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Yadav SK. Technological advances and applications of hydrolytic enzymes for valorization of lignocellulosic biomass. BIORESOURCE TECHNOLOGY 2017; 245:1727-1739. [PMID: 28552567 DOI: 10.1016/j.biortech.2017.05.066] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 06/07/2023]
Abstract
Hydrolytic enzymes are indispensable tools in the production of various foodstuffs, drugs, and consumables owing to their applications in almost every industrial process nowadays. One of the foremost areas of interest involving the use of hydrolytic enzymes is in the transformation of lignocellulosic biomass into value added products. However, limitations of the processes due to inadequate enzyme activity and stability with a narrow range of pH and temperature optima often limit their effective usage. The innovative technologies, involving manipulation of enzyme activity and stability through mutagenesis, genetic engineering and metagenomics lead to a major leap in all the fields using hydrolytic enzymes. This article provides recent advancement towards the isolation and use of microbes for lignocellulosic biomass utilisation, microbes producing the hydrolytic enzymes, the modern age technologies used to manipulate and enhance the hydrolytic enzyme activity and the applications of such enzymes in value added products development from lignocellulosic biomass.
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Affiliation(s)
- Sudesh Kumar Yadav
- Center of Innovative and Applied Bioprocessing (CIAB), Knowledge City, Sector-81, Mohali, India.
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Baek SC, Ho TH, Lee HW, Jung WK, Gang HS, Kang LW, Kim H. Improvement of enzyme activity of β-1,3-1,4-glucanase from Paenibacillus sp. X4 by error-prone PCR and structural insights of mutated residues. Appl Microbiol Biotechnol 2017; 101:4073-4083. [PMID: 28180917 DOI: 10.1007/s00253-017-8145-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/16/2017] [Accepted: 01/22/2017] [Indexed: 11/29/2022]
Abstract
β-1,3-1,4-Glucanase (BGlc8H) from Paenibacillus sp. X4 was mutated by error-prone PCR or truncated using termination primers to improve its enzyme properties. The crystal structure of BGlc8H was determined at a resolution of 1.8 Å to study the possible roles of mutated residues and truncated regions of the enzyme. In mutation experiments, three clones of EP 2-6, 2-10, and 5-28 were finally selected that exhibited higher specific activities than the wild type when measured using their crude extracts. Enzyme variants of BG2-6, BG2-10, and BG5-28 were mutated at two, two, and six amino acid residues, respectively. These enzymes were purified homogeneously by Hi-Trap Q and CHT-II chromatography. Specific activity of BG5-28 was 2.11-fold higher than that of wild-type BGwt, whereas those of BG2-6 and BG2-10 were 0.93- and 1.19-fold that of the wild type, respectively. The optimum pH values and temperatures of the variants were nearly the same as those of BGwt (pH 5.0 and 40 °C, respectively). However, the half-life of the enzyme activity and catalytic efficiency (k cat/K m) of BG5-28 were 1.92- and 2.12-fold greater than those of BGwt at 40 °C, respectively. The catalytic efficiency of BG5-28 increased to 3.09-fold that of BGwt at 60 °C. These increases in the thermostability and catalytic efficiency of BG5-28 might be useful for the hydrolysis of β-glucans to produce fermentable sugars. Of the six mutated residues of BG5-28, five residues were present in mature BGlc8H protein, and two of them were located in the core scaffold of BGlc8H and the remaining three residues were in the substrate-binding pocket forming loop regions. In truncation experiments, three forms of C-terminal truncated BGlc8H were made, which comprised 360, 286, and 215 amino acid residues instead of the 409 residues of the wild type. No enzyme activity was observed for these truncated enzymes, suggesting the complete scaffold of the α6/α6-double-barrel structure is essential for enzyme activity.
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Affiliation(s)
- Seung Cheol Baek
- Department of Pharmacy, Sunchon National University, Suncheon, 57922, Republic of Korea.,Department of Agricultural Chemistry, Sunchon National University, Suncheon, 57922, Republic of Korea
| | - Thien-Hoang Ho
- Department of Biological Sciences, Konkuk University, Gwangjin-gu, Seoul, 05029, Republic of Korea
| | - Hyun Woo Lee
- Department of Pharmacy, Sunchon National University, Suncheon, 57922, Republic of Korea
| | - Won Kyeong Jung
- Research Institute of Life Pharmaceutical Sciences, Sunchon National University, Suncheon, 57922, Republic of Korea
| | - Hyo-Seung Gang
- Department of Agricultural Chemistry, Sunchon National University, Suncheon, 57922, Republic of Korea
| | - Lin-Woo Kang
- Department of Biological Sciences, Konkuk University, Gwangjin-gu, Seoul, 05029, Republic of Korea.
| | - Hoon Kim
- Department of Pharmacy, Sunchon National University, Suncheon, 57922, Republic of Korea. .,Research Institute of Life Pharmaceutical Sciences, Sunchon National University, Suncheon, 57922, Republic of Korea.
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Maki M, Leung KT, Qin W. The prospects of cellulase-producing bacteria for the bioconversion of lignocellulosic biomass. Int J Biol Sci 2009; 5:500-16. [PMID: 19680472 PMCID: PMC2726447 DOI: 10.7150/ijbs.5.500] [Citation(s) in RCA: 253] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 07/21/2009] [Indexed: 11/05/2022] Open
Abstract
Lignocellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. However, the biorefining process remains economically unfeasible due to a lack of biocatalysts that can overcome costly hurdles such as cooling from high temperature, pumping of oxygen/stirring, and, neutralization from acidic or basic pH. The extreme environmental resistance of bacteria permits screening and isolation of novel cellulases to help overcome these challenges. Rapid, efficient cellulase screening techniques, using cellulase assays and metagenomic libraries, are a must. Rare cellulases with activities on soluble and crystalline cellulose have been isolated from strains of Paenibacillus and Bacillus and shown to have high thermostability and/or activity over a wide pH spectrum. While novel cellulases from strains like Cellulomonas flavigena and Terendinibacter turnerae, produce multifunctional cellulases with broader substrate utilization. These enzymes offer a framework for enhancement of cellulases including: specific activity, thermalstability, or end-product inhibition. In addition, anaerobic bacteria like the clostridia offer potential due to species capable of producing compound multienzyme complexes called cellulosomes. Cellulosomes provide synergy and close proximity of enzymes to substrate, increasing activity towards crystalline cellulose. This has lead to the construction of designer cellulosomes enhanced for specific substrate activity. Furthermore, cellulosome-producing Clostridium thermocellum and its ability to ferment sugars to ethanol; its amenability to co-culture and, recent advances in genetic engineering, offer a promising future in biofuels. The exploitation of bacteria in the search for improved enzymes or strategies provides a means to upgrade feasibility for lignocellulosic biomass conversion, ultimately providing means to a 'greener' technology.
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Affiliation(s)
- Miranda Maki
- Biorefining Research Initiative, Lakehead University, Thunder Bay, Ontario, Canada
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Cho KM, Math RK, Hong SY, Asraful Islam SM, Kim JO, Hong SJ, Kim H, Yun HD. Changes in the activity of the multifunctional β-glycosyl hydrolase (Cel44C-Man26A) from Paenibacillus polymyxa by removal of the C-terminal region to minimum size. Biotechnol Lett 2008; 30:1061-8. [DOI: 10.1007/s10529-008-9640-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 01/07/2008] [Accepted: 01/07/2008] [Indexed: 11/27/2022]
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Cho KM, Hong SY, Lee SM, Kim YH, Kahng GG, Kim H, Yun HD. A cel44C-man26A gene of endophytic Paenibacillus polymyxa GS01 has multi-glycosyl hydrolases in two catalytic domains. Appl Microbiol Biotechnol 2006; 73:618-30. [PMID: 16912849 DOI: 10.1007/s00253-006-0523-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 05/27/2006] [Accepted: 05/29/2006] [Indexed: 11/28/2022]
Abstract
A bacterial strain Paenibacillus polymyxa GS01 was isolated from the interior of the roots of Korean cultivars of ginseng (Panax ginseng C. A. Meyer). The cel44C-man26A gene was cloned from this endophytic strain. This 4,056-bp gene encodes for a 1,352-aa protein which, based on BLAST search homologies, contains a glycosyl hydrolase family 44 (GH44) catalytic domain, a fibronectin domain type 3, a glycosyl hydrolase family 26 (GH26) catalytic domain, and a cellulose-binding module type 3. The multifunctional enzyme domain GH44 possesses cellulase, xylanase, and lichenase activities, while the enzyme domain GH26 possesses mannanase activity. The Cel44C enzyme expressed in and purified from Escherichia coli has an optimum pH of 7.0 for cellulase and lichenase activities, but is at an optimum pH of 5.0 for xylanase and mannanase activities. The optimum temperature for enzymatic activity was 50 degrees C for all substrates. No detectable enzymatic activity was detected for the Cel44C-Man26A mutants E91A and E222A. These results suggest that the amino acid residues Glu(91) and Glu(222) may play an important role in the glycosyl hydrolases activity of Cel44C-Man26A.
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Affiliation(s)
- Kye Man Cho
- Division of Applied Life Science, Gyeongsang National University, Chinju 660-701, South Korea
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