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Lin S, Hunt CJ, Holck J, Brask J, Krogh KBRM, Meyer AS, Wilkens C, Agger JW. Fungal feruloyl esterases can catalyze release of diferulic acids from complex arabinoxylan. Int J Biol Macromol 2023; 232:123365. [PMID: 36690236 DOI: 10.1016/j.ijbiomac.2023.123365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/10/2023] [Accepted: 01/17/2023] [Indexed: 01/22/2023]
Abstract
Feruloyl esterases (FAEs, EC 3.1.1.73) catalyze the hydrolytic cleavage of ester bonds between feruloyl and arabinosyl moieties in arabinoxylans. Recently, we discovered that two bacterial FAEs could catalyze release of diferulic acids (diFAs) from highly substituted, cross-linked corn bran arabinoxylan. Here, we show that several fungal FAEs, notably AnFae1 (Aspergillus niger), AoFae1 (A. oryzae), and MgFae1 (Magnaporthe oryzae (also known as M. grisae)) also catalyze liberation of diFAs from complex arabinoxylan. By comparing the enzyme kinetics of diFA release to feruloyl esterase activity of the enzymes on methyl- and arabinosyl-ferulate substrates we demonstrate that the diFA release activity cannot be predicted from the activity of the enzymes on these synthetic substrates. A detailed structure-function analysis, based on AlphaFold2 modeled enzyme structures and docking with the relevant di-feruloyl ligands, reveal how distinct differences in the active site topology and surroundings may explain the diFA releasing action of the enzymes. Interestingly, the analysis also unveils that the carbohydrate binding module of the MgFae1 may play a key role in the diFA releasing ability of this enzyme. The findings contribute further understanding of the function of FAEs in the deconstruction of complex arabinoxylans and provide new opportunities for enzyme assisted upgrading of complex bran arabinoxylans.
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Affiliation(s)
- Shang Lin
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800 Kgs. Lyngby, Denmark
| | - Cameron J Hunt
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800 Kgs. Lyngby, Denmark
| | - Jesper Holck
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800 Kgs. Lyngby, Denmark
| | - Jesper Brask
- Novozymes A/S, Biologiens Vej 2, DK-2800 Kgs. Lyngby, Denmark
| | | | - Anne S Meyer
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800 Kgs. Lyngby, Denmark.
| | - Casper Wilkens
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800 Kgs. Lyngby, Denmark
| | - Jane W Agger
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800 Kgs. Lyngby, Denmark
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López-López A, Santiago-Hernández A, Cayetano-Cruz M, García-Huante Y, Campos JE, Bustos-Jaimes I, Marsch-Moreno R, Cano-Ramírez C, Benitez-Cardoza CG, Hidalgo-Lara ME. TtCel7A: A Native Thermophilic Bifunctional Cellulose/Xylanase Exogluclanase from the Thermophilic Biomass-Degrading Fungus Thielavia terrestris Co3Bag1, and Its Application in Enzymatic Hydrolysis of Agroindustrial Derivatives. J Fungi (Basel) 2023; 9. [PMID: 36836267 DOI: 10.3390/jof9020152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
The biomass-degrading thermophilic ascomycete fungus Thielavia terrestris Co3Bag1 produces TtCel7A, a native bifunctional cellulase/xylanase GH7 family. The purified TtCel7A, with an estimated molecular weight of 71 kDa, was biochemically characterized. TtCel7A displayed an optimal pH of 5.5 for both activities and an optimal temperature of 60 and 50 °C for cellulolytic and xylanolytic activities, respectively. The half-lives determined for cellulase activity were 140, 106, and 41 min at 50, 60, and 70 °C, respectively, whereas the half-lives observed for xylanase activity were 24, 10, and 1.4 h at 50, 60, and 70 °C, respectively. The KM and Vmax values were 3.12 mg/mL and 50 U/mg for cellulase activity and 0.17 mg/mL and 42.75 U/mg for xylanase activity. Circular dichroism analysis suggests changes in the secondary structure of TtCel7A in the presence of CMC as the substrate, whereas no modifications were observed with beechwood xylan. TtCel7A displayed the excellent capability to hydrolyze CMC, beechwood xylan, and complex substrates such as oat bran, wheat bran, and sugarcane bagasse, with glucose and cellobiose being the main products released; also, slightly less endo cellulase and xylanase activities were observed. Thus, suggesting TtCel7A has an exo- and endomode of action. Based on the characteristics of the enzyme, it might be considered a good candidate for industrial applications.
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Ajeje SB, Hu Y, Song G, Peter SB, Afful RG, Sun F, Asadollahi MA, Amiri H, Abdulkhani A, Sun H. Thermostable Cellulases / Xylanases From Thermophilic and Hyperthermophilic Microorganisms: Current Perspective. Front Bioeng Biotechnol 2021; 9:794304. [PMID: 34976981 PMCID: PMC8715034 DOI: 10.3389/fbioe.2021.794304] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/02/2021] [Indexed: 12/13/2022] Open
Abstract
The bioconversion of lignocellulose into monosaccharides is critical for ensuring the continual manufacturing of biofuels and value-added bioproducts. Enzymatic degradation, which has a high yield, low energy consumption, and enhanced selectivity, could be the most efficient and environmentally friendly technique for converting complex lignocellulose polymers to fermentable monosaccharides, and it is expected to make cellulases and xylanases the most demanded industrial enzymes. The widespread nature of thermophilic microorganisms allows them to proliferate on a variety of substrates and release substantial quantities of cellulases and xylanases, which makes them a great source of thermostable enzymes. The most significant breakthrough of lignocellulolytic enzymes lies in lignocellulose-deconstruction by enzymatic depolymerization of holocellulose into simple monosaccharides. However, commercially valuable thermostable cellulases and xylanases are challenging to produce in high enough quantities. Thus, the present review aims at giving an overview of the most recent thermostable cellulases and xylanases isolated from thermophilic and hyperthermophilic microbes. The emphasis is on recent advancements in manufacturing these enzymes in other mesophilic host and enhancement of catalytic activity as well as thermostability of thermophilic cellulases and xylanases, using genetic engineering as a promising and efficient technology for its economic production. Additionally, the biotechnological applications of thermostable cellulases and xylanases of thermophiles were also discussed.
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Affiliation(s)
- Samaila Boyi Ajeje
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yun Hu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Guojie Song
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Sunday Bulus Peter
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Richmond Godwin Afful
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Fubao Sun
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Mohammad Ali Asadollahi
- Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Hamid Amiri
- Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Ali Abdulkhani
- Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran, Karaj, Iran
| | - Haiyan Sun
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
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Steindorff AS, Serra LA, Formighieri EF, de Faria FP, Poças-Fonseca MJ, de Almeida JRM. Insights into the Lignocellulose-Degrading Enzyme System of Humicola grisea var. thermoidea Based on Genome and Transcriptome Analysis. Microbiol Spectr 2021; 9:e0108821. [PMID: 34523973 DOI: 10.1128/Spectrum.01088-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Humicola grisea var. thermoidea is a thermophilic ascomycete and important enzyme producer that has an efficient enzymatic system with a broad spectrum of thermostable carbohydrate-active (CAZy) enzymes. These enzymes can be employed in lignocellulose biomass deconstruction and other industrial applications. In this work, the genome of H. grisea var. thermoidea was sequenced. The acquired sequence reads were assembled into a total length of 28.75 Mbp. Genome features correlate with what was expected for thermophilic Sordariomycetes. The transcriptomic data showed that sugarcane bagasse significantly upregulated genes related to primary metabolism and polysaccharide deconstruction, especially hydrolases, at both pH 5 and pH 8. However, a number of exclusive and shared genes between the pH values were found, especially at pH 8. H. grisea expresses an average of 211 CAZy enzymes (CAZymes), which are capable of acting in different substrates. The top upregulated genes at both pH values represent CAZyme-encoding genes from different classes, including acetylxylan esterase, endo-1,4-β-mannosidase, exoglucanase, and endoglucanase genes. For the first time, the arsenal that the thermophilic fungus H. grisea var. thermoidea possesses to degrade the lignocellulosic biomass is shown. Carbon source and pH are of pivotal importance in regulating gene expression in this organism, and alkaline pH is a key regulatory factor for sugarcane bagasse hydrolysis. This work paves the way for the genetic manipulation and robust biotechnological applications of this fungus. IMPORTANCE Most studies regarding the use of fungi as enzyme producers for biomass deconstruction have focused on mesophile species, whereas the potential of thermophiles has been evaluated less. This study revealed, through genome and transcriptome analyses, the genetic repertoire of the biotechnological relevant thermophile fungus Humicola grisea. Comparative genomics helped us to further understand the biology and biotechnological potential of H. grisea. The results demonstrate that this fungus possesses an arsenal of carbohydrate-active (CAZy) enzymes to degrade the lignocellulosic biomass. Indeed, it expresses more than 200 genes encoding CAZy enzymes when cultivated in sugarcane bagasse. Carbon source and pH are key factors for regulating the gene expression in this organism. This work shows, for the first time, the great potential of H. grisea as an enzyme producer and a gene donor for biotechnological applications and provides the base for the genetic manipulation and robust biotechnological applications of this fungus.
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Ivaldi C, Daou M, Vallon L, Bisotto A, Haon M, Garajova S, Bertrand E, Faulds CB, Sciara G, Jacotot A, Marchand C, Hugoni M, Rakotoarivonina H, Rosso MN, Rémond C, Luis P, Record E. Screening New Xylanase Biocatalysts from the Mangrove Soil Diversity. Microorganisms 2021; 9:microorganisms9071484. [PMID: 34361919 PMCID: PMC8306085 DOI: 10.3390/microorganisms9071484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/16/2022] Open
Abstract
Mangrove sediments from New Caledonia were screened for xylanase sequences. One enzyme was selected and characterized both biochemically and for its industrial potential. Using a specific cDNA amplification method coupled with a MiSeq sequencing approach, the diversity of expressed genes encoding GH11 xylanases was investigated beneath Avicenia marina and Rhizophora stylosa trees during the wet and dry seasons and at two different sediment depths. GH11 xylanase diversity varied more according to tree species and season, than with respect to depth. One complete cDNA was selected (OFU29) and expressed in Pichia pastoris. The corresponding enzyme (called Xyn11-29) was biochemically characterized, revealing an optimal activity at 40–50 °C and at a pH of 5.5. Xyn11-29 was stable for 48 h at 35 °C, with a half-life of 1 h at 40 °C and in the pH range of 5.5–6. Xyn11-29 exhibited a high hydrolysis capacity on destarched wheat bran, with 40% and 16% of xylose and arabinose released after 24 h hydrolysis. Its activity on wheat straw was lower, with a release of 2.8% and 6.9% of xylose and arabinose, respectively. As the protein was isolated from mangrove sediments, the effect of sea salt on its activity was studied and discussed.
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Affiliation(s)
- Corinne Ivaldi
- INRAE, FARE, UMR A 614, Chaire AFERE, Université de Reims Champagne Ardenne, 51097 Reims, France; (C.I.); (H.R.); (C.R.)
| | - Mariane Daou
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
- Department of Chemistry, Khalifa University, Abu Dhabi 127788, United Arab Emirates
| | - Laurent Vallon
- CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Université Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France; (L.V.); (M.H.); (P.L.)
| | - Alexandra Bisotto
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Mireille Haon
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Sona Garajova
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Emmanuel Bertrand
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Craig B. Faulds
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Giuliano Sciara
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Adrien Jacotot
- Institut de Recherche pour le Développement (IRD), IMPMC, UPMC, CNRS, MNHN, 98851 Noumea, New Caledonia, France; (A.J.); (C.M.)
- ISEA, Université de la Nouvelle-Calédonie, EA 7484, 8 BPR4, 98851 Noumea, New Caledonia, France
- CNRS, BRGM, ISTO, UMR 7327, Université d’Orléans, 45071 Orléans, France
| | - Cyril Marchand
- Institut de Recherche pour le Développement (IRD), IMPMC, UPMC, CNRS, MNHN, 98851 Noumea, New Caledonia, France; (A.J.); (C.M.)
- ISEA, Université de la Nouvelle-Calédonie, EA 7484, 8 BPR4, 98851 Noumea, New Caledonia, France
| | - Mylène Hugoni
- CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Université Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France; (L.V.); (M.H.); (P.L.)
| | - Harivony Rakotoarivonina
- INRAE, FARE, UMR A 614, Chaire AFERE, Université de Reims Champagne Ardenne, 51097 Reims, France; (C.I.); (H.R.); (C.R.)
| | - Marie-Noëlle Rosso
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
| | - Caroline Rémond
- INRAE, FARE, UMR A 614, Chaire AFERE, Université de Reims Champagne Ardenne, 51097 Reims, France; (C.I.); (H.R.); (C.R.)
| | - Patricia Luis
- CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Université Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France; (L.V.); (M.H.); (P.L.)
| | - Eric Record
- INRAE, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille Université, 13288 Marseille, France; (M.D.); (A.B.); (M.H.); (S.G.); (E.B.); (C.B.F.); (G.S.); (M.-N.R.)
- Correspondence:
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Tõlgo M, Hüttner S, Rugbjerg P, Thuy NT, Thanh VN, Larsbrink J, Olsson L. Genomic and transcriptomic analysis of the thermophilic lignocellulose-degrading fungus Thielavia terrestris LPH172. Biotechnol Biofuels 2021; 14:131. [PMID: 34082802 PMCID: PMC8176577 DOI: 10.1186/s13068-021-01975-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 05/18/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Biomass-degrading enzymes with improved activity and stability can increase substrate saccharification and make biorefineries economically feasible. Filamentous fungi are a rich source of carbohydrate-active enzymes (CAZymes) for biomass degradation. The newly isolated LPH172 strain of the thermophilic Ascomycete Thielavia terrestris has been shown to possess high xylanase and cellulase activities and tolerate low pH and high temperatures. Here, we aimed to illuminate the lignocellulose-degrading machinery and novel carbohydrate-active enzymes in LPH172 in detail. RESULTS We sequenced and analyzed the 36.6-Mb genome and transcriptome of LPH172 during growth on glucose, cellulose, rice straw, and beechwood xylan. 10,128 predicted genes were found in total, which included 411 CAZy domains. Compared to other fungi, auxiliary activity (AA) domains were particularly enriched. A higher GC content was found in coding sequences compared to the overall genome, as well as a high GC3 content, which is hypothesized to contribute to thermophilicity. Primarily auxiliary activity (AA) family 9 lytic polysaccharide monooxygenase (LPMO) and glycoside hydrolase (GH) family 7 glucanase encoding genes were upregulated when LPH172 was cultivated on cellulosic substrates. Conventional hemicellulose encoding genes (GH10, GH11 and various CEs), as well as AA9 LPMOs, were upregulated when LPH172 was cultivated on xylan. The observed co-expression and co-upregulation of genes encoding AA9 LPMOs, other AA CAZymes, and (hemi)cellulases point to a complex and nuanced degradation strategy. CONCLUSIONS Our analysis of the genome and transcriptome of T. terrestris LPH172 elucidates the enzyme arsenal that the fungus uses to degrade lignocellulosic substrates. The study provides the basis for future characterization of potential new enzymes for industrial biomass saccharification.
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Affiliation(s)
- Monika Tõlgo
- Wallenberg Wood Science Centre, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
- Division of Industrial Biotechnology, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Silvia Hüttner
- Wallenberg Wood Science Centre, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
- Division of Industrial Biotechnology, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Peter Rugbjerg
- Division of Industrial Biotechnology, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Nguyen Thanh Thuy
- Center for Industrial Microbiology, Food Industries Research Institute, Thanh Xuan, Hanoi, Vietnam
| | - Vu Nguyen Thanh
- Center for Industrial Microbiology, Food Industries Research Institute, Thanh Xuan, Hanoi, Vietnam
| | - Johan Larsbrink
- Wallenberg Wood Science Centre, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
- Division of Industrial Biotechnology, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Lisbeth Olsson
- Wallenberg Wood Science Centre, Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
- Division of Industrial Biotechnology, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
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Camargo S, Mulinari EJ, de Almeida LR, Bernardes A, Prade RA, Garcia W, Segato F, Muniz JR. Functional and structural characterization of an α-ʟ-arabinofuranosidase from Thermothielavioides terrestris and its exquisite domain-swapped β-propeller fold crystal packing. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2020; 1868:140533. [DOI: 10.1016/j.bbapap.2020.140533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 07/25/2020] [Accepted: 08/12/2020] [Indexed: 12/24/2022]
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Long L, Sun L, Lin Q, Ding S, St John FJ. Characterization and functional analysis of two novel thermotolerant α-L-arabinofuranosidases belonging to glycoside hydrolase family 51 from Thielavia terrestris and family 62 from Eupenicillium parvum. Appl Microbiol Biotechnol 2020; 104:8719-8733. [PMID: 32880690 PMCID: PMC7502447 DOI: 10.1007/s00253-020-10867-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 08/06/2020] [Accepted: 08/26/2020] [Indexed: 11/26/2022]
Abstract
Abstract Arabinofuranose substitutions on xylan are known to interfere with enzymatic hydrolysis of this primary hemicellulose. In this work, two novel α-l-arabinofuranosidases (ABFs), TtABF51A from Thielavia terrestris and EpABF62C from Eupenicillium parvum, were characterized and functionally analyzed. From sequences analyses, TtABF51A and EpABF62C belong to glycoside hydrolase (GH) families 51 and 62, respectively. Recombinant TtABF51A showed high activity on 4-nitrophenyl-α-l-arabinofuranoside (83.39 U/mg), low-viscosity wheat arabinoxylan (WAX, 39.66 U/mg), high-viscosity rye arabinoxylan (RAX, 32.24 U/mg), and sugarbeet arabinan (25.69 U/mg), while EpABF62C preferred to degrade arabinoxylan. For EpABF62C, the rate of hydrolysis of RAX (94.10 U/mg) was 2.1 times that of WAX (45.46 U/mg). The optimal pH and reaction temperature for the two enzymes was between 4.0 and 4.5 and 65 °C, respectively. Calcium played an important role in the thermal stability of EpABF62C. TtABF51A and EpABF62C showed the highest thermal stabilities at pH 4.5 or 5.0, respectively. At their optimal pHs, TtABF51A and EpABF62C retained greater than 80% of their initial activities after incubation at 55 °C for 96 h or 144 h, respectively. 1H NMR analysis indicated that the two enzymes selectively removed arabinose linked to C-3 of mono-substituted xylose residues in WAX. Compared with the singular application of the GH10 xylanase EpXYN1 from E. parvum, co-digestions of WAX including TtABF51A and/or EpABF62C released 2.49, 3.38, and 4.81 times xylose or 3.38, 1.65, and 2.57 times of xylobiose, respectively. Meanwhile, the amount of arabinose released from WAX by TtABF51A with EpXYN1 was 2.11 times the amount with TtABF51A alone. Key points • Two novel α-l-arabinofuranosidases (ABFs) displayed high thermal stability. • The thermal stability of GH62 family EpABF62C was dependent on calcium. • Buffer pH affects the thermal stability of the two ABFs. • Both ABFs enhance the hydrolysis of WAX by a GH10 xylanase. Electronic supplementary material The online version of this article (10.1007/s00253-020-10867-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Liangkun Long
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive, Madison, WI, 53726, USA
| | - Lu Sun
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China
| | - Qunying Lin
- Nanjing Institute for the Comprehensive Utilization of Wild Plants, Nanjing, 211111, China
| | - Shaojun Ding
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
| | - Franz J St John
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive, Madison, WI, 53726, USA.
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Zhu N, Jin H, Kong X, Zhu Y, Ye X, Xi Y, Du J, Li B, Lou M, Shah GM. Improving the fermentable sugar yields of wheat straw by high-temperature pre-hydrolysis with thermophilic enzymes of Malbranchea cinnamomea. Microb Cell Fact 2020; 19:149. [PMID: 32711527 DOI: 10.1186/s12934-020-01408-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 07/20/2020] [Indexed: 12/23/2022] Open
Abstract
Background Enzymatic hydrolysis is a key step in the conversion of lignocellulosic polysaccharides to fermentable sugars for the production of biofuels and high-value chemicals. However, current enzyme preparations from mesophilic fungi are deficient in their thermostability and biomass-hydrolyzing efficiency at high temperatures. Thermophilic fungi represent promising sources of thermostable and highly active enzymes for improving the biomass-to-sugar conversion process. Here we present a comprehensive study on the lignocellulosic biomass-degrading ability and enzyme system of thermophilic fungus Malbranchea cinnamomea N12 and the application of its enzymes in the synergistic hydrolysis of lignocellulosic biomass. Results Malbranchea cinnamomea N12 was capable of utilizing untreated wheat straw to produce high levels of xylanases and efficiently degrading lignocellulose under thermophilic conditions. Temporal analysis of the wheat straw-induced secretome revealed that M. cinnamomea N12 successively degraded the lignocellulosic polysaccharides through sequential secretion of enzymes targeting xylan and cellulose. Xylanase-enriched cocktail from M. cinnamomea N12 was more active on native and alkali‑pretreated wheat straw than the commercial xylanases from Trichoderma reesei over temperatures ranging from 40 to 75 °C. Integration of M. cinnamomea N12 enzymes with the commercial cellulase preparation increased the glucose and xylose yields of alkali‑pretreated wheat straw by 32 and 166%, respectively, with pronounced effects at elevated temperature. Conclusions This study demonstrated the remarkable xylanase-producing ability and strategy of sequential lignocellulose breakdown of M. cinnamomea N12. A new process for the hydrolysis of lignocellulosic biomass was proposed, comprising thermophilic enzymolysis by enzymes of M. cinnamomea N12 followed with mesophilic enzymolysis by commercial cellulases. Developing M. cinnamomea N12 as platforms for thermophilic enzyme mixture production will provide new perspectives for improved conversion yields for current biomass saccharification schemes.
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Gebbie L, Dam TT, Ainscough R, Palfreyman R, Cao L, Harrison M, O'Hara I, Speight R. A snapshot of microbial diversity and function in an undisturbed sugarcane bagasse pile. BMC Biotechnol 2020; 20:12. [PMID: 32111201 PMCID: PMC7049217 DOI: 10.1186/s12896-020-00609-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/24/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Sugarcane bagasse is a major source of lignocellulosic biomass, yet its economic potential is not fully realised. To add value to bagasse, processing is needed to gain access to the embodied recalcitrant biomaterials. When bagasse is stored in piles in the open for long periods it is colonised by microbes originating from the sugarcane, the soil nearby or spores in the environment. For these microorganisms to proliferate they must digest the bagasse to access carbon for growth. The microbial community in bagasse piles is thus a potential resource for the discovery of useful and novel microbes and industrial enzymes. We used culturing and metabarcoding to understand the diversity of microorganisms found in a uniquely undisturbed bagasse storage pile and screened the cultured organisms for fibre-degrading enzymes. RESULTS Samples collected from 60 to 80 cm deep in the bagasse pile showed hemicellulose and partial lignin degradation. One hundred and four microbes were cultured from different layers and included a high proportion of oleaginous yeast and biomass-degrading fungi. Overall, 70, 67, 70 and 57% of the microbes showed carboxy-methyl cellulase, xylanase, laccase and peroxidase activity, respectively. These percentages were higher in microbes selectively cultured from deep layers, with all four activities found for 44% of these organisms. Culturing and amplicon sequencing showed that there was less diversity and therefore more selection in the deeper layers, which were dominated by thermophiles and acid tolerant organisms, compared with the top of pile. Amplicon sequencing indicated that novel fungi were present in the pile. CONCLUSIONS A combination of culture-dependent and independent methods was successful in exploring the diversity in the bagasse pile. The variety of species that was found and that are known for biomass degradation shows that the bagasse pile was a valuable selective environment for the identification of new microbes and enzymes with biotechnological potential. In particular, lignin-modifying activities have not been reported previously for many of the species that were identified, suggesting future studies are warranted.
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Affiliation(s)
- Leigh Gebbie
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia
| | - Tuan Tu Dam
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia
| | - Rebecca Ainscough
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia
| | - Robin Palfreyman
- Metabolomics Australia, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Li Cao
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia
| | - Mark Harrison
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia
| | - Ian O'Hara
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia
| | - Robert Speight
- Queensland University of Technology, 2 George St, Brisbane, QLD, 4000, Australia.
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Velasco J, Oliva B, Mulinari EJ, Quintero LP, da Silva Lima A, Gonçalves AL, Gonçalves TA, Damasio A, Squina FM, Ferreira Milagres AM, Abdella A, Wilkins MR, Segato F. Heterologous expression and functional characterization of a GH10 endoxylanase from Aspergillus fumigatus var. niveus with potential biotechnological application. Biotechnol Rep (Amst) 2019; 24:e00382. [PMID: 31799141 PMCID: PMC6881608 DOI: 10.1016/j.btre.2019.e00382] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 08/26/2019] [Accepted: 09/26/2019] [Indexed: 10/25/2022]
Abstract
Xylanases decrease the xylan content in pretreated biomass releasing it from hemicellulose, thus improving the accessibility of cellulose for cellulases. In this work, an endo-β-1,4-xylanase from Aspergillus fumigatus var. niveus (AFUMN-GH10) was successfully expressed. The structural analysis and biochemical characterization showed this AFUMN-GH10 does not contain a carbohydrate-binding module. The enzyme retained its activity in a pH range from 4.5 to 7.0, with an optimal temperature at 60 °C. AFUMN-GH10 showed the highest activity in beechwood xylan. The mode of action of AFUMN-GH10 was investigated by hydrolysis of APTS-labeled xylohexaose, which resulted in xylotriose and xylobiose as the main products. AFUMN-GH10 released 27% of residual xylan from hydrothermally-pretreated corn stover and 14% of residual xylan from hydrothermally-pretreated sugarcane bagasse. The results showed that environmentally friendly pretreatment followed by enzymatic hydrolysis with AFUMN-GH10 in low concentration is a suitable method to remove part of residual and recalcitrant hemicellulose from biomass.
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Affiliation(s)
- Josman Velasco
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Bianca Oliva
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Evandro José Mulinari
- Department of Physics and Applied Sciences, São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil
| | - Leidy Patricia Quintero
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Awana da Silva Lima
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Aline Larissa Gonçalves
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Thiago Augusto Gonçalves
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
- Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba, Sorocaba, SP, Brazil
| | - André Damasio
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - Fabio Marcio Squina
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
- Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba, Sorocaba, SP, Brazil
| | | | - Asmaa Abdella
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
- Industrial Agricultural Products Center, University of Nebraska-Lincoln, Lincoln, NE, USA
- Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Mark R. Wilkins
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
- Industrial Agricultural Products Center, University of Nebraska-Lincoln, Lincoln, NE, USA
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Fernando Segato
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
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Liew KJ, Ngooi CY, Shamsir MS, Sani RK, Chong CS, Goh KM. Heterologous expression, purification and biochemical characterization of a new endo-1,4-β-xylanase from Rhodothermaceae bacterium RA. Protein Expr Purif 2019; 164:105464. [DOI: 10.1016/j.pep.2019.105464] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/10/2019] [Accepted: 07/31/2019] [Indexed: 11/28/2022]
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Abstract
Abstract
Xylan is the second most abundant naturally occurring renewable polysaccharide available on earth. It is a complex heteropolysaccharide consisting of different monosaccharides such as l-arabinose, d-galactose, d-mannoses and organic acids such as acetic acid, ferulic acid, glucuronic acid interwoven together with help of glycosidic and ester bonds. The breakdown of xylan is restricted due to its heterogeneous nature and it can be overcome by xylanases which are capable of cleaving the heterogeneous β-1,4-glycoside linkage. Xylanases are abundantly present in nature (e.g., molluscs, insects and microorganisms) and several microorganisms such as bacteria, fungi, yeast, and algae are used extensively for its production. Microbial xylanases show varying substrate specificities and biochemical properties which makes it suitable for various applications in industrial and biotechnological sectors. The suitability of xylanases for its application in food and feed, paper and pulp, textile, pharmaceuticals, and lignocellulosic biorefinery has led to an increase in demand of xylanases globally. The present review gives an insight of using microbial xylanases as an “Emerging Green Tool” along with its current status and future prospective.
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Rodríguez-Mendoza J, Santiago-Hernández A, Alvarez-Zúñiga MT, Gutiérrez-Antón M, Aguilar-Osorio G, Hidalgo-Lara ME. Purification and biochemical characterization of a novel thermophilic exo-β-1,3-glucanase from the thermophile biomass-degrading fungus Thielavia terrestris Co3Bag1. ELECTRON J BIOTECHN 2019. [DOI: 10.1016/j.ejbt.2019.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Wang XW, Bai FY, Bensch K, Meijer M, Sun BD, Han YF, Crous PW, Samson RA, Yang FY, Houbraken J. Phylogenetic re-evaluation of Thielavia with the introduction of a new family Podosporaceae. Stud Mycol 2019; 93:155-252. [PMID: 31824584 PMCID: PMC6816082 DOI: 10.1016/j.simyco.2019.08.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genus Thielavia is morphologically defined by having non-ostiolate ascomata with a thin peridium composed of textura epidermoidea, and smooth, single-celled, pigmented ascospores with one germ pore. Thielavia is typified with Th. basicola that grows in close association with a hyphomycete which was traditionally identified as Thielaviopsis basicola. Besides Th. basicola exhibiting the mycoparasitic nature, the majority of the described Thielavia species are from soil, and some have economic and ecological importance. Unfortunately, no living type material of Th. basicola exists, hindering a proper understanding of the classification of Thielavia. Therefore, Thielavia basicola was neotypified by material of a mycoparasite presenting the same ecology and morphology as described in the original description. We subsequently performed a multi-gene phylogenetic analyses (rpb2, tub2, ITS and LSU) to resolve the phylogenetic relationships of the species currently recognised in Thielavia. Our results demonstrate that Thielavia is highly polyphyletic, being related to three family-level lineages in two orders. The redefined genus Thielavia is restricted to its type species, Th. basicola, which belongs to the Ceratostomataceae (Melanosporales) and its host is demonstrated to be Berkeleyomyces rouxiae, one of the two species in the "Thielaviopsis basicola" species complex. The new family Podosporaceae is sister to the Chaetomiaceae in the Sordariales and accommodates the re-defined genera Podospora, Trangularia and Cladorrhinum, with the last genus including two former Thielavia species (Th. hyalocarpa and Th. intermedia). This family also includes the genetic model species Podospora anserina, which was combined in Triangularia (as Triangularia anserina). The remaining Thielavia species fall in ten unrelated clades in the Chaetomiaceae, leading to the proposal of nine new genera (Carteria, Chrysanthotrichum, Condenascus, Hyalosphaerella, Microthielavia, Parathielavia, Pseudothielavia, Stolonocarpus and Thermothielavioides). The genus Canariomyces is transferred from Microascaceae (Microascales) to Chaetomiaceae based on its type species Can. notabilis. Canariomyces is closely related to the human-pathogenic genus Madurella, and includes three thielavia-like species and one novel species. Three monotypic genera with a chaetomium-like morph (Brachychaeta, Chrysocorona and Floropilus) are introduced to better resolve the Chaetomiaceae and the thielavia-like species in the family. Chrysocorona lucknowensis and Brachychaeta variospora are closely related to Acrophialophora and three newly introduced genera containing thielavia-like species; Floropilus chiversii is closely related to the industrially important and thermophilic species Thermothielavioides terrestris (syn. Th. terrestris). This study shows that the thielavia-like morph is a homoplastic form that originates from several separate evolutionary events. Furthermore, our results provide new insights into the taxonomy of Sordariales and the polyphyletic Lasiosphaeriaceae.
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Affiliation(s)
- X W Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No. 3, 1st Beichen West Road, Chaoyang District, Beijing, 100101, China.,Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - F Y Bai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No. 3, 1st Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - K Bensch
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - M Meijer
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - B D Sun
- China General Microbiological Culture Collection Centre, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Y F Han
- Institute of Fungus Resources, Guizhou University, Guiyang, Guizhou, 550025, China
| | - P W Crous
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands.,Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa.,Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - R A Samson
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - F Y Yang
- Grassland Institute, College of Animal Science & Technology, China Agricultural University, NO. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100093, China
| | - J Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
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Meng Z, Yang Q, Wang J, Hou Y. Cloning, Characterization, and Functional Expression of a Thermostable Type B Feruloyl Esterase from Thermophilic Thielavia Terrestris. Appl Biochem Biotechnol 2019; 189:1304-17. [DOI: 10.1007/s12010-019-03065-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 06/07/2019] [Indexed: 10/26/2022]
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17
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Chadha BS, Kaur B, Basotra N, Tsang A, Pandey A. Thermostable xylanases from thermophilic fungi and bacteria: Current perspective. Bioresour Technol 2019; 277:195-203. [PMID: 30679061 DOI: 10.1016/j.biortech.2019.01.044] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/06/2019] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Thermostable xylanases from thermophilic fungi and bacteria have a wide commercial acceptability in feed, food, paper and pulp and bioconversion of lignocellulosics with an estimated annual market of USD 500 Million. The genome wide analysis of thermophilic fungi clearly shows the presence of elaborate genetic information coding for multiple xylanases primarily coding for GH10, GH11 in addition to GH7 and GH30 xylanases. The transcriptomics and proteome profiling has given insight into the differential expression of these xylanases in some of the thermophilic fungi. Bioprospecting has resulted in identification of novel thermophilic xylanases that have been endorsed by the industrial houses for heterologous over- expression and formulations. The future use of xylanases is expected to increase exponentially for their role in biorefineries. The discovery of new and improvement of existing xylanases using molecular tools such as directed evolution is expected to be the mainstay to meet increasing demand of thermostable xylanases.
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Affiliation(s)
- B S Chadha
- Department of Microbiology, Guru Nanak Dev University, Amritsar 143 005, India.
| | - Baljit Kaur
- Department of Microbiology, Guru Nanak Dev University, Amritsar 143 005, India
| | - Neha Basotra
- Department of Microbiology, Guru Nanak Dev University, Amritsar 143 005, India
| | - Adrian Tsang
- Center for Structural and Functional Genomics, Concordia University, Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow 226 001, India.
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Tang J, Long L, Cao Y, Ding S. Expression and characterization of two glucuronoyl esterases from Thielavia terrestris and their application in enzymatic hydrolysis of corn bran. Appl Microbiol Biotechnol 2019; 103:3037-3048. [DOI: 10.1007/s00253-019-09662-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/08/2019] [Accepted: 01/22/2019] [Indexed: 01/13/2023]
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Dlangamandla N, Ntwampe S, Angadam J, Itoba-tombo E, Chidi B, Mekuto L. Integrated Hydrolysis of Mixed Agro-Waste for a Second Generation Biorefinery Using Nepenthes mirabilis Pod Digestive Fluids. Processes (Basel) 2019; 7:64. [DOI: 10.3390/pr7020064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To sustainably operate a biorefinery with a low cost input in a commercial setting, the hydrolysis of lignocellulosic biomass must be undertaken in a manner which will impart environmental tolerance while reducing fermenter inhibitors from the delignification process. The challenge lies with the highly recalcitrant lignin structure, which limits the conversion of the holocelluloses to fermentable total reducing sugars (TRS). Due to these challenges, sustainable and innovative methods to pre-treat biomass must be developed for delignocellulolytic operations. Herein, Nepenthes mirabilis digestive fluids shown to have ligninolytic, cellulolytic and xylanolytic activities were used as an enzyme cocktail to hydrolyse mixed agro-waste constituted by Citrus sinensis (orange), Malus domestica (apple) peels, cobs from Zea mays (maize) and Quercus robur (oak) yard waste. The digestive fluids contained carboxylesterases (529.41 ± 30.50 U/L), β-glucosidases (251.94 ± 11.48 U/L) and xylanases (36.09 ± 18.04 U/L), constituting an enzymatic cocktail with significant potential for the reduction in total residual phenolic compounds (TRPCs), while being appropriate for holocellulose hydrolysis. Furthermore, the maximum TRS obtainable was 310 ± 5.19 mg/L within 168 h, while the TRPCs were reduced from 6.25 ± 0.18 to 4.26 ± 0.09 mg/L, which was lower than that observed when conventional methods were used. Overall, N. mirabilis digestive fluids demonstrated an ability to support biocatalytic processes with minimised cellulases hydrolysis interference. Therefore, the digestive enzymes in N. mirabilis pods can be used in an integrated system for feedstock hydrolysis in a second generation biorefinery.
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Alvarez-Zúñiga MT, Santiago-Hernández A, Rodríguez-Mendoza J, Campos JE, Pavón-Orozco P, Trejo-Estrada S, Hidalgo-Lara ME. Taxonomic identification of the thermotolerant and fast-growing fungus Lichtheimia ramosa H71D and biochemical characterization of the thermophilic xylanase LrXynA. AMB Express 2017; 7:194. [PMID: 29098440 DOI: 10.1186/s13568-017-0494-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 10/26/2017] [Indexed: 11/12/2022] Open
Abstract
The zygomycete fungus Lichtheimia ramosa H71D, isolated from sugarcane bagasse compost, was identified by applying phylogenetic analysis based on the DNA sequence of the Internal Transcribed Spacer (ITS), and subsequent secondary structure analysis of ITS2. L. ramosa H71D was able to grow over a wide range of temperatures (25–45 °C), manifesting optimal growth at 37 °C. A 64 kDa xylanase (named LrXynA) was purified from the culture supernatant of L. ramosa H71D grown on 2% carboxymethylcellulose (CMC), as the only carbon source. LrXynA displayed optimal activity at pH 6 and temperature of 65 °C. The enzyme retained more than 50% of its maximal activity over a broad range of pH values (4.5–7.5). Enzyme half-life (t½) times at 55, 65 and 75 °C were 80, 25, and 8 min, respectively. LrXynA showed higher affinity (kM of 2.87 mg/mL) and catalytic efficiency (kcat/kM of 0.651 mg s/mL) towards Beechwood xylan in comparison to other substrates such as Birchwood xylan, Oat-spelt xylan, CMC, Avicel and Solka floc. The predominant final products from LrXynA-mediated hydrolysis of Beechwood xylan were xylobiose and xylotriose, suggesting that the enzyme is an endo-β-1,4 xylanase. Scanning electron microscopy (SEM) imaging of sugar cane bagasse (SCB) treated with LrXynA, alone or in combination with commercial cellulases, showed a positive effect on the hydrolysis of SCB. To our knowledge, this is the first report focusing on the biochemical and functional characterization of an endo-β-1,4 xylanase from the thermotolerant and fast-growing fungus Lichtheimia ramosa.
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Harris KL, Thomson RES, Strohmaier SJ, Gumulya Y, Gillam EMJ. Determinants of thermostability in the cytochrome P450 fold. Biochim Biophys Acta Proteins Proteom 2017; 1866:97-115. [PMID: 28822812 DOI: 10.1016/j.bbapap.2017.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/19/2017] [Accepted: 08/07/2017] [Indexed: 10/19/2022]
Abstract
Cytochromes P450 are found throughout the biosphere in a wide range of environments, serving a multitude of physiological functions. The ubiquity of the P450 fold suggests that it has been co-opted by evolution many times, and likely presents a useful compromise between structural stability and conformational flexibility. The diversity of substrates metabolized and reactions catalyzed by P450s makes them attractive starting materials for use as biocatalysts of commercially useful reactions. However, process conditions impose different requirements on enzymes to those in which they have evolved naturally. Most natural environments are relatively mild, and therefore most P450s have not been selected in Nature for the ability to withstand temperatures above ~40°C, yet industrial processes frequently require extended incubations at much higher temperatures. Thus, there has been considerable interest and effort invested in finding or engineering thermostable P450 systems. Numerous P450s have now been identified in thermophilic organisms and analysis of their structures provides information as to mechanisms by which the P450 fold can be stabilized. In addition, protein engineering, particularly by directed or artificial evolution, has revealed mutations that serve to stabilize particular mesophilic enzymes of interest. Here we review the current understanding of thermostability as it applies to the P450 fold, gleaned from the analysis of P450s characterized from thermophilic organisms and the parallel engineering of mesophilic forms for greater thermostability. We then present a perspective on how this information might be used to design stable P450 enzymes for industrial application. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
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Affiliation(s)
- Kurt L Harris
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Raine E S Thomson
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Silja J Strohmaier
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Yosephine Gumulya
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia
| | - Elizabeth M J Gillam
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia 4072, Australia.
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