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Characterization of a furan aldehyde‐tolerant β ‐xylosidase/ α ‐arabinosidase obtained through a synthetic metagenomics approach
Author(s) -
Maruthamuthu M.,
Jiménez D.J.,
Elsas J.D.
Publication year - 2017
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13484
Subject(s) - xylose , biochemistry , escherichia coli , enzyme , chemistry , metagenomics , pichia pastoris , hydrolysis , recombinant dna , biology , fermentation , gene
Aims The aim of the study was to characterize 10 hemicellulolytic enzymes obtained from a wheat straw‐degrading microbial consortium. Methods and Results Based on previous metagenomics analyses, 10 glycosyl hydrolases were selected, codon‐optimized, synthetized, cloned and expressed in Escherichia coli . Nine of the overexpressed recombinant proteins accumulated in cellular inclusion bodies, whereas one, a 37·5‐ kD a protein encoded by gene xyl M1989, was found in the soluble fractions. The resulting protein, denoted XylM1989, showed β ‐xylosidase and α ‐arabinosidase activities. It fell in the GH 43 family and resembled a Sphingobacterium sp. protein. The XylM1989 showed optimum activity at 20°C and pH 8·0. Interestingly, it kept approximately 80% of its β ‐xylosidase activity in the presence of 0·5% (w/v) furfural and 0·1% (w/v) 5‐hydroxymethylfurfural. Additionally, the presence of Ca 2+ , Mg 2+ and Mn 2+ ions increased the enzymatic activity and conferred complete tolerance to 500 mmol l −1 of xylose. Protein XylM1989 is also able to release sugars from complex polysaccharides. Conclusion We report the characterization of a novel bifunctional hemicellulolytic enzyme obtained through a targeted synthetic metagenomics approach. Significance and Impact of the Study The properties of XylM1989 turn this protein into a promising enzyme that could be useful for the efficient saccharification of plant biomass.