific activity toward laminaribiose with a β-1,3-glycosidic linkage. In addition, it was able to hydrolyze laminarin, one of the major polysaccharides in brown macroalgae, into glucose with a conversion yield of 75% of theoretical maximum. Bgl1B also showed transglycosylation activity by producing oligosaccharides from laminarin and laminaribiose under a high mass ratio of substrate to enzyme. Furthermore, Bgl1B was found to be psychrophilic, exhibiting relative activity of 59-85% in the low-temperature range of 2-20 °C. CONCLUSIONS Bgl1B can directly hydrolyze laminarin into glucose with a high conversion yield without leaving any oligosaccharides. Bgl1B can exhibit high enzymatic activity in a broad range of low temperatures (2-20 °C), which is advantageous for establishing energy-efficient bioprocesses. In addition, under high substrate to enzyme ratios, Bgl1B can produce high-value laminarioligosaccharides via its transglycosylation activity. These results show that Bgl1B can be an industrially important enzyme for the production of biofuels and bio-based chemicals from brown macroalgae.
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Affiliation(s)
- Dong Hyun Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Do Hyoung Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Sang-Hyun Lee
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
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Singhania RR, Patel AK, Pandey A, Ganansounou E. Genetic modification: A tool for enhancing beta-glucosidase production for biofuel application. BIORESOURCE TECHNOLOGY 2017; 245:1352-1361. [PMID: 28596076 DOI: 10.1016/j.biortech.2017.05.126] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 05/25/2023]
Abstract
Beta-glucosidase (BGL) is a rate-limiting enzyme for cellulose hydrolysis as it acts in the final step of lignocellulosic biomass conversion to convert cellobiose into glucose, the final end product. Most of the fungal strains used for cellulase production are deficient in BGL hence BGL is supplemented into cellulases to have an efficient biomass conversion. Genetic engineering has enabled strain modification to produce BGL optimally with desired properties to be employed for biofuel applications. It has been cloned either directly into the host strains lacking BGL or into another expression system, to be overexpressed so as to be blended into BGL deficient cellulases. In this article, role of genetic engineering to overcome BGL limitations in the cellulase cocktail and its significance for biofuel applications has been critically reviewed.
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Affiliation(s)
- Reeta Rani Singhania
- DBT-IOC Advanced Bio-Energy Research Centre, Indian Oil Corporation; R&D Centre, Sector-13, Faridabad 121007, India
| | - Anil Kumar Patel
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu 96822, HI, United States.
| | - Ashok Pandey
- Center of Innovative and Applied Bioprocessing, Sector 81, Knowledge City PO Manauli, SAS Nagar, Mohali 140306, Punjab, India
| | - Edgard Ganansounou
- Bioenergy and Energy Planning Research Group, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Meleiro LP, Salgado JCS, Maldonado RF, Carli S, Moraes LAB, Ward RJ, Jorge JA, Furriel RPM. Engineering the GH1 β-glucosidase from Humicola insolens: Insights on the stimulation of activity by glucose and xylose. PLoS One 2017; 12:e0188254. [PMID: 29145480 PMCID: PMC5690678 DOI: 10.1371/journal.pone.0188254] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/05/2017] [Indexed: 12/31/2022] Open
Abstract
The activity of the GH1 β-glucosidase from Humicola insolens (Bglhi) against p-nitrophenyl-β-D-glucopyranoside (pNP-Glc) and cellobiose is enhanced 2-fold by glucose and/or xylose. Kinetic and transglycosylation data showed that hydrolysis is preferred in the absence of monosaccharides. Stimulation involves allosteric interactions, increased transglycosylation and competition of the substrate and monosaccharides for the -1 glycone and the +1/+2 aglycone binding sites. Protein directed evolution has been used to generate 6 mutants of Bglhi with altered stimulation patterns. All mutants contain one of three substitutions (N235S, D237V or H307Y) clustered around the +1/+2 aglycone binding sites. Two mutants with the H307Y substitution preferentially followed the transglycosylation route in the absence of xylose or glucose. The strong stimulation of their pNP-glucosidase and cellobiase activities was accompanied by increased transglycosylation and higher monosaccharide tolerance. The D237V mutation favoured hydrolysis over transglycosylation and the pNP-glucosidase activity, but not the cellobiase activity, was stimulated by xylose. The substitution N235S abolished the preference for hydrolysis or transglycosylation; the cellobiase, but not the pNP-glucosidase activity of the mutants was strongly inhibited by xylose. Both the D237V and N235S mutations lowered tolerance to the monosaccharides. These results provide evidence that the fine modulation of the activity of Bglhi and mutants by glucose and/or xylose is regulated by the relative affinities of the glycone and aglycone binding sites for the substrate and the free monosaccharides.
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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, Brasil
- * E-mail:
| | - José Carlos Santos Salgado
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Raquel Fonseca Maldonado
- Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, São José dos Campos, São Paulo, Brasil
| | - Sibeli Carli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Luiz Alberto Beraldo Moraes
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - João Atílio Jorge
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Rosa Prazeres Melo Furriel
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
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Gao J, Qian Y, Wang Y, Qu Y, Zhong Y. Production of the versatile cellulase for cellulose bioconversion and cellulase inducer synthesis by genetic improvement of Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:272. [PMID: 29167702 PMCID: PMC5688634 DOI: 10.1186/s13068-017-0963-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/07/2017] [Indexed: 05/05/2023]
Abstract
BACKGROUND The enzymes for efficient hydrolysis of lignocellulosic biomass are a major factor in the development of an economically feasible cellulose bioconversion process. Up to now, low hydrolysis efficiency and high production cost of cellulases remain the significant hurdles in this process. The aim of the present study was to develop a versatile cellulase system with the enhanced hydrolytic efficiency and the ability to synthesize powerful inducers by genetically engineering Trichoderma reesei. RESULTS In our study, we employed a systematic genetic strategy to construct the carbon catabolite-derepressed strain T. reesei SCB18 to produce the cellulase complex that exhibited a strong cellulolytic capacity for biomass saccharification and an extraordinary high β-glucosidase (BGL) activity for cellulase-inducing disaccharides synthesis. We first identified the hypercellulolytic and uracil auxotrophic strain T. reesei SP4 as carbon catabolite repressed, and then deleted the carbon catabolite repressor gene cre1 in the genome. We found that the deletion of cre1 with the selectable marker pyrG led to a 72.6% increase in total cellulase activity, but a slight reduction in saccharification efficiency. To facilitate the following genetic modification, the marker pyrG was successfully removed by homologous recombination based on resistance to 5-FOA. Furthermore, the Aspergillus niger BGLA-encoding gene bglA was overexpressed, and the generated strain T. reesei SCB18 exhibited a 29.8% increase in total cellulase activity and a 51.3-fold enhancement in BGL activity (up to 103.9 IU/mL). We observed that the cellulase system of SCB18 showed significantly higher saccharification efficiency toward differently pretreated corncob residues than the control strains SDC11 and SP4. Moreover, the crude enzyme preparation from SCB18 with high BGL activity possessed strong transglycosylation ability to synthesize β-disaccharides from glucose. The transglycosylation product was finally utilized as the inducer for cellulase production, which provided a 63.0% increase in total cellulase activity compared to the frequently used soluble inducer, lactose. CONCLUSIONS In summary, we constructed a versatile cellulase system in T. reesei for efficient biomass saccharification and powerful cellulase inducer synthesis by combinational genetic manipulation of three distinct types of genes to achieve the customized cellulase production, thus providing a viable strategy for further strain improvement to reduce the cost of biomass-based biofuel production.
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Affiliation(s)
- Jia Gao
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People’s Republic of China
| | - Yuanchao Qian
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People’s Republic of China
| | - Yifan Wang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People’s Republic of China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People’s Republic of China
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People’s Republic of China
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da Silva AS, Molina JF, Teixeira RSS, Valdivieso Gelves LG, Bon EPS, Ferreira-Leitão VS. Synthesis of disaccharides using β-glucosidases from Aspergillus niger, A. awamori and Prunus dulcis. Biotechnol Lett 2017; 39:1717-1723. [DOI: 10.1007/s10529-017-2409-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 07/26/2017] [Indexed: 12/18/2022]
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Marine microbes as a valuable resource for brand new industrial biocatalysts. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2017. [DOI: 10.1016/j.bcab.2017.06.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Mitsukawa Y, Hibi M, Matsutani N, Horinouchi N, Takahashi S, Ogawa J. Enzymatic synthesis of 2'-O-methylribonucleosides with a nucleoside hydrolase family enzyme from Lactobacillus buchneri LBK78. J Biosci Bioeng 2017; 123:659-664. [PMID: 28202305 DOI: 10.1016/j.jbiosc.2017.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 12/25/2016] [Accepted: 01/10/2017] [Indexed: 10/20/2022]
Abstract
2'-O-Methylribonucleosides (2'-OMe-NRs) are promising raw materials for the production of nucleic acid drugs. We previously reported that LbNH, a nucleoside hydrolase from Lactobacillus buchneri LBK78 (NITE P-01581), was the first enzyme found to act on 2'-OMe-NRs. In the present study, we determined that LbNH also has the transribosylation activity between 2'-OMe-NRs and nucleobases, in addition to the hydrolyzing activity towards 2'-OMe-NRs. When 2'-O-methyluridine (2'-OMe-UR) and adenine were reacted with LbNH, 2'-O-methyladenosine (2'-OMe-AR) was produced. LbNH preferred purine nucleobases as its acceptor substrates for the transribosylation with 2'-OMe-UR as a donor substrate. Kinetic analysis of LbNH revealed that adenine behaved as a mixed inhibitor of the hydrolysis of 2'-OMe-UR. Under the optimal reaction conditions, the maximum molar yield of enzymatic 2'-OMe-AR produced reached 0.97% towards 2'-OMe-UR, corresponding to 0.16 g/L.
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Affiliation(s)
- Yuuki Mitsukawa
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Makoto Hibi
- Industrial Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Narihiro Matsutani
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Nobuyuki Horinouchi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Satomi Takahashi
- Industrial Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Jun Ogawa
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
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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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Kuusk S, Sørlie M, Väljamäe P. Human Chitotriosidase Is an Endo-Processive Enzyme. PLoS One 2017; 12:e0171042. [PMID: 28129403 PMCID: PMC5271402 DOI: 10.1371/journal.pone.0171042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/13/2017] [Indexed: 01/17/2023] Open
Abstract
Human chitotriosidase (HCHT) is involved in immune response to chitin-containing pathogens in humans. The enzyme is able to degrade chitooligosaccharides as well as crystalline chitin. The catalytic domain of HCHT is connected to the carbohydrate binding module (CBM) through a flexible hinge region. In humans, two active isoforms of HCHT are found-the full length enzyme and its truncated version lacking CBM and the hinge region. The active site architecture of HCHT is reminiscent to that of the reducing-end exo-acting processive chitinase ChiA from bacterium Serratia marcescens (SmChiA). However, the presence of flexible hinge region and occurrence of two active isoforms are reminiscent to that of non-processive endo-chitinase from S. marcescens, SmChiC. Although the studies on soluble chitin derivatives suggest the endo-character of HCHT, the mode of action of the enzyme on crystalline chitin is not known. Here, we made a thorough characterization of HCHT in terms of the mode of action, processivity, binding, and rate constants for the catalysis and dissociation using α-chitin as substrate. HCHT efficiently released the end-label from reducing-end labelled chitin and had also high probability (95%) of endo-mode initiation of processive run. These results qualify HCHT as an endo-processive enzyme. Processivity and the rate constant of dissociation of HCHT were found to be in-between those, characteristic to processive exo-enzymes, like SmChiA and randomly acting non-processive endo-enzymes, like SmChiC. Apart from increasing the affinity for chitin, CBM had no major effect on kinetic properties of HCHT.
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Affiliation(s)
- Silja Kuusk
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail:
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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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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Hernández‐Guzmán A, Flores‐Martínez A, Ponce‐Noyola P, Villagómez‐Castro JC. Purification and characterization of an extracellular β-glucosidase from Sporothrix schenckii. FEBS Open Bio 2016; 6:1067-1077. [PMID: 27833847 PMCID: PMC5095144 DOI: 10.1002/2211-5463.12108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/28/2016] [Accepted: 07/25/2016] [Indexed: 01/27/2023] Open
Abstract
An extracellular β-glucosidase (E.C. 3.2.1.21), induced by cellulose in the mycelial form of human pathogen fungus Sporothrix schenckii, was purified to homogeneity using hydroxyapatite (HAp) adsorption chromatography in batch and Sephacryl S200-HR size exclusion chromatography. The molecular mass of the purified enzyme was estimated to be 197 kDa by size exclusion chromatography with a subunit of 96.8 kDa determined by SDS/PAGE. The β-glucosidase exhibited optimum catalytic activity at pH 5.5/45 °C and was relatively stable for up to 24 h at 45 °C. Isoelectric focusing displayed an enzyme with a pI value of 4.0. Its activity was inhibited by Fe2+ but not by any other ions or chelating agents. Km and Vmax values of the purified enzyme were 0.012 mm and 2.56 nmol·min-1·mg-1, respectively, using 4-methylumbelliferyl β-D-glucopyranoside (4-MUG) as the substrate and 44.14 mm and 22.49 nmol·min-1·mg-1 when p-nitrophenyl β-D-glucopyranoside (p-NPG) was used. The purified β-glucosidase was active against cellobioside, laminarin, 4-MUG, and p-NPG and slightly active against 4-methylumbelliferyl β-D-cellobioside and p-nitrophenyl β-D-cellobioside but did not hydrolyze 4-methylumbelliferyl β-D-xyloside, 4-methylumbelliferyl β-D-galactopyranoside nor 4-methylumbelliferyl α-D-glucopyranoside. In addition, the enzyme showed transglycosylation activity when it was incubated along with different oligosaccharides. Whether the transglycosylation and cellulase activities function in vivo as a mechanism involved in the degradation of cellulolytic biomass in the saprophytic stage of S. schenckii remains to be determined.
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Affiliation(s)
- Alicia Hernández‐Guzmán
- Departamento de BiologíaDivisión de Ciencias Naturales y ExactasUniversidad de GuanajuatoMéxico
| | - Alberto Flores‐Martínez
- Departamento de BiologíaDivisión de Ciencias Naturales y ExactasUniversidad de GuanajuatoMéxico
| | - Patricia Ponce‐Noyola
- Departamento de BiologíaDivisión de Ciencias Naturales y ExactasUniversidad de GuanajuatoMéxico
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Gene Amplification on Demand Accelerates Cellobiose Utilization in Engineered Saccharomyces cerevisiae. Appl Environ Microbiol 2016; 82:3631-3639. [PMID: 27084006 DOI: 10.1128/aem.00410-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/06/2016] [Indexed: 01/16/2023] Open
Abstract
UNLABELLED Efficient microbial utilization of cellulosic sugars is essential for the economic production of biofuels and chemicals. Although the yeast Saccharomyces cerevisiae is a robust microbial platform widely used in ethanol plants using sugar cane and corn starch in large-scale operations, glucose repression is one of the significant barriers to the efficient fermentation of cellulosic sugar mixtures. A recent study demonstrated that intracellular utilization of cellobiose by engineered yeast expressing a cellobiose transporter (encoded by cdt-1) and an intracellular β-glucosidase (encoded by gh1-1) can alleviate glucose repression, resulting in the simultaneous cofermentation of cellobiose and nonglucose sugars. Here we report enhanced cellobiose fermentation by engineered yeast expressing cdt-1 and gh1-1 through laboratory evolution. When cdt-1 and gh1-1 were integrated into the genome of yeast, the single copy integrant showed a low cellobiose consumption rate. However, cellobiose fermentation rates by engineered yeast increased gradually during serial subcultures on cellobiose. Finally, an evolved strain exhibited a 15-fold-higher cellobiose fermentation rate. To identify the responsible mutations in the evolved strain, genome sequencing was performed. Interestingly, no mutations affecting cellobiose fermentation were identified, but the evolved strain contained 9 copies of cdt-1 and 23 copies of gh1-1 We also traced the copy numbers of cdt-1 and gh1-1 of mixed populations during the serial subcultures. The copy numbers of cdt-1 and gh1-1 in the cultures increased gradually with similar ratios as cellobiose fermentation rates of the cultures increased. These results suggest that the cellobiose assimilation pathway (transport and hydrolysis) might be a rate-limiting step in engineered yeast and copies of genes coding for metabolic enzymes might be amplified in yeast if there is a growth advantage. This study indicates that on-demand gene amplification might be an efficient strategy for yeast metabolic engineering. IMPORTANCE In order to enable rapid and efficient fermentation of cellulosic hydrolysates by engineered yeast, we delve into the limiting factors of cellobiose fermentation by engineered yeast expressing a cellobiose transporter (encoded by cdt-1) and an intracellular β-glucosidase (encoded by gh1-1). Through laboratory evolution, we isolated mutant strains capable of fermenting cellobiose much faster than a parental strain. Genome sequencing of the fast cellobiose-fermenting mutant reveals that there are massive amplifications of cdt-1 and gh1-1 in the yeast genome. We also found positive and quantitative relationships between the rates of cellobiose consumption and the copy numbers of cdt-1 and gh1-1 in the evolved strains. Our results suggest that the cellobiose assimilation pathway (transport and hydrolysis) might be a rate-limiting step for efficient cellobiose fermentation. We demonstrate the feasibility of optimizing not only heterologous metabolic pathways in yeast through laboratory evolution but also on-demand gene amplification in yeast, which can be broadly applicable for metabolic engineering.
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Agirre J, Ariza A, Offen WA, Turkenburg JP, Roberts SM, McNicholas S, Harris PV, McBrayer B, Dohnalek J, Cowtan KD, Davies GJ, Wilson KS. Three-dimensional structures of two heavily N-glycosylated Aspergillus sp. family GH3 β-D-glucosidases. Acta Crystallogr D Struct Biol 2016; 72:254-65. [PMID: 26894673 PMCID: PMC4756609 DOI: 10.1107/s2059798315024237] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/16/2015] [Indexed: 01/25/2023] Open
Abstract
The industrial conversion of cellulosic plant biomass into useful products such as biofuels is a major societal goal. These technologies harness diverse plant degrading enzymes, classical exo- and endo-acting cellulases and, increasingly, cellulose-active lytic polysaccharide monooxygenases, to deconstruct the recalcitrant β-D-linked polysaccharide. A major drawback with this process is that the exo-acting cellobiohydrolases suffer from severe inhibition from their cellobiose product. β-D-Glucosidases are therefore important for liberating glucose from cellobiose and thereby relieving limiting product inhibition. Here, the three-dimensional structures of two industrially important family GH3 β-D-glucosidases from Aspergillus fumigatus and A. oryzae, solved by molecular replacement and refined at 1.95 Å resolution, are reported. Both enzymes, which share 78% sequence identity, display a three-domain structure with the catalytic domain at the interface, as originally shown for barley β-D-glucan exohydrolase, the first three-dimensional structure solved from glycoside hydrolase family GH3. Both enzymes show extensive N-glycosylation, with only a few external sites being truncated to a single GlcNAc molecule. Those glycans N-linked to the core of the structure are identified purely as high-mannose trees, and establish multiple hydrogen bonds between their sugar components and adjacent protein side chains. The extensive glycans pose special problems for crystallographic refinement, and new techniques and protocols were developed especially for this work. These protocols ensured that all of the D-pyranosides in the glycosylation trees were modelled in the preferred minimum-energy (4)C1 chair conformation and should be of general application to refinements of other crystal structures containing O- or N-glycosylation. The Aspergillus GH3 structures, in light of other recent three-dimensional structures, provide insight into fungal β-D-glucosidases and provide a platform on which to inform and inspire new generations of variant enzymes for industrial application.
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Affiliation(s)
- Jon Agirre
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Antonio Ariza
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Wendy A. Offen
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Johan P. Turkenburg
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Shirley M. Roberts
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Stuart McNicholas
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | | | | | - Jan Dohnalek
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Kevin D. Cowtan
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Gideon J. Davies
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
| | - Keith S. Wilson
- York Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5DD, England
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Larue K, Melgar M, Martin VJJ. Directed evolution of a fungal β-glucosidase in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:52. [PMID: 26949413 PMCID: PMC4778352 DOI: 10.1186/s13068-016-0470-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/22/2016] [Indexed: 05/13/2023]
Abstract
BACKGROUND β-glucosidases (BGLs) catalyze the hydrolysis of soluble cellodextrins to glucose and are a critical component of cellulase systems. In order to engineer Saccharomyces cerevisiae for the production of ethanol from cellulosic biomass, a BGL tailored to industrial bioconversions is needed. RESULTS We applied a directed evolution strategy to a glycosyl hydrolase family 3 (GH3) BGL from Aspergillus niger (BGL1) by expressing a library of mutated bgl1 genes in S. cerevisiae and used a two-step functional screen to identify improved enzymes. Twelve BGL variants that supported growth of S. cerevisiae on cellobiose and showed increased activity on the synthetic substrate p-nitrophenyl-β-D-glucopyranoside were identified and characterized. By performing kinetic experiments, we found that a Tyr → Cys substitution at position 305 of BGL1 dramatically reduced transglycosidation activity that causes inhibition of the hydrolytic reaction at high substrate concentrations. Targeted mutagenesis demonstrated that the position 305 residue is critical in GH3 BGLs and likely determines the extent to which transglycosidation reactions occur. We also found that a substitution at Gln(140) reduced the inhibitory effect of glucose and could be combined with the Y305C substitution to produce a BGL with decreased sensitivity to both the product and substrate. Using the crystal structure of a GH3 BGL from A. aculeatus, we mapped a group of beneficial mutations to the β/α domain of the molecule and postulate that this region modulates activity through subunit interactions. Six BGL variants were identified with substitutions in the MFα pre-sequence that was used to mediate secretion of the protein. Substitutions at Pro(21) or Val(22) of the MFα pre-sequence could produce up to a twofold increase in supernatant hydrolase activity and provides evidence that expression and/or secretion was an additional factor limiting hydrolytic activity. CONCLUSIONS Using directed evolution on BGL1, we identified a key residue that controls hydrolytic and transglycosidation reactions in GH3 BGLs. We also found that several beneficial mutations could be combined and increased the hydrolytic activity for both synthetic and natural substrates.
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Affiliation(s)
- Kane Larue
- Department of Biology, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6 Canada
| | - Mindy Melgar
- Department of Biology, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6 Canada
| | - Vincent J. J. Martin
- Department of Biology, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6 Canada
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