Improve ethanol tolerance of β-glucosidase Bgl1A by semi-rational engineering for the hydrolysis of soybean isoflavone glycosides.

Autor: Fang W; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China; Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui 230601, China., Yang Y; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China., Zhang X; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China; Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui 230601, China., Yin Q; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China; Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui 230601, China., Zhang X; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China; Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui 230601, China., Wang X; Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States., Fang Z; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China; Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui 230601, China. Electronic address: zemin_fang@163.com., Yazhong X; School of Life Sciences, Anhui University, Hefei, Anhui 230601, China; Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui 230601, China. Electronic address: yzxiao@ahu.edu.cn.
Jazyk: angličtina
Zdroj: Journal of biotechnology [J Biotechnol] 2016 Jun 10; Vol. 227, pp. 64-71. Date of Electronic Publication: 2016 Apr 12.
DOI: 10.1016/j.jbiotec.2016.04.022
Abstrakt: A β-glucosidase Bgl1A variant (A24S/F297Y) with improved ethanol tolerance was obtained by semi-rational engineering. At 30-40°C, IC50 values (the amount required for inhibiting 50% enzyme activity) of the variant for ethanol were 17-30% (v/v), 1.4- to 2.4-fold of Bgl1A. When incubating in 15% (v/v) ethanol at 30°C, the half-life of A24S/F297Y was 13min; whereas Bgl1A lost all enzyme activity within 5min. A24S/F297Y was more stable at pH 7.5 than at pH 6.5, and more than 50% of the original activity remained after incubation at 30°C for 10h. At 35°C and pH 7.5, the half-life of A24S/F297Y was 80min, 4.3 times longer than that of Bgl1A. When converting isoflavone glycosides to aglycones using A24S/F297Y as catalyst, the hydrolysis rates were 99% for daidzin and 98% for genistin. The concentrations of daidzein and genistein rapidly increased by 7.02mM and 4.35mM within 10min, respectively. These results showed that A24S/F297Y was a promising candidate for the enzymatic hydrolysis of soybean isoflavone glycosides.
(Copyright © 2016 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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