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Elucidating Sequence and Structural Determinants of Carbohydrate Esterases for Complete Deacetylation of Substituted Xylans. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092655. [PMID: 35566004 PMCID: PMC9105624 DOI: 10.3390/molecules27092655] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/07/2022] [Accepted: 04/14/2022] [Indexed: 11/26/2022]
Abstract
Acetylated glucuronoxylan is one of the most common types of hemicellulose in nature. The structure is formed by a β-(1→4)-linked D-xylopyranosyl (Xylp) backbone that can be substituted with an acetyl group at O-2 and O-3 positions, and α-(1→2)-linked 4-O-methylglucopyranosyluronic acid (MeGlcpA). Acetyl xylan esterases (AcXE) that target mono- or doubly acetylated Xylp are well characterized; however, the previously studied AcXE from Flavobacterium johnsoniae (FjoAcXE) was the first to remove the acetyl group from 2-O-MeGlcpA-3-O-acetyl-substituted Xylp units, yet structural characteristics of these enzymes remain unspecified. Here, six homologs of FjoAcXE were produced and three crystal structures of the enzymes were solved. Two of them are complex structures, one with bound MeGlcpA and another with acetate. All homologs were confirmed to release acetate from 2-O-MeGlcpA-3-O-acetyl-substituted xylan, and the crystal structures point to key structural elements that might serve as defining features of this unclassified carbohydrate esterase family. Enzymes comprised two domains: N-terminal CBM domain and a C-terminal SGNH domain. In FjoAcXE and all studied homologs, the sequence motif around the catalytic serine is Gly-Asn-Ser-Ile (GNSI), which differs from other SGNH hydrolases. Binding by the MeGlcpA-Xylp ligand is directed by positively charged and highly conserved residues at the interface of the CBM and SGNH domains of the enzyme.
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2
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Li X, Dilokpimol A, Kabel MA, de Vries RP. Fungal xylanolytic enzymes: Diversity and applications. BIORESOURCE TECHNOLOGY 2022; 344:126290. [PMID: 34748977 DOI: 10.1016/j.biortech.2021.126290] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 05/26/2023]
Abstract
As important polysaccharide degraders in nature, fungi can diversify their extensive set of carbohydrate-active enzymes to survive in ecological habitats of various composition. Among these enzymes, xylanolytic ones can efficiently and sustainably degrade xylans into (fermentable) monosaccharides to produce valuable chemicals or fuels from, for example relevant for upgrading agro-food industrial side streams. Moreover, xylanolytic enzymes are being used in various industrial applications beyond biomass saccharification, e.g. food, animal feed, biofuel, pulp and paper. As a reference for researchers working in related areas, this review summarized the current knowledge on substrate specificity of xylanolytic enzymes from different families of the Carbohydrate-Active enZyme database. Additionally, the diversity of enzyme sets in fungi were discussed by comparing the number of genes encoding xylanolytic enzymes in selected fungal genomes. Finally, to support bio-economy, the current applications of fungal xylanolytic enzymes in industry were reviewed.
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Affiliation(s)
- Xinxin Li
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Adiphol Dilokpimol
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Mirjam A Kabel
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
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3
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Glycoside Hydrolase family 30 harbors fungal subfamilies with distinct polysaccharide specificities. N Biotechnol 2021; 67:32-41. [PMID: 34952234 DOI: 10.1016/j.nbt.2021.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/19/2021] [Accepted: 12/19/2021] [Indexed: 11/21/2022]
Abstract
Efficient bioconversion of agro-industrial side streams requires a wide range of enzyme activities. Glycoside Hydrolase family 30 (GH30) is a diverse family that contains various catalytic functions and has so far been divided into ten subfamilies (GH30_1-10). In this study, a GH30 phylogenetic tree using over 150 amino acid sequences was contructed. The members of GH30 cluster into four subfamilies and eleven candidates from these subfamilies were selected for biochemical characterization. Novel enzyme activities were identified in GH30. GH30_3 enzymes possess β-(1→6)-glucanase activity. GH30_5 targets β-(1→6)-galactan with mainly β-(1→6)-galactobiohydrolase catalytic behavior. β-(1→4)-Xylanolytic enzymes belong to GH30_7 targeting β-(1→4)-xylan with several activities (e.g. xylobiohydrolase, endoxylanase). Additionally, a new fungal subfamily in GH30 was proposed, i.e. GH30_11, which displays β-(1→6)-galactobiohydrolase. This study confirmed that GH30 fungal subfamilies harbor distinct polysaccharide specificity and have high potential for the production of short (non-digestible) di- and oligosaccharides.
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4
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Molecular modification, structural characterization, and biological activity of xylans. Carbohydr Polym 2021; 269:118248. [PMID: 34294285 DOI: 10.1016/j.carbpol.2021.118248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 12/17/2022]
Abstract
The differences in the source and structure of xylans make them have various biological activities. However, due to their inherent structural limitations, the various biological activities of xylans are far lower than those of commercial drugs. Currently, several types of molecular modification methods have been developed to address these limitations, and many derivatives with specific biological activity have been obtained. Further research on structural characteristics, structure-activity relationship and mechanism of action is of great significance for the development of xylan derivatives. Therefore, the major molecular modification methods of xylans are introduced in this paper, and the primary structure and conformation characteristics of xylans and their derivatives are summarized. In addition, the biological activity and structure-activity relationship of the modified xylans are also discussed.
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Raji O, Arnling Bååth J, Vuong TV, Larsbrink J, Olsson L, Master ER. The coordinated action of glucuronoyl esterase and α-glucuronidase promotes the disassembly of lignin-carbohydrate complexes. FEBS Lett 2021; 595:351-359. [PMID: 33277689 PMCID: PMC8044923 DOI: 10.1002/1873-3468.14019] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/19/2022]
Abstract
Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by the presence of lignin–carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated action of a glucuronoyl esterase (TtCE15A) and two α‐glucuronidases (SdeAgu115A and AxyAgu115A). When supplementing α‐glucuronidase with equimolar quantities of TtCE15A, total MeGlcpA released after 72 h by SdeAgu115A and AxyAgu115A increased from 52% to 67%, and 61% to 95%, respectively. Based on the combined TtCE15A and AxyAgu115A activities, ~ 34% of MeGlcpA in the extracted birchwood glucuronoxylan was occupied as LCCs. Notably, insoluble LCC fractions reduced soluble α‐glucuronidase concentrations by up to 70%, whereas reduction in soluble TtCE15A was less than 30%, indicating different tendencies to adsorb onto the LCC substrate.
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Affiliation(s)
- Olanrewaju Raji
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada
| | - Jenny Arnling Bååth
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Thu V Vuong
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada
| | - Johan Larsbrink
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Lisbeth Olsson
- Department of Biology and Biological Engineering, Wallenberg Wood Science Center, Chalmers University of Technology, Gothenburg, Sweden
| | - Emma R Master
- Department of Chemical Engineering and Applied Science, University of Toronto, ON, Canada.,Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland
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Rade LL, da Silva MNP, Vieira PS, Milan N, de Souza CM, de Melo RR, Klein BC, Bonomi A, de Castro HF, Murakami MT, Zanphorlin LM. A Novel Fungal Lipase With Methanol Tolerance and Preference for Macaw Palm Oil. Front Bioeng Biotechnol 2020; 8:304. [PMID: 32435636 PMCID: PMC7218172 DOI: 10.3389/fbioe.2020.00304] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/20/2020] [Indexed: 11/18/2022] Open
Abstract
Macaw palm is a highly oil-producing plant, which presents high contents of free fatty acids, being a promising feedstock for biofuel production. The current chemical routes are costly and complex, involving highly harsh industrial conditions. Enzymatic processing is a potential alternative; however, it is hampered by the scarce knowledge on biocatalysts adapted to this acidic feedstock. This work describes a novel lipase isolated from the thermophilic fungus Rasamsonia emersonii (ReLip), which tolerates extreme conditions such as the presence of methanol, high temperatures, and acidic medium. Among the tested feedstocks, the enzyme showed the highest preference for macaw palm oil, producing a hydrolyzate with a final free fatty acid content of 92%. Crystallographic studies revealed a closed conformation of the helical amphipathic lid that typically undergoes conformational changes in a mechanism of interfacial activation. Such conformation of the lid is stabilized by a salt bridge, not observed in other structurally characterized homologs, which is likely involved in the tolerance to organic solvents. Moreover, the lack of conservation of the aromatic cluster IxxWxxxxxF in the lid of ReLip with the natural mutation of the phenylalanine by an alanine might be correlated with the preference of short acyl chains, although preserving catalytic activity on insoluble substrates. In addition, the presence of five acidic amino acids in the lid of ReLip, a rare property reported in other lipases, may have contributed to its ability to tolerate and be effective in acidic environments. Therefore, our work describes a new fungal biocatalyst capable of efficiently hydrolyzing macaw oil, an attractive feedstock for the production of "drop-in" biofuels, with high desirable feature for industrial conditions such as thermal and methanol tolerance, and optimum acidic pH. Moreover, the crystallographic structure was elucidated, providing a structural basis for the enzyme substrate preference and tolerance to organic solvents.
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Affiliation(s)
- Letícia L. Rade
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Melque N. P. da Silva
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Plínio S. Vieira
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Natalia Milan
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
- Department of Chemical Engineering, Engineering School of Lorena, University of São Paulo, Lorena, Brazil
| | - Claudia M. de Souza
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Ricardo R. de Melo
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Bruno C. Klein
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Antonio Bonomi
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Heizir F. de Castro
- Department of Chemical Engineering, Engineering School of Lorena, University of São Paulo, Lorena, Brazil
| | - Mário T. Murakami
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Leticia M. Zanphorlin
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
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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] [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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Bhardwaj N, Kumar B, Verma P. A detailed overview of xylanases: an emerging biomolecule for current and future prospective. BIORESOUR BIOPROCESS 2019. [DOI: 10.1186/s40643-019-0276-2] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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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9
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Shimekake Y, Furuichi T, Abe K, Kera Y, Takahashi S. A novel thermostable D-amino acid oxidase of the thermophilic fungus Rasamsonia emersonii strain YA. Sci Rep 2019; 9:11948. [PMID: 31420577 PMCID: PMC6697736 DOI: 10.1038/s41598-019-48480-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/06/2019] [Indexed: 11/16/2022] Open
Abstract
d-Amino acid oxidase (DAAO) is a valuable flavoenzyme capable of being used in various practical applications, such as in determining d-amino acids and producing a material for semisynthetic cephalosporins, requiring higher thermal stability, higher catalytic activity, and broad substrate specificity. In this study, we isolated the thermophilic fungus Rasamsonia emersonii strain YA, which can grow on several d-amino acids as the sole nitrogen source, from a compost and characterized DAAO (ReDAAO) of the fungus. ReDAAO expressed in Escherichia coli exhibited significant oxidase activity against various neutral and basic d-amino acids, in particular hydrophobic d-amino acids. In addition, the enzyme also significantly acted on cephalosporin C, a starting material for semisynthetic antibiotics, and d-Glu, a general substrate for d-aspartate oxidase but not for DAAO, showing its unique and practically useful substrate specificity. The apparent kcat and Km values of the enzyme toward good substrates were comparable to those of higher catalytic fungal DAAOs, and the thermal stability (T50 value of ~60 °C) was comparable to that of a thermophilic bacterial DAAO and significantly higher than that of other eukaryotic DAAOs. These results highlight the great potential of ReDAAO for use in practical applications.
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Affiliation(s)
- Yuya Shimekake
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Takehiro Furuichi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Katsumasa Abe
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Yoshio Kera
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Shouji Takahashi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
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Yi Z, Jin Y, Xiao Y, Chen L, Tan L, Du A, He K, Liu D, Luo H, Fang Y, Zhao H. Unraveling the Contribution of High Temperature Stage to Jiang-Flavor Daqu, a Liquor Starter for Production of Chinese Jiang-Flavor Baijiu, With Special Reference to Metatranscriptomics. Front Microbiol 2019; 10:472. [PMID: 30930875 PMCID: PMC6423406 DOI: 10.3389/fmicb.2019.00472] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/22/2019] [Indexed: 12/27/2022] Open
Abstract
Jiang-flavor (JF) daqu is a liquor starter used for production of JF baijiu, a well-known distilled liquor in China. Although a high temperature stage (70°C) is necessary for qualifying JF daqu, little is known regarding its active microbial community and functional enzymes, along with its role in generating flavor precursors for JF baijiu aroma. In this investigation, based on metatranscriptomics, fungi, such as Aspergillus and Penicillium, were identified as the most active microbial members and 230 carbohydrate-active enzymes were identified as potential saccharifying enzymes at 70°C of JF daqu. Notably, most of enzymes in identified carbohydrate and energy pathways showed lower expression levels at 70°C of JF daqu than those at the high temperature stage (62°C) of Nong-flavor (NF) daqu, indicating lowering capacities of saccharification and fermentation by high temperature stage. Moreover, many enzymes, especially those related to the degradation of aromatic compounds, were only detected with low expression levels at 70°C of JF daqu albeit not at 62°C of NF daqu, indicating enhancing capacities of generating special trace aroma compounds in JF daqu by high temperature stage. Additionally, most of enzymes related to those capacities were highly expressed at 70°C by fungal genus of Aspergillus, Coccidioides, Paracoccidioides, Penicillium, and Rasamsonia. Therefore, this study not only sheds light on the crucial functions of high temperature stage but also paves the way to improve the quality of JF baijiu and provide active community and functional enzymes for other fermentation industries.
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Affiliation(s)
- Zhuolin Yi
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, China
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Yanling Jin
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Yao Xiao
- Analytical and Testing Center, Sichuan University of Science and Engineering, Zigong, China
| | - Lanchai Chen
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Li Tan
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Anping Du
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Kaize He
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Dayu Liu
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, China
| | - Huibo Luo
- Bioengineering College, Sichuan University of Science and Engineering, Zigong, China
| | - Yang Fang
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Hai Zhao
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, China
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu, China
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11
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Vos AM, Jurak E, de Gijsel P, Ohm RA, Henrissat B, Lugones LG, Kabel MA, Wösten HAB. Production of α-1,3-L-arabinofuranosidase active on substituted xylan does not improve compost degradation by Agaricus bisporus. PLoS One 2018; 13:e0201090. [PMID: 30040824 PMCID: PMC6057652 DOI: 10.1371/journal.pone.0201090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 07/09/2018] [Indexed: 12/02/2022] Open
Abstract
Agaricus bisporus consumes carbohydrates contained in wheat straw based compost used for commercial mushroom production. Double substituted arabinoxylan is part of the ~40% of the compost polysaccharides that are not degraded by A. bisporus during its growth and development. Genes encoding α-1,3-l-arabinofuranosidase (AXHd3) enzymes that act on xylosyl residues doubly substituted with arabinosyl residues are absent in this mushroom forming fungus. Here, the AXHd3 encoding hgh43 gene of Humicola insolens was expressed in A. bisporus with the aim to improve its substrate utilization and mushroom yield. Transformants secreted active AXHd3 in compost as shown by the degradation of double substituted arabinoxylan oligomers in an in vitro assay. However, carbohydrate composition and degree of arabinosyl substitution of arabinoxylans were not affected in compost possibly due to inaccessibility of the doubly substituted xylosyl residues.
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Affiliation(s)
- Aurin M. Vos
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Edita Jurak
- Laboratory of Food Chemistry, Wageningen University and Research, Wageningen, The Netherlands
| | - Peter de Gijsel
- Laboratory of Food Chemistry, Wageningen University and Research, Wageningen, The Netherlands
| | - Robin A. Ohm
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France
| | - Luis G. Lugones
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Mirjam A. Kabel
- Laboratory of Food Chemistry, Wageningen University and Research, Wageningen, The Netherlands
| | - Han A. B. Wösten
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
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12
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Jonathan MC, DeMartini J, Van Stigt Thans S, Hommes R, Kabel MA. Characterisation of non-degraded oligosaccharides in enzymatically hydrolysed and fermented, dilute ammonia-pretreated corn stover for ethanol production. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:112. [PMID: 28469707 PMCID: PMC5414315 DOI: 10.1186/s13068-017-0803-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 04/23/2017] [Indexed: 05/26/2023]
Abstract
BACKGROUND Corn stover is lignocellulosic biomass that has potential to be used as raw material for bioethanol production. In the current research, dilute ammonia pretreatment was used to improve the accessibility of corn stover carbohydrates to subsequently added hydrolytic enzymes. Some carbohydrates, however, were still present after enzymatic hydrolysis and fermentation. Hence, this research was aimed to characterise the recalcitrant carbohydrates, especially the oligosaccharides that remained after hydrolysis and fermentation of dilute ammonia-pretreated corn stover (DACS). RESULTS About 35% (w/w) of DACS carbohydrates remained after enzymatic hydrolysis and fermentation of the released monosaccharides. One-third of these recalcitrant carbohydrates were water soluble and composed of diverse oligosaccharides. By using UHPLC-MS n , more than 50 oligosaccharides were detected. Glucurono-xylooligosaccharides (UAXOS) with a degree of polymerisation (DP) less than 5 were the most abundant oligosaccharides. The (4-O-methyl) glucuronosyl substituent was mostly attached onto the terminal xylosyl residue. It was shown that the glucuronosyl substituent in some UAXOS was modified into a hexenuronosyl, a glucuronamide or a hexenuronamide residue due to the dilute ammonia pretreatment. Another group of abundant oligosaccharides comprised various xyloglucan oligosaccharides (XGOS), with a DP 5 annotated as XXG as the most pronounced. In addition, disaccharides annotated as xylosyl-glucose with different β linkages as well as larger carbohydrates were present in the fermentation slurry. CONCLUSIONS Around one-third of the 35% (w/w) recalcitrant DACS carbohydrates remained as water-soluble saccharides. In this study, more than 50 recalcitrant oligosaccharides were detected, which mostly composed of xylosyl and/or glucosyl residues. The most pronounced oligosaccharides were UAXOS and XGOS. Hence, α-glucuronidase and α-xylosidase were suggested to be added to the enzyme mixture to degrade these oligosaccharides further, and hence the fermentation yield is potentially increased.
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Affiliation(s)
- M. C. Jonathan
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - J. DeMartini
- DuPont Industrial Biosciences (Genencor Division), 925 Page Mill Road, Palo Alto, CA 94304 USA
| | - S. Van Stigt Thans
- DuPont Industrial Biosciences (Genencor International B.V.), Archimedesweg 30, 2333 CN Leiden, The Netherlands
| | - R. Hommes
- DuPont Industrial Biosciences (Genencor International B.V.), Archimedesweg 30, 2333 CN Leiden, The Netherlands
| | - M. A. Kabel
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
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