Maruthamuthu M, Jiménez DJ, van Elsas JD. Characterization of a furan aldehyde-tolerant β-xylosidase/α-arabinosidase obtained through a synthetic metagenomics approach.
J Appl Microbiol 2017;
123:145-158. [PMID:
28489302 DOI:
10.1111/jam.13484]
[Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/26/2017] [Accepted: 05/03/2017] [Indexed: 12/16/2022]
Abstract
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-kDa protein encoded by gene xylM1989, was found in the soluble fractions. The resulting protein, denoted XylM1989, showed β-xylosidase and α-arabinosidase activities. It fell in the GH43 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 Ca2+ , Mg2+ and Mn2+ 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.
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