Characterization of a halotolerant GH2 family β-galactosidase GalM from Microvirga sp. strain MC18

Xiaowen Wang; Sibo Chen; Lin Fan; Hao Liu; Si Chen; Xianfeng Ye; Zhoukun Li; Zhongli Cui; Yan Huang

doi:10.1016/j.pep.2022.106074

Characterization of a halotolerant GH2 family β-galactosidase GalM from Microvirga sp. strain MC18

Protein Expr Purif. 2022 Jun:194:106074. doi: 10.1016/j.pep.2022.106074. Epub 2022 Feb 23.

Authors

Xiaowen Wang¹, Sibo Chen¹, Lin Fan¹, Hao Liu¹, Si Chen¹, Xianfeng Ye¹, Zhoukun Li¹, Zhongli Cui¹, Yan Huang²

Affiliations

¹ Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
² Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China. Electronic address: huangyan@njau.edu.cn.

PMID: 35218889
DOI: 10.1016/j.pep.2022.106074

Abstract

A new glycoside hydrolase family 2 (GH2) β-galactosidase encoding gene galM was cloned from Microvirga sp. strain MC18 and overexpressed in Escherichia coli. The recombinant β-galactosidase GalM showed optimal activity at pH 7.0 and 50 °C, with a stability at pH 6.0-9.0 and 20-40 °C, which are conditions suitable for the diary environment. The K_m and V_max values for o-nitrophenyl-β-d-galactopyranoside (oNPG) were 1.30 mmol/L and 15.974 μmol/(min·mg), respectively. GalM showed low product inhibition by galactose with a K_i of 73.18 mM and high tolerance for glucose that 86.5% activity retained in the presence of 500 mM glucose. It was also stable and active in 20% of methanol, ethanol and isopropanol. In addition, the enzyme activity of GalM was activated significantly over 0-2 mol/L NaCl (1.6-4.3 fold). These favorable properties make GalM a potential candidate for the industrial application.

Keywords: Glycoside hydrolase family 2; Halotolerant; Microvirga sp. strain MC18; β-Galactosidase.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Escherichia coli* / genetics
Escherichia coli* / metabolism
Galactose*
Glucose
Hydrogen-Ion Concentration
Kinetics
Methylobacteriaceae / enzymology*
beta-Galactosidase / metabolism

Substances

beta-Galactosidase
Glucose
Galactose