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Maati J, Prazeres DM, Grąz M, Wiater A, Jarosz-Wilkołazka A, Smaali I. Heteroxylan hydrolysis by a recombinant cellulase-free GH10 xylanase from the alkaliphilic bacterium Halalkalibacterium halodurans C-125. Arch Microbiol 2024; 206:261. [PMID: 38753095 DOI: 10.1007/s00203-024-03982-w] [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: 03/03/2024] [Revised: 04/13/2024] [Accepted: 04/25/2024] [Indexed: 06/18/2024]
Abstract
The search for affordable enzymes with exceptional characteristics is fundamental to overcoming industrial and environmental constraints. In this study, a recombinant GH10 xylanase (Xyn10-HB) from the extremely alkaliphilic bacterium Halalkalibacterium halodurans C-125 cultivated at pH 10 was cloned and expressed in E. coli BL21(DE3). Removal of the signal peptide improved the expression, and an overall activity of 8 U/mL was obtained in the cell-free supernatant. The molecular weight of purified Xyn10-HB was estimated to be 42.6 kDa by SDS-PAGE. The enzyme was active across a wide pH range (5-10) with optimal activity recorded at pH 8.5 and 60 °C. It also presented good stability with a half-life of 3 h under these conditions. Substrate specificity studies showed that Xyn10-HB is a cellulase-free enzyme that conventionally hydrolyse birchwood and oat spelts xylans (Apparent Km of 0.46 mg/mL and 0.54 mg/mL, respectively). HPLC analysis showed that both xylans hydrolysis produced xylooligosaccharides (XOS) with a degree of polymerization (DP) ranging from 2 to 9. The conversion yield was 77% after 24 h with xylobiose and xylotriose as the main end-reaction products. When assayed on alkali-extracted wheat straw heteroxylan, the Xyn10-HB produced active XOS with antioxidant activity determined by the DPPH radical scavenging method (IC50 of 0.54 mg/mL after 4 h). Owing to its various characteristics, Xyn10-HB xylanase is a promising candidate for multiple biotechnological applications.
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Affiliation(s)
- Jihene Maati
- University of Carthage, Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB-LR11ES24), INSAT-BP 676, 1080, Tunis Cedex, Tunisia
| | - Duarte Miguel Prazeres
- Institute for Bioengineering and Biosciences-iBB, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
- Institute for Health and Bioeconomy-li4HB, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
| | - Marcin Grąz
- Department of Biochemistry and Biotechnology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Adrian Wiater
- Department of Industrial and Environmental Microbiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Anna Jarosz-Wilkołazka
- Department of Biochemistry and Biotechnology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Issam Smaali
- University of Carthage, Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB-LR11ES24), INSAT-BP 676, 1080, Tunis Cedex, Tunisia.
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Xu Y, Dong F, Wang R, Ajmal M, Liu X, Lin H, Chen H. Alternative splicing analysis of lignocellulose-degrading enzyme genes and enzyme variants in Aspergillus niger. Appl Microbiol Biotechnol 2024; 108:302. [PMID: 38639796 PMCID: PMC11031446 DOI: 10.1007/s00253-024-13137-y] [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: 01/09/2024] [Revised: 03/22/2024] [Accepted: 04/03/2024] [Indexed: 04/20/2024]
Abstract
Alternative splicing (AS) greatly expands the protein diversity in eukaryotes. Although AS variants have been frequently reported existing in filamentous fungi, it remains unclear whether lignocellulose-degrading enzyme genes in industrially important fungi undergo AS events. In this work, AS events of lignocellulose-degrading enzymes genes in Aspergillus niger under two carbon sources (glucose and wheat straw) were investigated by RNA-Seq. The results showed that a total of 23 out of the 56 lignocellulose-degrading enzyme genes had AS events and intron retention was the main type of these AS events. The AS variant enzymes from the annotated endo-β-1,4-xylanase F1 gene (xynF1) and the endo-β-1,4-glucanase D gene (eglD), noted as XYNF1-AS and EGLD-AS, were characterized compared to their normal splicing products XYNF1 and EGLD, respectively. The AS variant XYNF1-AS displayed xylanase activity whereas XYNF1 did not. As for EGLD-AS and EGLD, neither of them showed annotated endo-β-1,4-glucanase activity. Instead, both showed lytic polysaccharide monooxygenase (LPMO) activity with some differences in catalytic properties. Our work demonstrated that the AS variants in A. niger were good sources for discovering novel lignocellulose-degrading enzymes. KEY POINTS: • AS events were identified in the lignocellulose-degrading enzyme genes of A. niger. • New β-1,4-xylanase and LPMO derived from AS events were characterized.
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Affiliation(s)
- Yifan Xu
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China
| | - Feiyu Dong
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China
| | - Ruoxin Wang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China
| | - Maria Ajmal
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China
| | - Xinyu Liu
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China
| | - Hui Lin
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Hongge Chen
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China.
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Xia Y, Wang W, Wei Y, Guo C, Song S, Cai S, Miao Y. Clustered surface amino acid residues modulate the acid stability of GH10 xylanase in fungi. Appl Microbiol Biotechnol 2024; 108:216. [PMID: 38363378 PMCID: PMC10873454 DOI: 10.1007/s00253-024-13045-1] [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: 12/23/2023] [Revised: 01/15/2024] [Accepted: 01/28/2024] [Indexed: 02/17/2024]
Abstract
Acidic xylanases are widely used in industries such as biofuels, animal feeding, and fruit juice clarification due to their tolerance to acidic environments. However, the factors controlling their acid stability, especially in GH10 xylanases, are only partially understood. In this study, we identified a series of thermostable GH10 xylanases with optimal temperatures ranging from 70 to 90 °C, and among these, five enzymes (Xyn10C, Xyn10RE, Xyn10TC, Xyn10BS, and Xyn10PC) exhibited remarkable stability at pH 2.0. Our statistical analysis highlighted several factors contributing to the acid stability of GH10 xylanases, including electrostatic repulsion, π-π stacking, ionic bonds, hydrogen bonds, and Van der Waals interactions. Furthermore, through mutagenesis studies, we uncovered that acid stability is influenced by a complex interplay of amino acid residues. The key amino acid sites determining the acid stability of GH10 xylanases were thus elucidated, mainly concentrated in two surface regions behind the enzyme active center. Notably, the critical residues associated with acid stability markedly enhanced Xyn10RE's thermostability by more than sixfold, indicating a potential acid-thermal interplay in GH10 xylanases. This study not only reported a series of valuable genes but also provided a range of modification targets for enhancing the acid stability of GH10 xylanases. KEY POINTS: • Five acid stable and thermostable GH10 xylanases were reported. • The key amino acid sites, mainly forming two enriched surface regions behind the enzyme active center, were identified responsible for acid stability of GH10 xylanases. • The finding revealed interactive amino acid sites, offering a pathway for synergistic enhancement of both acid stability and thermostability in GH10 xylanase modifications.
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Affiliation(s)
- Yanwei Xia
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wei Wang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yaning Wei
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chuanxu Guo
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Sisi Song
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Siqi Cai
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Youzhi Miao
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, China.
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Paul M, Banerjee A, Maiti S, Mitra D, DasMohapatra PK, Thatoi H. Evaluation of substrate specificity and catalytic promiscuity of Bacillus albus cellulase: an insight into in silico proteomic study aiming at enhanced production of renewable energy. J Biomol Struct Dyn 2023:1-23. [PMID: 38126200 DOI: 10.1080/07391102.2023.2295971] [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: 05/09/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Cellulases are enzymes that aid in the hydrolysis of cellulosic fibers and have a wide range of industrial uses. In the present in silico study, sequence alignment between cellulases from different Bacillus species revealed that most of the residues are conserved in those aligned enzymes. Three dimensional structures of cellulase enzymes from 23 different Bacillus species have been predicted and based on the alignment between the modeled structures, those enzymes have been categorized into 7 different groups according to the homology in their conformational folds. There are two structural contents in Gr-I cellulase namely β1-α2 and β3-α5 loops which varies greatly according to their static position. Molecular docking study between the B. albus cellulase and its various cellulosic substrates including xylanoglucan oligosaccharides revealed that residues viz. Phe154, Tyr258, Tyr282, Tyr285, and Tyr376 of B. albus cellulase are significantly involved in formation stacking interaction during enzyme-substrate binding. Residue interaction network and binding energy analysis for the B. albus cellulase with different cellulosic substrates depicted the strong affinity of XylGlc3 substrate with the receptor enzyme. Molecular interaction and molecular dynamics simulation studies exhibited structural stability of enzyme-substrate complexes which are greatly influenced by the presence of catalytic promiscuity in their substrate binding sites. Screening of B. albus in carboxymethylcellulose (CMC) and xylan supplemented agar media revealed the capability of the bacterium in degrading both cellulose and xylan. Overall, the study demonstrated B. albus cellulase as an effective biocatalyst candidate with the potential role of catalytic promiscuity for possible applications in biofuel industries.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Manish Paul
- Department of Biotechnology, Maharaja Sriram Chandra Bhanja Deo University, Baripada, India
- Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
| | - Amrita Banerjee
- Oriental Institute of Science and Technology, Midnapore, India
| | - Smarajit Maiti
- Oriental Institute of Science and Technology, Midnapore, India
| | - Debanjan Mitra
- Department of Microbiology, Raiganj University, Raiganj, India
| | - Pradeep K DasMohapatra
- Department of Microbiology, Raiganj University, Raiganj, India
- PAKB Environment Conservation Centre, Raiganj University, Raiganj, India
| | - Hrudayanath Thatoi
- Department of Biotechnology, Maharaja Sriram Chandra Bhanja Deo University, Baripada, India
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Zhang J, Qin Y, Wang Q, Liu S, Zhou J, He B, Liang X, Xian L, Wu J. Gene cloning, expression, and characterization of two endo-xylanases from Bacillus velezensis and Streptomyces rochei, and their application in xylooligosaccharide production. Front Microbiol 2023; 14:1292726. [PMID: 38173671 PMCID: PMC10762781 DOI: 10.3389/fmicb.2023.1292726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/21/2023] [Indexed: 01/05/2024] Open
Abstract
Endo-xylanase hydrolyzing xylan in cellulosic residues releasing xylobiose as the major product at neutral pH are desirable in the substitute sweeteners industry. In this study, two endo-xylanases were obtained from Streptomyces rochei and Bacillus velezensis. SrocXyn10 showed the highest identity of 77.22%, with a reported endo-xylanase. The optimum reaction temperature and pH of rSrocXyn10-Ec were pH 7.0 and 60°C, with remarkable stability at 45°C or pHs ranging from 4.5 to 11.0. rBvelXyn11-Ec was most active at pH 6.0 and 50°C, and was stable at 35°C or pH 3.5 to 10.5. Both rSrocXyn10-Ec and rBvelXyn11-Ec showed specific enzyme activities on wheat arabinoxylan (685.83 ± 13.82 and 2809.89 ± 21.26 U/mg, respectively), with no enzyme activity on non-xylan substrates. The Vmax of rSrocXyn10-Ec and rBvelXyn11-Ec were 467.86 U mg-1 and 3067.68 U mg-1, respectively. The determined Km values of rSrocXyn10-Ec and rBvelXyn11-Ec were 3.08 g L-1 and 1.45 g L-1, respectively. The predominant product of the hydrolysis of alkaline extracts from bagasse, corncob, and bamboo by rSrocXyn10-Ec and rBvelXyn11-Ec were xylooligosaccharides. Interestingly, the xylobiose content in hydrolysates by rSrocXyn10-Ec was approximately 80%, which is higher than most reported endo-xylanases. rSrocXyn10-Ec and rBvelXyn11-Ec could be excellent candidates to produce xylooligosaccharides at neutral/near-neutral pHs. rSrocXyn10-Ec also has potential value in the production of xylobiose as a substitute sweetener.
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Affiliation(s)
- Jing Zhang
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Yan Qin
- National Key Laboratory of Non-food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning, China
| | - Qingyan Wang
- National Key Laboratory of Non-food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning, China
| | - Sijia Liu
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Jin Zhou
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Baoxiang He
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Xinquan Liang
- College of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Liang Xian
- National Key Laboratory of Non-food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning, China
| | - Junhua Wu
- National Key Laboratory of Non-food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning, China
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Liu M, Huang S, Yan P, Yin H, Yu J, Wu X, Wang L. Effective Degradation of Brewer Spent Grains by a Novel Thermostable GH10 Xylanase. Appl Biochem Biotechnol 2023:10.1007/s12010-023-04779-1. [PMID: 37979082 DOI: 10.1007/s12010-023-04779-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Brewer spent grains (BSGs) are one of the most abundant by-products in brewing industry. Due to microbiological instability and high perishability, the efficient degradation of BSGs is of environmental and economic importance. Streptomyces sp. F-3 could grow in the medium with BSGs as the only carbon and nitrogen source. Proteome mass spectrometry revealed that a GH10 xylanase SsXyn10A could be secreted in large quantities. SsXyn10A showed optimum activity at pH 7.0 and 60 °C. SsXyn10A exhibited excellent thermostability which retained approximately 100% and 58% after incubation for 5 h at 50 and 60 °C. SsXyn10A displayed high activity to beechwood xylan (BX) and wheat arabinoxylan (WAX). SsXyn10A is active against xylotetracose (X4), xylopentose (X5), and xylohexose (X6) to produce main products xylobiose (X2) and xylotriose (X3). Ssxyn10A showed synergistic effects with commercial cellulase on BSGs hydrolyzing into soluble sugar. In addition, the steam explosion pretreatment of BSGs as the substrate produced twice as much reducing sugar as the degradation of the original substrate. This study will contribute to efficient utilization of BSGs and provide a thermostable GH10 xylanase which has potential application in biomass hydrolysis.
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Affiliation(s)
- Mengyu Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, 72 Binhai Road, Jimo District, Qingdao, Shandong, 266237, China
| | - Shuxia Huang
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, 56 Dengzhou Road, Shibei District, Qingdao, Shandong, 266000, China
| | - Peng Yan
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, 56 Dengzhou Road, Shibei District, Qingdao, Shandong, 266000, China
| | - Hua Yin
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, 56 Dengzhou Road, Shibei District, Qingdao, Shandong, 266000, China
| | - Junhong Yu
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, 56 Dengzhou Road, Shibei District, Qingdao, Shandong, 266000, China.
| | - Xiuyun Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, 72 Binhai Road, Jimo District, Qingdao, Shandong, 266237, China.
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, 72 Binhai Road, Jimo District, Qingdao, Shandong, 266237, China
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Liu YD, Yuan G, An YT, Zhu ZR, Li G. Molecular cloning and characterization of a novel bifunctional cellobiohydrolase/β-xylosidase from a metagenomic library of mangrove soil. Enzyme Microb Technol 2023; 162:110141. [DOI: 10.1016/j.enzmictec.2022.110141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 09/19/2022] [Accepted: 10/09/2022] [Indexed: 11/05/2022]
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Metasecretome and biochemical analysis of consortium PM-06 during the degradation of nixtamalized maize pericarp. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2023. [DOI: 10.1016/j.bcab.2023.102634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Application of Endoxylanases of Bacillus halodurans for Producing Xylooligosaccharides from Empty Fruit Bunch. Catalysts 2022. [DOI: 10.3390/catal13010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Endo-1,4-β-xylanase catalyzes the random hydrolysis of β-1,4-D-xylosidic bonds in xylan, resulting in the formation of oligomers of xylose. This study aims to demonstrate the promise of endoxylanases from alkaliphilic Bacillus halodurans for the production of xylooligosaccharides (XOS) from oil palm empty fruit bunch (EFB) at high pH. Two enzyme preparations were employed: recombinant endoxylanase Xyn45 (GH10 xylanase) and nonrecombinant endoxylanases, a mixture of two extracellular endo-1,4-β-xylanases Xyn45 and Xyn23 (GH11 xylanase) produced by B. halodurans. EFB was first treated with an alkaline solution. Then, the dissolved xylan-containing fraction was retained, and a prepared enzyme was added to react at pH 8 to convert xylan into XOS. Compared with the use of only Xyn45, the combined use of Xyn45 and Xyn23 resulted in a higher yield of XOS, suggesting the synergistic effect of the two endoxylanases. The yield of XOS obtained from EFB was as high as 46.77% ± 1.64% (w/w), with the xylobiose-to-xylotriose ratio being 6:5. However, when the enzyme activity dose was low, the product contained more xylotriose than xylobiose. Four probiotic lactobacilli and bifidobacteria grew well on a medium containing XOS from EFB. The presence of XOS increased cell mass and reduced pH, suggesting that XOS promoted the growth of probiotics.
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Activity-based protein profiling reveals dynamic substrate-specific cellulase secretion by saprotrophic basidiomycetes. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:6. [PMID: 35418096 PMCID: PMC8764865 DOI: 10.1186/s13068-022-02107-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/06/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Fungal saccharification of lignocellulosic biomass occurs concurrently with the secretion of a diverse collection of proteins, together functioning as a catalytic system to liberate soluble sugars from insoluble composite biomaterials. How different fungi respond to different substrates is of fundamental interest to the developing biomass saccharification industry. Among the cornerstones of fungal enzyme systems are the highly expressed cellulases (endo-β-glucanases and cellobiohydrolases). Recently, a cyclophellitol-derived activity-based probe (ABP-Cel) was shown to be a highly sensitive tool for the detection and identification of cellulases.
Results
Here we show that ABP-Cel enables endo-β-glucanase profiling in diverse fungal secretomes. In combination with established ABPs for β-xylanases and β-d-glucosidases, we collected multiplexed in-gel fluorescence activity-based protein profiles of 240 secretomes collected over ten days from biological replicates of ten different basidiomycete fungi grown on maltose, wheat straw, or aspen pulp. Our results reveal the remarkable dynamics and unique enzyme fingerprints associated with each species substrate combination. Chemical proteomic analysis identifies significant arsenals of cellulases secreted by each fungal species during growth on lignocellulosic biomass. Recombinant production and characterization of a collection of probe-reactive enzymes from GH5, GH10, and GH12 confirm that ABP-Cel shows broad selectivity towards enzymes with endo-β-glucanase activity.
Conclusion
Using small-volume samples with minimal sample preparation, the results presented here demonstrate the ready accessibility of sensitive direct evidence for fungal enzyme secretion during early stages of growth on complex lignocellulosic substrates.
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Li Y, Song W, Han X, Wang Y, Rao S, Zhang Q, Zhou J, Li J, Liu S, Du G. Recent progress in key lignocellulosic enzymes: Enzyme discovery, molecular modifications, production, and enzymatic biomass saccharification. BIORESOURCE TECHNOLOGY 2022; 363:127986. [PMID: 36126851 DOI: 10.1016/j.biortech.2022.127986] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 05/15/2023]
Abstract
Lignocellulose, the most prevalent biomass on earth, can be enzymatically converted into carbohydrates for bioethanol production and other uses. Among lignocellulosic enzymes, endoglucanase, xylanase, and laccase are the key enzymes, owing to their ability to disrupt the main structure of lignocellulose. Recently, new discovery methods have been established to obtain key lignocellulosic enzymes with excellent enzymatic properties. Molecular modification of enzymes to modulate their thermostability, catalytic activity, and substrate specificity has been performed with protein engineering technology. In addition, the enzyme expression has been effectively improved through expression element screening and host modification, as well as fermentation optimization. Immobilization of enzymes, use of surfactants, synergistic degradation, and optimization of reaction conditions have addressed the inefficiency of enzymatic saccharification. In this review, recent advances in key lignocellulosic enzymes are summarized, along with future prospects for the development of super-engineered strains and integrative technologies for enzymatic biomass saccharification.
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Affiliation(s)
- Yangyang Li
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Weiyan Song
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Xuyue Han
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Yachan Wang
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Shengqi Rao
- College of Food Science and Engineering, Yangzhou University, Yangzhou 214122, China
| | - Quan Zhang
- Dalian Research Institute of Petroleum and Petrochemicals, SINOPEC, Dalian 116000, China
| | - Jingwen Zhou
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jianghua Li
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Song Liu
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
| | - Guocheng Du
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
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Zhang Y, Liu Y, Zeng C, Shu Y, Wang X, Liang S, Wang S, Zhan R, Wang K. Characterization of two novel highly active glycoside hydrolase family 53 endo-1,4-β-galactanases and their synergism with other carbohydrases in plant polysaccharide decomposition. Int J Biol Macromol 2022; 224:653-666. [DOI: 10.1016/j.ijbiomac.2022.10.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/16/2022] [Accepted: 10/18/2022] [Indexed: 11/05/2022]
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13
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Wang F, Yao Z, Zhang X, Han Z, Chu X, Ge X, Lu F, Liu Y. High-level production of xylose from agricultural wastes using GH11 endo-xylanase and GH43 β-xylosidase from Bacillus sp. Bioprocess Biosyst Eng 2022; 45:1705-1717. [PMID: 36063213 DOI: 10.1007/s00449-022-02778-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/23/2022] [Indexed: 11/24/2022]
Abstract
As a promising feedstock, alkali-extracted xylan from lignocellulosic biomass is desired for producing xylose, which can be used for renewable biofuels production. In this study, an efficient pathway has been established for low-cost and high-yield production of xylose by hydrolysis of alkali-extracted xylan from agricultural wastes using an endo-1,4-xylanase (XYLA) from Bacillus safensis TCCC 111022 and a β-xylosidase (XYLO) from B. pumilus TCCC 11573. The optimum activities of recombinant XYLA (rXYLA) and XYLO (rXYLO) were 60 ℃ and pH 8.0, and 30 ℃ and pH 7.0, respectively. They were stable over a broad pH range (pH 6.0-11.0 and 7.0-10.0). rXYLO showed a relatively high xylose tolerance up to 100 mM. Furthermore, the yield of xylose from wheat straw, rice straw, corn stover, corncob and sugarcane bagasse by rXYLA and rXYLO was 63.77%, 71.76%, 68.55%, 53.81%, and 58.58%, respectively. This study demonstrated a strategy to produce xylose from agricultural wastes by integrating alkali-extracted xylan and enzymatic hydrolysis.
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Affiliation(s)
- Fenghua Wang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China
| | - Zhiming Yao
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China
| | - Xue Zhang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China
| | - Zhuoxuan Han
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China
| | - Xiuxiu Chu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China
| | - Xiuqi Ge
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China
| | - Fuping Lu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China.
| | - Yihan Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economic and Technological Development Area, Tianjin, 300457, People's Republic of China.
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Wu X, Shi Z, Tian W, Liu M, Huang S, Liu X, Yin H, Wang L. A thermostable and CBM2-linked GH10 xylanase from Thermobifida fusca for paper bleaching. Front Bioeng Biotechnol 2022; 10:939550. [PMID: 36091429 PMCID: PMC9459120 DOI: 10.3389/fbioe.2022.939550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/02/2022] [Indexed: 11/25/2022] Open
Abstract
Xylanases have the potential to be used as bio-deinking and bio-bleaching materials and their application will decrease the consumption of the chlorine-based chemicals currently used for this purpose. However, xylanases with specific properties could act effectively, such as having significant thermostability and alkali resistance, etc. In this study, we found that TfXyl10A, a xylanase from Thermobifida fusca, was greatly induced to transcript by microcrystalline cellulose (MCC) substrate. Biochemical characterization showed that TfXyl10A is optimally effective at temperature of 80 °C and pH of 9.0. After removing the carbohydrate-binding module (CBM) and linker regions, the optimum temperature of TfXyl10A-CD was reduced by 10°C (to 70°C), at which the enzyme’s temperature tolerance was also weakened. While truncating only the CBM domain (TfXyl10AdC) had no significant effect on its thermostability. Importantly, polysaccharide-binding experiment showed that the auxiliary domain CBM2 could specifically bind to cellulose substrates, which endowed xylanase TfXyl10A with the ability to degrade xylan surrounding cellulose. These results indicated that TfXyl10A might be an excellent candidate in bio-bleaching processes of paper industry. In addition, the features of active-site architecture of TfXyl10A in GH10 family were further analyzed. By mutating each residue at the -2 and -1 subsites to alanine, the binding force and enzyme activity of mutants were observably decreased. Interestingly, the mutant E51A, locating at the distal -3 subsite, exhibited 90% increase in relative activity compared with wild-type (WT) enzyme TfXyl10A-CD (the catalytic domain of TfXyl110A). This study explored the function of a GH10 xylanase containing a CBM2 domain and the contribution of amino acids in active-site architecture to catalytic activity. The results obtained provide guidance for the rational design of xylanases for industrial applications under high heat and alkali-based operating conditions, such as paper bleaching.
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Affiliation(s)
- Xiuyun Wu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
- State Key Laboratory of Biological Fermentation Engineering of Beer, Qingdao, China
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Zelu Shi
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Wenya Tian
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Mengyu Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Shuxia Huang
- State Key Laboratory of Biological Fermentation Engineering of Beer, Qingdao, China
| | - Xinli Liu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Hua Yin
- State Key Laboratory of Biological Fermentation Engineering of Beer, Qingdao, China
- *Correspondence: Hua Yin, ; Lushan Wang,
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
- *Correspondence: Hua Yin, ; Lushan Wang,
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15
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Glekas PD, Kalantzi S, Dalios A, Hatzinikolaou DG, Mamma D. Biochemical and Thermodynamic Studies on a Novel Thermotolerant GH10 Xylanase from Bacillus safensis. Biomolecules 2022; 12:biom12060790. [PMID: 35740915 PMCID: PMC9221164 DOI: 10.3390/biom12060790] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/01/2022] [Accepted: 06/04/2022] [Indexed: 02/05/2023] Open
Abstract
Xylanases have a broad range of applications in agro-industrial processes. In this study, we report on the discovery and characterization of a new thermotolerant GH10 xylanase from Bacillus safensis, designated as BsXyn10. The xylanase gene (bsxyn10) was cloned from Bacillus safensis and expressed in Escherichia coli. The reduced molecular mass of BsXyn10 was 48 kDa upon SDS-PAGE. Bsxyn10 was optimally active at pH 7.0 and 60 °C, stable over a broad range of pH (5.0–8.0), and also revealed tolerance toward different modulators (metal cations, EDTA). The enzyme was active toward various xylans with no activity on the glucose-based polysaccharides. KM, vmax, and kcat for oat spelt xylan hydrolysis were found to be 1.96 g·L−1, 58.6 μmole·min−1·(mg protein)−1, and 49 s−1, respectively. Thermodynamic parameters for oat spelt xylan hydrolysis at 60 °C were ΔS* = −61.9 J·mol−1·K−1, ΔH* = 37.0 kJ·mol−1 and ΔG* = 57.6 kJ·mol−1. BsXyn10 retained high levels of activity at temperatures up to 60 °C. The thermodynamic parameters (ΔH*D, ΔG*D, ΔS*D) for the thermal deactivation of BsXyn10 at a temperature range of 40–80 °C were: 192.5 ≤ ΔH*D ≤ 192.8 kJ·mol−1, 262.1 ≤ ΔS*D ≤ 265.8 J·mol−1·K−1, and 99.9 ≤ ΔG*D ≤ 109.6 kJ·mol−1. The BsXyn10-treated oat spelt xylan manifested the catalytic release of xylooligosaccharides of 2–6 DP, suggesting that BsXyn10 represents a promising candidate biocatalyst appropriate for several biotechnological applications.
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Affiliation(s)
- Panayiotis D. Glekas
- Enzyme and Microbial Biotechnology Unit, Department of Biology, Zografou Campus, National and Kapodistrian University of Athens, 15784 Athens, Greece;
| | - Styliani Kalantzi
- Biotechnology Laboratory, School of Chemical Engineering, Zografou Campus, National Technical University of Athens, 9 Iroon Polytechniou Str, 15700 Athens, Greece; (S.K.); (A.D.)
| | - Anargiros Dalios
- Biotechnology Laboratory, School of Chemical Engineering, Zografou Campus, National Technical University of Athens, 9 Iroon Polytechniou Str, 15700 Athens, Greece; (S.K.); (A.D.)
| | - Dimitris G. Hatzinikolaou
- Enzyme and Microbial Biotechnology Unit, Department of Biology, Zografou Campus, National and Kapodistrian University of Athens, 15784 Athens, Greece;
- Correspondence: (D.G.H.); (D.M.)
| | - Diomi Mamma
- Biotechnology Laboratory, School of Chemical Engineering, Zografou Campus, National Technical University of Athens, 9 Iroon Polytechniou Str, 15700 Athens, Greece; (S.K.); (A.D.)
- Correspondence: (D.G.H.); (D.M.)
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16
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Bhalla A, Arce J, Ubanwa B, Singh G, Sani RK, Balan V. Thermophilic Geobacillus WSUCF1 Secretome for Saccharification of Ammonia Fiber Expansion and Extractive Ammonia Pretreated Corn Stover. Front Microbiol 2022; 13:844287. [PMID: 35694290 PMCID: PMC9176393 DOI: 10.3389/fmicb.2022.844287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/18/2022] [Indexed: 11/13/2022] Open
Abstract
A thermophilic Geobacillus bacterial strain, WSUCF1 contains different carbohydrate-active enzymes (CAZymes) capable of hydrolyzing hemicellulose in lignocellulosic biomass. We used proteomic, genomic, and bioinformatic tools, and genomic data to analyze the relative abundance of cellulolytic, hemicellulolytic, and lignin modifying enzymes present in the secretomes. Results showed that CAZyme profiles of secretomes varied based on the substrate type and complexity, composition, and pretreatment conditions. The enzyme activity of secretomes also changed depending on the substrate used. The secretomes were used in combination with commercial and purified enzymes to carry out saccharification of ammonia fiber expansion (AFEX)-pretreated corn stover and extractive ammonia (EA)-pretreated corn stover. When WSUCF1 bacterial secretome produced at different conditions was combined with a small percentage of commercial enzymes, we observed efficient saccharification of EA-CS, and the results were comparable to using a commercial enzyme cocktail (87% glucan and 70% xylan conversion). It also opens the possibility of producing CAZymes in a biorefinery using inexpensive substrates, such as AFEX-pretreated corn stover and Avicel, and eliminates expensive enzyme processing steps that are used in enzyme manufacturing. Implementing in-house enzyme production is expected to significantly reduce the cost of enzymes and biofuel processing cost.
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Affiliation(s)
- Aditya Bhalla
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Department of Chemistry, Biology and Health Science, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Great Lakes Bioenergy Center, Michigan State University, East Lansing, MI, United States
| | - Jessie Arce
- Department of Engineering Technology, College of Technology, University of Houston, Houston, TX, United States
| | - Bryan Ubanwa
- Department of Engineering Technology, College of Technology, University of Houston, Houston, TX, United States
| | - Gursharan Singh
- Department of Medical Laboratory Sciences, Lovely Professional University, Phagwara, India
| | - Rajesh K. Sani
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Department of Chemistry, Biology and Health Science, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Venkatesh Balan
- Great Lakes Bioenergy Center, Michigan State University, East Lansing, MI, United States
- Department of Engineering Technology, College of Technology, University of Houston, Houston, TX, United States
- *Correspondence: Venkatesh Balan,
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17
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Zhang R, Lin D, Zhang L, Zhan R, Wang S, Wang K. Molecular and Biochemical Analyses of a Novel Trifunctional Endoxylanase/Endoglucanase/Feruloyl Esterase from the Human Colonic Bacterium Bacteroides intestinalis DSM 17393. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:4044-4056. [PMID: 35316064 DOI: 10.1021/acs.jafc.2c01019] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A novel enzyme Bi76 comprising GH10, E_set_Esterase_N, and CE1 modules was identified, with the highest homology (62.9%) with a bifunctional endoxylanase/feruloyl esterase among characterized enzymes. Interestingly, Bi76 hydrolyzed glucan substrates besides xylans and feruloylated substrates, suggesting that it is the first characterized trifunctional endoxylanase/endoglucanase/feruloyl esterase. Analyses of truncation variants revealed that GH10 and E_set_Esterase_N + CE1 modules encoded endoxylanase/endoglucanase and feruloyl esterase activities, respectively. Synergism analyses indicated that endoxylanase, α-l-arabinofuranosidase, and feruloyl esterase acted cooperatively in releasing ferulic acid (FA) and xylooligosaccharides from feruloylated arabinoxylan. The interdomain synergism of Bi76 overmatched the intermolecular synergism of TM1 and TM2. Importantly, Bi76 exhibited good capacity in producing FA, releasing 5.20, 4.38, 2.12, 1.35, 0.46, and 0.19 mg/g from corn bran, corn cob, wheat bran, corn stover, rice husk, and rice bran, respectively. This study expands the trifunctional endoxylanase/endoglucanase/feruloyl esterase repertoire and demonstrates the great potential of Bi76 in agricultural residue utilization.
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Affiliation(s)
- Ruiqin Zhang
- Research Center of Chinese Herbal Resource Science and Engineering, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education of the People's Republic of China, Guangzhou, Guangdong 510006, People's Republic of China
| | - Dongxia Lin
- Research Center of Chinese Herbal Resource Science and Engineering, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education of the People's Republic of China, Guangzhou, Guangdong 510006, People's Republic of China
| | - Liang Zhang
- Research Center of Chinese Herbal Resource Science and Engineering, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education of the People's Republic of China, Guangzhou, Guangdong 510006, People's Republic of China
| | - Ruoting Zhan
- Research Center of Chinese Herbal Resource Science and Engineering, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education of the People's Republic of China, Guangzhou, Guangdong 510006, People's Republic of China
| | - Sidi Wang
- College of Fundamental Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, People's Republic of China
| | - Kui Wang
- Research Center of Chinese Herbal Resource Science and Engineering, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education of the People's Republic of China, Guangzhou, Guangdong 510006, People's Republic of China
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18
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The Emergence of New Catalytic Abilities in an Endoxylanase from Family GH10 by Removing an Intrinsically Disordered Region. Int J Mol Sci 2022; 23:ijms23042315. [PMID: 35216436 PMCID: PMC8874783 DOI: 10.3390/ijms23042315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 02/05/2023] Open
Abstract
Endoxylanases belonging to family 10 of the glycoside hydrolases (GH10) are versatile in the use of different substrates. Thus, an understanding of the molecular mechanisms underlying substrate specificities could be very useful in the engineering of GH10 endoxylanases for biotechnological purposes. Herein, we analyzed XynA, an endoxylanase that contains a (β/α)8-barrel domain and an intrinsically disordered region (IDR) of 29 amino acids at its amino end. Enzyme activity assays revealed that the elimination of the IDR resulted in a mutant enzyme (XynAΔ29) in which two new activities emerged: the ability to release xylose from xylan, and the ability to hydrolyze p-nitrophenyl-β-d-xylopyranoside (pNPXyl), a substrate that wild-type enzyme cannot hydrolyze. Circular dichroism and tryptophan fluorescence quenching by acrylamide showed changes in secondary structure and increased flexibility of XynAΔ29. Molecular dynamics simulations revealed that the emergence of the pNPXyl-hydrolyzing activity correlated with a dynamic behavior not previously observed in GH10 endoxylanases: a hinge-bending motion of two symmetric regions within the (β/α)8-barrel domain, whose hinge point is the active cleft. The hinge-bending motion is more intense in XynAΔ29 than in XynA and promotes the formation of a wider active site that allows the accommodation and hydrolysis of pNPXyl. Our results open new avenues for the study of the relationship between IDRs, dynamics and activity of endoxylanases, and other enzymes containing (β/α)8-barrel domain.
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19
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Improving the Extraction of Active Ingredients from Medicinal Plants by XynA Modification. J CHEM-NY 2022. [DOI: 10.1155/2022/2483797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Active ingredients of medicinal plants have unique pharmacological and clinical effects. However, conventional extraction technology has many disadvantages, such as long-time and low-efficiency. XynA-assisted extraction may overcome such problems, since the plant cell wall is mainly composed of cellulose. Based on the three-dimensional protein structure, we found the C-terminal domain and N-terminal domain twisted together and resulted in more flexibility. We carried out a series of truncations, with XynA_ΔN36 getting more yields of active ingredients. As shown by HPLC analysis, the efficiencies for extraction of salvianic acid A and berberine from Salvia miltiorrhiza and Phellodendron chinense were increased by approximately 38.14% and 35.20%, respectively, compared with the conventional extraction protocol. The yields of the two compounds reached 2.84 ± 0.05 mg g−1 and 3.52 ± 0.14 mg g−1, respectively. Above all, XynA_ΔN36 can be applied to the extraction of salvianic acid A and berberine, and this study provides a novel enzyme for the extraction technology, which aids rational utilization and quality control of medicinal plants.
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20
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Scheffer G, Rachel NM, Ng KK, Sen A, Gieg LM. Preparation and identification of carboxymethyl cellulose-degrading enzyme candidates for oilfield applications. J Biotechnol 2022; 347:18-25. [DOI: 10.1016/j.jbiotec.2022.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/21/2022] [Accepted: 02/01/2022] [Indexed: 11/28/2022]
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21
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Vacilotto MM, Pellegrini VOA, Sepulchro AGV, Capetti CCDM, Curvelo AAS, Marcondes WF, Arantes V, Polikarpov I. Paludibacter propionicigenes GH10 xylanase as a tool for enzymatic xylooligosaccharides production from heteroxylans. Carbohydr Polym 2022; 275:118684. [PMID: 34742414 DOI: 10.1016/j.carbpol.2021.118684] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/30/2021] [Accepted: 09/16/2021] [Indexed: 12/17/2022]
Abstract
Bioconversion of lignocellulosic biomass into value-added products relies on polysaccharides depolymerization by carbohydrate active enzymes. This work reports biochemical characterization of Paludibacter propionicigenes xylanase from GH10 (PpXyn10A) and its application for enzymatic xylooligosaccharides (XOS) production from commercial heteroxylans and liquor of hydrothermally pretreated corn cobs (PCC). PpXyn10A is tolerant to ethanol and NaCl, and releases xylobiose (X2) and xylotriose (X3) as the main hydrolytic products. The conversion rate of complex substrates into short XOS was approximately 30% for glucuronoxylan and 8.8% for rye arabinoxylan, after only 4 h; while for PCC, PpXyn10A greatly increased unbranched XOS yields. B. adolescentis fermentation with XOS from beechwood glucuronoxylan produced mainly acetic and lactic acids. Structural analysis shows that while the glycone region of PpXyn10A active site is well preserved, the aglycone region has aromatic interactions in the +2 subsite that may explain why PpXyn10A does not release xylose.
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Affiliation(s)
- Milena Moreira Vacilotto
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Vanessa O Arnoldi Pellegrini
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Ana Gabriela Veiga Sepulchro
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Caio C de Mello Capetti
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Antonio Aprigio S Curvelo
- Instituto de Química de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil
| | - Wilian Fioreli Marcondes
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, SP, Brazil
| | - Valdeir Arantes
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, SP, Brazil
| | - Igor Polikarpov
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil.
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22
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Wu D, Wei Z, Mohamed TA, Zheng G, Qu F, Wang F, Zhao Y, Song C. Lignocellulose biomass bioconversion during composting: Mechanism of action of lignocellulase, pretreatment methods and future perspectives. CHEMOSPHERE 2022; 286:131635. [PMID: 34346339 DOI: 10.1016/j.chemosphere.2021.131635] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/24/2021] [Accepted: 07/20/2021] [Indexed: 05/26/2023]
Abstract
Composting is a biodegradation and transformation process that converts lignocellulosic biomass into value-added products, such as humic substances (HSs). However, the recalcitrant nature of lignocellulose hinders the utilization of cellulose and hemicellulose, decreasing the bioconversion efficiency of lignocellulose. Pretreatment is an essential step to disrupt the structure of lignocellulosic biomass. Many pretreatment methods for composting may cause microbial inactivation and death. Thus, the pretreatment methods suitable for composting can promote the degradation and transformation of lignocellulosic biomass. Therefore, this review summarizes the pretreatment methods suitable for composting. Microbial consortium pretreatment, Fenton pretreatment and surfactant-assisted pretreatment for composting may improve the bioconversion process. Microbial consortium pretreatment is a cost-effective pretreatment method to enhance HSs yields during composting. On the other hand, the efficiency of enzyme production during composting is very important for the degradation of lignocellulose, whose action mechanism is unknown. Therefore, this review describes the mechanism of action of lignocellulase, the predominant microbes producing lignocellulase and their related genes. Finally, optimizing pretreatment conditions and increasing enzymatic hydrolysis to improve the quality of composts by controlling suitable microenvironmental factors and core target microbial activities as a research focus in the bioconversion of lignocellulose during composting in the future.
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Affiliation(s)
- Di Wu
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Zimin Wei
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Taha Ahmed Mohamed
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China; Soil, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt
| | - Guangren Zheng
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Fengting Qu
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Feng Wang
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Yue Zhao
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China.
| | - Caihong Song
- College of Life Science, Liaocheng University, Liaocheng, 252000, China
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You S, Zha Z, Li J, Zhang W, Bai Z, Hu Y, Wang X, Chen Y, Chen Z, Wang J, Luo H. Improvement of XYL10C_∆N catalytic performance through loop engineering for lignocellulosic biomass utilization in feed and fuel industries. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:195. [PMID: 34598723 PMCID: PMC8487158 DOI: 10.1186/s13068-021-02044-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/23/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND Xylanase, an important accessory enzyme that acts in synergy with cellulase, is widely used to degrade lignocellulosic biomass. Thermostable enzymes with good catalytic activity at lower temperatures have great potential for future applications in the feed and fuel industries, which have distinct demands; however, the potential of the enzymes is yet to be researched. RESULTS In this study, a structure-based semi-rational design strategy was applied to enhance the low-temperature catalytic performance of Bispora sp. MEY-1 XYL10C_∆N wild-type (WT). Screening and comparisons were performed for the WT and mutant strains. Compared to the WT, the mutant M53S/F54L/N207G exhibited higher specific activity (2.9-fold; 2090 vs. 710 U/mg) and catalytic efficiency (2.8-fold; 1530 vs. 550 mL/s mg) at 40 °C, and also showed higher thermostability (the melting temperature and temperature of 50% activity loss after 30 min treatment increased by 7.7 °C and 3.5 °C, respectively). Compared with the cellulase-only treatment, combined treatment with M53S/F54L/N207G and cellulase increased the reducing sugar contents from corn stalk, wheat bran, and corn cob by 1.6-, 1.2-, and 1.4-folds, with 1.9, 1.2, and 1.6 as the highest degrees of synergy, respectively. CONCLUSIONS This study provides useful insights into the underlying mechanism and methods of xylanase modification for industrial utilization. We identified loop2 as a key functional area affecting the low-temperature catalytic efficiency of GH10 xylanase. The thermostable mutant M53S/F54L/N207G was selected for the highest low-temperature catalytic efficiency and reducing sugar yield in synergy with cellulase in the degradation of different types of lignocellulosic biomass.
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Affiliation(s)
- Shuai You
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212018 People’s Republic of China
| | - Ziqian Zha
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
| | - Jing Li
- Department of Nephrology, Affiliated Hospital of Jiangsu University, Zhenjiang, 212001 People’s Republic of China
| | - Wenxin Zhang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
| | - Zhiyuan Bai
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
| | - Yanghao Hu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
| | - Xue Wang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
| | - Yiwen Chen
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
| | - Zhongli Chen
- Xinyuan Cocoon Silk Group Co., Ltd., Nantong, 226600 People’s Republic of China
| | - Jun Wang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018 People’s Republic of China
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212018 People’s Republic of China
| | - Huiying Luo
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081 People’s Republic of China
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Verma D. Extremophilic Prokaryotic Endoxylanases: Diversity, Applicability, and Molecular Insights. Front Microbiol 2021; 12:728475. [PMID: 34566933 PMCID: PMC8458939 DOI: 10.3389/fmicb.2021.728475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/06/2021] [Indexed: 11/13/2022] Open
Abstract
Extremophilic endoxylanases grabbed attention in recent years due to their applicability under harsh conditions of several industrial processes. Thermophilic, alkaliphilic, and acidophilic endoxylanases found their employability in bio-bleaching of paper pulp, bioconversion of lignocellulosic biomass into xylooligosaccharides, bioethanol production, and improving the nutritious value of bread and other bakery products. Xylanases obtained from extremophilic bacteria and archaea are considered better than fungal sources for several reasons. For example, enzymatic activity under broad pH and temperature range, low molecular weight, cellulase-free activity, and longer stability under extreme conditions of prokaryotic derived xylanases make them a good choice. In addition, a short life span, easy cultivation/harvesting methods, higher yield, and rapid DNA manipulations of bacterial and archaeal cells further reduces the overall cost of the product. This review focuses on the diversity of prokaryotic endoxylanases, their characteristics, and their functional attributes. Besides, the molecular mechanisms of their extreme behavior have also been presented here.
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Affiliation(s)
- Digvijay Verma
- Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
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Banach A, Kuźniar A, Marzec-Grządziel A, Gałązka A, Wolińska A. Phenotype Switching in Metal-Tolerant Bacteria Isolated from a Hyperaccumulator Plant. BIOLOGY 2021; 10:biology10090879. [PMID: 34571755 PMCID: PMC8466758 DOI: 10.3390/biology10090879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/19/2021] [Accepted: 08/28/2021] [Indexed: 11/16/2022]
Abstract
As an adaptation to unfavorable conditions, microorganisms may represent different phenotypes. Azolla filiculoides L. is a hyperaccumulator of pollutants, but the functions of its microbiome have not been well recognized to date. We aimed to reveal the potential of the microbiome for degradation of organic compounds, as well as its potential to promote plant growth in the presence of heavy metals. We applied the BiologTM Phenotypic Microarrays platform to study the potential of the microbiome for the degradation of 96 carbon compounds and stress factors and assayed the hydrolytic potential and auxin production by the microorganisms in the presence of Pb, Cd, Cr (VI), Ni, Ag, and Au. We found various phenotype changes depending on the stress factor, suggesting a possible dual function of the studied microorganisms, i.e., in bioremediation and as a biofertilizer for plant growth promotion. Delftia sp., Staphylococcus sp. and Microbacterium sp. exhibited high efficacy in metabolizing organic compounds. Delftia sp., Achromobacter sp. and Agrobacterium sp. were efficient in enzymatic responses and were characterized by metal tolerant. Since each strain exhibited individual phenotype changes due to the studied stresses, they may all be beneficial as both biofertilizers and bioremediation agents, especially when combined in one biopreparation.
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Affiliation(s)
- Artur Banach
- Department of Biology and Biotechnology of Microorganisms, The John Paul II Catholic University of Lublin, Konstantynów St. 1 I, 20-708 Lublin, Poland; (A.K.); (A.W.)
- Correspondence: ; Tel.: +48-81-454-56-48
| | - Agnieszka Kuźniar
- Department of Biology and Biotechnology of Microorganisms, The John Paul II Catholic University of Lublin, Konstantynów St. 1 I, 20-708 Lublin, Poland; (A.K.); (A.W.)
| | - Anna Marzec-Grządziel
- Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation—State Research Institute, Czartoryskich 8 St., 24-100 Puławy, Poland; (A.M.-G.); (A.G.)
| | - Anna Gałązka
- Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation—State Research Institute, Czartoryskich 8 St., 24-100 Puławy, Poland; (A.M.-G.); (A.G.)
| | - Agnieszka Wolińska
- Department of Biology and Biotechnology of Microorganisms, The John Paul II Catholic University of Lublin, Konstantynów St. 1 I, 20-708 Lublin, Poland; (A.K.); (A.W.)
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Xie W, Yu Q, Zhang R, Liu Y, Cao R, Wang S, Zhan R, Liu Z, Wang K, Wang C. Insights into the Catalytic Mechanism of a Novel XynA and Structure-Based Engineering for Improving Bifunctional Activities. Biochemistry 2021; 60:2071-2083. [PMID: 34156819 DOI: 10.1021/acs.biochem.1c00134] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Xylan and cellulose are the two major constituents of numerous types of lignocellulose. The bifunctional enzyme that exhibits xylanase/cellulase activity has attracted a great deal of attention in biofuel production. Previously, a thermostable GH10 family enzyme (XynA) from Bacillus sp. KW1 was found to degrade both xylan and cellulose. To improve bifunctional activity on the basis of structure, we first determined the crystal structure of XynA at 2.3 Å. Via molecular docking and activity assays, we revealed that Gln250 and His252 were indispensable to bifunctionality, because they could interact with two conserved catalytic residues, Glu182 and Glu280, while bringing the substrate close to the activity pocket. Then we used a structure-based engineering strategy to improve xylanase/cellulase activity. Although no mutants with increased bifunctional activity were obtained after much screening, we found the answer in the N-terminal 36-amino acid truncation of XynA. The activities of XynA_ΔN36 toward beechwood xylan, wheat arabinoxylan, filter paper, and barley β-glucan were significantly increased by 0.47-, 0.53-, 2.46-, and 1.04-fold, respectively. Furthermore, upon application, this truncation released more reducing sugars than the wild type in the degradation of pretreated corn stover and sugar cane bagasse. These results showed the detailed molecular mechanism of the GH10 family bifunctional endoxylanase/cellulase. The basis of these catalytic performances and the screened XynA_ΔN36 provide clues for the further use of XynA in industrial applications.
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Affiliation(s)
- Wei Xie
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Qi Yu
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Ruiqing Zhang
- Research Center of Chinese Herbal Resource Science and Engineering, Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Yun Liu
- Research Center of Chinese Herbal Resource Science and Engineering, Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Ruoting Cao
- Research Center of Chinese Herbal Resource Science and Engineering, Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Sidi Wang
- College of Fundamental Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Ruoting Zhan
- Research Center of Chinese Herbal Resource Science and Engineering, Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Zhongqiu Liu
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Kui Wang
- Research Center of Chinese Herbal Resource Science and Engineering, Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Caiyan Wang
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
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Talens-Perales D, Jiménez-Ortega E, Sánchez-Torres P, Sanz-Aparicio J, Polaina J. Phylogenetic, functional and structural characterization of a GH10 xylanase active at extreme conditions of temperature and alkalinity. Comput Struct Biotechnol J 2021; 19:2676-2686. [PMID: 34093984 PMCID: PMC8148631 DOI: 10.1016/j.csbj.2021.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 01/31/2023] Open
Abstract
Endoxylanases active under extreme conditions of
temperature and alkalinity can replace the use of highly pollutant chemicals in
the pulp and paper industry. Searching for enzymes with these properties, we
carried out a comprehensive bioinformatics study of the GH10 family. The
phylogenetic analysis allowed the construction of a radial cladogram in which
protein sequences putatively ascribed as thermophilic and alkaliphilic appeared
grouped in a well-defined region of the cladogram, designated TAK Cluster. One
among five TAK sequences selected for experimental analysis (Xyn11) showed
extraordinary xylanolytic activity under simultaneous conditions of high
temperature (90 °C) and alkalinity (pH 10.5). Addition of a carbohydrate binding
domain (CBM2) at the C-terminus of the protein sequence further improved the
activity of the enzyme at high pH. Xyn11 structure, which has been solved at
1.8 Å resolution by X-ray crystallography, reveals an unusually high number of
hydrophobic, ionic and hydrogen bond atomic interactions that could account for
the enzyme’s extremophilic nature.
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Affiliation(s)
- David Talens-Perales
- Institute of Agrochemistry and Food Technology, Spanish National Research Council (CSIC), Paterna, Valencia, Spain
| | - Elena Jiménez-Ortega
- Institute of Physical-Chemistry Rocasolano, Spanish National Research Council (CSIC), Madrid, Spain
| | - Paloma Sánchez-Torres
- Institute of Agrochemistry and Food Technology, Spanish National Research Council (CSIC), Paterna, Valencia, Spain
| | - Julia Sanz-Aparicio
- Institute of Physical-Chemistry Rocasolano, Spanish National Research Council (CSIC), Madrid, Spain
| | - Julio Polaina
- Institute of Agrochemistry and Food Technology, Spanish National Research Council (CSIC), Paterna, Valencia, Spain
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Yan S, Xu Y, Yu XW. Rational engineering of xylanase hyper-producing system in Trichoderma reesei for efficient biomass degradation. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:90. [PMID: 33832521 PMCID: PMC8033665 DOI: 10.1186/s13068-021-01943-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/27/2021] [Indexed: 05/27/2023]
Abstract
BACKGROUND Filamentous fungus Trichoderma reesei has been widely used as a workhorse for cellulase and xylanase productions. Xylanase has been reported as the crucial accessory enzyme in the degradation of lignocellulose for higher accessibility of cellulase. In addition, the efficient hydrolysis of xylan needs the co-work of multiple xylanolytic enzymes, which rise an increasing demand for the high yield of xylanase for efficient biomass degradation. RESULTS In this study, a xylanase hyper-producing system in T. reesei was established by tailoring two transcription factors, XYR1 and ACE1, and homologous overexpression of the major endo-xylanase XYNII. The expressed xylanase cocktail contained 5256 U/mL xylanase activity and 9.25 U/mL β-xylosidase (pNPXase) activity. Meanwhile, the transcription level of the xylanolytic genes in the strain with XYR1 overexpressed was upregulated, which was well correlated with the amount of XYR1-binding sites. In addition, the higher expression of associated xylanolytic enzymes would result in more efficient xylan hydrolysis. Besides, 2310-3085 U/mL of xylanase activities were achieved using soluble carbon source, which was more efficient and economical than the traditional strategy of xylan induction. Unexpectedly, deletion of ace1 in C30OExyr1 did not give any improvement, which might be the result of the disturbed function of the complex formed between ACE1 and XYR1. The enzymatic hydrolysis of alkali pretreated corn stover using the crude xylanase cocktails as accessory enzymes resulted in a 36.64% increase in saccharification efficiency with the ratio of xylanase activity vs FPase activity at 500, compared to that using cellulase alone. CONCLUSIONS An efficient and economical xylanase hyper-producing platform was developed in T. reesei RUT-C30. The novel platform with outstanding ability for crude xylanase cocktail production would greatly fit in biomass degradation and give a new perspective of further engineering in T. reesei for industrial purposes.
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Affiliation(s)
- Su Yan
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Yan Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Xiao-Wei Yu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.
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Rashid R, Sohail M. Xylanolytic Bacillus species for xylooligosaccharides production: a critical review. BIORESOUR BIOPROCESS 2021; 8:16. [PMID: 38650226 PMCID: PMC10991489 DOI: 10.1186/s40643-021-00369-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/09/2021] [Indexed: 02/06/2023] Open
Abstract
The capacity of different Bacillus species to produce large amounts of extracellular enzymes and ability to ferment various substrates at a wide range of pH and temperature has placed them among the most promising hosts for the industrial production of many improved and novel products. The global interest in prebiotics, for example, xylooligosaccharides (XOs) is ever increasing, rousing the quest for various forms with expanded productivity. This article provides an overview of xylanase producing bacilli, with more emphasis on their capacity to be used in the production of the XOs, followed by the purification strategies, characteristics and application of XOs from bacilli. The large-scale production of XOs is carried out from a number of xylan-rich lignocellulosic materials by chemical or enzymatic hydrolysis followed by purification through chromatography, vacuum evaporation, solvent extraction or membrane separation methods. Utilization of XOs in the production of functional products as food ingredients brings well-being to individuals by improving defense system and eliminating pathogens. In addition to the effects related to health, a variety of other biological impacts have also been discussed.
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Affiliation(s)
- Rozina Rashid
- Department of Microbiology, University of Karachi, Karachi, 75270, Pakistan
- Department of Microbiology, University of Balochistan, Quetta, Pakistan
| | - Muhammad Sohail
- Department of Microbiology, University of Karachi, Karachi, 75270, Pakistan.
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Conversion of Wheat Bran to Xylanases and Dye Adsorbent by Streptomyces thermocarboxydus. Polymers (Basel) 2021; 13:polym13020287. [PMID: 33477336 PMCID: PMC7830096 DOI: 10.3390/polym13020287] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 11/16/2022] Open
Abstract
Agro-byproducts can be utilized as effective and low-cost nutrient sources for microbial fermentation to produce a variety of usable products. In this study, wheat bran powder (WBP) was found to be the most effective carbon source for xylanase production by Streptomyces thermocarboxydus TKU045. The optimal media for xylanase production was 2% (w/v) WBP, 1.50% (w/v) KNO3, 0.05% (w/v) MgSO4, and 0.10% (w/v) K2HPO4, and the optimal culture conditions were 50 mL (in a 250 mL-volume Erlenmeyer flask), initial pH 9.0, 37 °C, 125 rpm, and 48 h. Accordingly, the highest xylanase activity was 6.393 ± 0.130 U/mL, 6.9-fold higher than that from un-optimized conditions. S. thermocarboxydus TKU045 secreted at least four xylanases with the molecular weights of >180, 36, 29, and 27 kDa when cultured on the WBP-containing medium. The enzyme cocktail produced by S. thermocarboxydus TKU045 was optimally active over a broad range of temperature and pH (40–70 °C and pH 5–8, respectively) and could hydrolyze birchwood xylan to produce xylobiose as the major product. The obtained xylose oligosaccharide (XOS) were investigated for 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and the growth effect of lactic acid bacteria. Finally, the solid waste from the WBP fermentation using S. thermocarboxydus TKU045 revealed the high adsorption of Congo red, Red 7, and Methyl blue. Thus, S. thermocarboxydus TKU045 could be a potential strain to utilize wheat bran to produce xylanases for XOS preparation and dye adsorbent.
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Lai Z, Zhou C, Ma X, Xue Y, Ma Y. Enzymatic characterization of a novel thermostable and alkaline tolerant GH10 xylanase and activity improvement by multiple rational mutagenesis strategies. Int J Biol Macromol 2020; 170:164-177. [PMID: 33352153 DOI: 10.1016/j.ijbiomac.2020.12.137] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 11/15/2022]
Abstract
Thermo-alkaline xylanases are widely applied in paper pulping industry. In this study, a novel thermostable and alkaline tolerant GH10 xylanase (Xyn30Y5) gene from alkaliphilic Bacillus sp. 30Y5 was cloned and the surface-layer homology (SLH) domains truncated enzyme (Xyn30Y5-SLH) was expressed in Escherichia coli. The purified Xyn30Y5-SLH was most active at 70 °C and pH 7.0 and showed the highest specific activity of 349.4 U mg-1. It retained more than 90% activity between pH 6.0 to 9.5 and was stable at pH 6.0-10.0. To improve the activity, 47 mutants were designed based on eight rational strategies and 21 mutants showed higher activity. By combinatorial mutagenesis, the best mutant 3B demonstrated specific activity of 1016.8 U mg-1 with a doubled catalytic efficiency (kcat/Km) and RA601/2h value, accompanied by optimal pH shift to 8.0. The molecular dynamics simulation analysis indicated that the increase of flexibility of α5 helix and loop7 located near to the catalytic residues is likely responsible for its activity improvement. And the decrease of flexibility of the most unstable regions is vital for the thermostablity improvement. This work provided not only a novel thermostable and alkaline tolerant xylanase with industrial application potential but also an effective mutagenesis strategy for xylanase activity improvement.
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Affiliation(s)
- Zhihua Lai
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Cheng Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xiaochen Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanfen Xue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanhe Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; National Engineering Laboratory for Industrial Enzymes, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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Chen X, Wang X, Liu Y, Zhang R, Zhang L, Zhan R, Wang S, Wang K. Biochemical analyses of a novel thermostable GH5 endo β-1,4-mannanase with minor β-1,4-glucosidic cleavage activity from Bacillus sp. KW1 and its synergism with a commercial α-galactosidase on galactomannan hydrolysis. Int J Biol Macromol 2020; 166:778-788. [PMID: 33144255 DOI: 10.1016/j.ijbiomac.2020.10.235] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/07/2020] [Accepted: 10/30/2020] [Indexed: 11/17/2022]
Abstract
A novel GH5 endo-1,4-β-mannanase (BaMan5A) was identified from Bacillus sp. KW1, it shares the highest sequence identity (86%) with another characterized Bacillus endo-1,4-β-mannanase. The recombinant BaMan5A displayed maximum activity at pH 7.0 and 70 °C, it was stable at a broad pH range (pH 3.5-11.0) after 12-h incubation at 25 °C, and exhibited good thermostability, retaining about 100% and 85% activity after incubating at 60 °C for 12 h and 65 °C for 8 h, respectively. The results of polysaccharide hydrolysis revealed that the enzyme can only hydrolyze mannan substrates, including carob galactomannan, konjac glucomannan, 1,4-β-D-mannan, locust bean gum, and guar gum, yielding mannose, mannobiose, mannotriose, and some other oligosaccharides. The best substrate was carob galactomannan, the corresponding specific activity and Km value were 10,886 μmol/min/μmol and 3.31 mg/mL, respectively. Interestingly, BaMan5A was capable to hydrolyze both manno-oligosaccharides and cello-oligosaccharides, including mannotetraose, mannopentaose, mannohexaose, cellopentaose and cellohexaose. Furthermore, BaMan5A acted synergistically with a commercial α-galactosidase (CbAgal) on galactomannan depolymerization, a best synergy degree of 1.58 was achieved after optimizing enzyme ratios. This study not only expands the diversity of Bacillus GH5 β-mannanase, but also discloses the potential of BaMan5A in industrial application.
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Affiliation(s)
- Xi Chen
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, PR China; Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou, PR China; Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, PR China
| | - Xinhai Wang
- Department of General Surgery, Huashan Hospital of Fudan University, Shanghai, PR China
| | - Yun Liu
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, PR China; Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou, PR China; Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, PR China
| | - Ruiqin Zhang
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, PR China; Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou, PR China; Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, PR China
| | - Liang Zhang
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, PR China; Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou, PR China; Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, PR China
| | - Ruoting Zhan
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, PR China; Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou, PR China; Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, PR China
| | - Sidi Wang
- College of Fundamental Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, PR China
| | - Kui Wang
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, PR China; Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou, PR China; Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, PR China.
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Han C, Yang R, Sun Y, Liu M, Zhou L, Li D. Identification and Characterization of a Novel Hyperthermostable Bifunctional Cellobiohydrolase- Xylanase Enzyme for Synergistic Effect With Commercial Cellulase on Pretreated Wheat Straw Degradation. Front Bioeng Biotechnol 2020; 8:296. [PMID: 32328483 PMCID: PMC7160368 DOI: 10.3389/fbioe.2020.00296] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 03/20/2020] [Indexed: 12/19/2022] Open
Abstract
The novel cellobiohydrolase gene ctcel7 was identified from Chaetomium thermophilum, and its recombinant protein CtCel7, a member of glycoside hydrolase family 7, was heterologously expressed in Pichia pastoris and biochemically characterized. Compared with commercial hydrolases, purified CtCel7 exhibited superior bifunctional cellobiohydrolase and xylanase activities against microcrystalline cellulose and xylan, respectively, under optimal conditions of 60°C and pH 4.0. Moreover, CtCel7 displayed remarkable thermostability with over 90% residual activity after heat (60°C) treatment for 180 min. CtCel7 was insensitive to most detected cations and reagents and preferentially cleaved the β-1,4-glycosidic bond to generate oligosaccharides through the continuous saccharification of lignocellulosic substrates, which are crucial for various practical applications. Notably, the hydrolysis effect of a commercial cellulase cocktail on pretreated wheat straw was substantively improved by its combination with CtCel7. Taken together, these excellent properties distinguish CtCel7 as a robust candidate for the biotechnological production of biofuels and biobased chemicals.
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Affiliation(s)
- Chao Han
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Ruirui Yang
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Yanxu Sun
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Mengyu Liu
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Lifan Zhou
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Duochuan Li
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
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Characterization of a novel xylanase from an extreme temperature hot spring metagenome for xylooligosaccharide production. Appl Microbiol Biotechnol 2020; 104:4889-4901. [DOI: 10.1007/s00253-020-10562-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/12/2020] [Accepted: 03/20/2020] [Indexed: 10/24/2022]
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Gloster TM. Exploitation of carbohydrate processing enzymes in biocatalysis. Curr Opin Chem Biol 2020; 55:180-188. [PMID: 32203896 DOI: 10.1016/j.cbpa.2020.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/26/2020] [Accepted: 01/31/2020] [Indexed: 12/14/2022]
Abstract
Exploitation of enzymes in biocatalytic processes provides scope both in the synthesis and degradation of molecules. Enzymes have power not only in their catalytic efficiency, but their chemoselectivity, regioselectivity, and stereoselectivity means the reactions they catalyze are precise and reproducible. Focusing on carbohydrate processing enzymes, this review covers advances in biocatalysis involving carbohydrates over the last 2-3 years. Given the notorious difficulties in the chemical synthesis of carbohydrates, the use of enzymes for synthesis has potential for significant impact in the future. The use of catabolic enzymes in the degradation of biomass, which can be exploited in the production of biofuels to provide a sustainable and greener source of energy, and the synthesis of molecules that have a range of applications including in the pharmaceutical and food industries will be explored.
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Affiliation(s)
- Tracey M Gloster
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK.
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Efficient Enzymatic Hydrolysis of Biomass Hemicellulose in the Absence of Bulk Water. Molecules 2019; 24:molecules24234206. [PMID: 31756935 PMCID: PMC6930478 DOI: 10.3390/molecules24234206] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 01/20/2023] Open
Abstract
Current enzymatic methods for hemicellulosic biomass depolymerization are solution-based, typically require a harsh chemical pre-treatment of the material and large volumes of water, yet lack in efficiency. In our study, xylanase (E.C. 3.2.1.8) from Thermomyces lanuginosus is used to hydrolyze xylans from different sources. We report an innovative enzymatic process which avoids the use of bulk aqueous, organic or inorganic solvent, and enables hydrolysis of hemicellulose directly from chemically untreated biomass, to low-weight, soluble oligoxylosaccharides in >70% yields.
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A novel glycoside hydrolase family 42 enzyme with bifunctional β-galactosidase and α-L-arabinopyranosidase activities and its synergistic effects with cognate glycoside hydrolases in plant polysaccharides degradation. Int J Biol Macromol 2019; 140:129-139. [DOI: 10.1016/j.ijbiomac.2019.08.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/04/2019] [Accepted: 08/05/2019] [Indexed: 11/21/2022]
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Ellilä S, Bromann P, Nyyssönen M, Itävaara M, Koivula A, Paulin L, Kruus K. Cloning of novel bacterial xylanases from lignocellulose-enriched compost metagenomic libraries. AMB Express 2019; 9:124. [PMID: 31385056 PMCID: PMC6682842 DOI: 10.1186/s13568-019-0847-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/25/2019] [Indexed: 11/18/2022] Open
Abstract
Xylanases are in important class of industrial enzymes that are essential for the complete hydrolysis of lignocellulosic biomass into fermentable sugars. In the present study, we report the cloning of novel xylanases with interesting properties from compost metagenomics libraries. Controlled composting of lignocellulosic materials was used to enrich the microbial population in lignocellulolytic organisms. DNA extracted from the compost samples was used to construct metagenomics libraries, which were screened for xylanase activity. In total, 40 clones exhibiting xylanase activity were identified and the thermostability of the discovered xylanases was assayed directly from the library clones. Five genes, including one belonging to the more rare family GH8, were selected for subcloning and the enzymes were expressed in recombinant form in E. coli. Preliminary characterization of the metagenome-derived xylanases revealed interesting properties of the novel enzymes, such as high thermostability and specific activity, and differences in hydrolysis profiles. One enzyme was found to perform better than a standard Trichoderma reesei xylanase in the hydrolysis of lignocellulose at elevated temperatures.
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