Biochemical characterization of a xylose-tolerant GH43 β-xylosidase from Geobacillus thermodenitrificans.

Autor: Melo VS; Laboratory of Biochemistry and Protein Biotechnology, School of Arts, Sciences and Humanities, University of São Paulo, Av. Arlindo Bettio, 1000, São Paulo, CEP: 03828000, Brazil., Gomes BM; Laboratory of Biochemistry and Protein Biotechnology, School of Arts, Sciences and Humanities, University of São Paulo, Av. Arlindo Bettio, 1000, São Paulo, CEP: 03828000, Brazil., Chambergo FS; Laboratory of Biochemistry and Protein Biotechnology, School of Arts, Sciences and Humanities, University of São Paulo, Av. Arlindo Bettio, 1000, São Paulo, CEP: 03828000, Brazil. Electronic address: fscha@usp.br.
Jazyk: angličtina
Zdroj: Carbohydrate research [Carbohydr Res] 2023 Oct; Vol. 532, pp. 108901. Date of Electronic Publication: 2023 Jul 20.
DOI: 10.1016/j.carres.2023.108901
Abstrakt: Hemicelluloses are the second most abundant polysaccharide in plant biomass, in which xylan is the main constituent. Aiming at the total degradation of xylan and the obtention of fermentable sugars, several enzymes acting synergistically are required, especially β-xylosidases. In this study, β-xylosidase from Geobacillus thermodenitrificans (GtXyl) was expressed in E. coli BL21 and characterized. The enzyme GtXyl has been grouped within the family of glycoside hydrolases 43 (GH43). Results showed that GtXyl obtained the highest activity at pH 5.0 and temperature of 60 °C. In the additive's tests, the enzyme remained stable in the presence of metal ions and EDTA, and showed high tolerance to xylose, with a relative activity of 55.4% at 400 mM. The enzyme also presented bifunctional activity of β-xylosidase and α-l-arabinofuranosidase, with the highest activity on the substrate p-nitrophenyl-β-d-xylopyranoside. The specific activity on p-nitrophenyl-β-d-xylopyranoside was 18.33 U mg -1 and catalytic efficiency of 20.21 mM -1  s -1 , which is comparable to other β-xylosidases reported in the literature. Putting together, the GtXyl enzyme presented interesting biochemical characteristics that are desirable for the application in the enzymatic hydrolysis of plant biomass, such as activity at higher temperatures, high thermostability and stability to metal ions.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
(Copyright © 2023 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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