Expression and characterization of a novel trehalase from Microvirga sp. strain MC18

Trehalase catalyzes the hydrolysis of trehalose into two glucose molecules and is present in nearly all tissues in various forms. In this study, a putative bacterial trehalase gene, encoding a glycoside hydrolase family 15 (GH15) protein was identified in Microvirga sp. strain MC18 and heterologously expressed in E. coli. The specific activity of the purified recombinant trehalase MtreH was 24 U/mg, with Km and Vmax values of 23.45 mg/mL and 184.23 μmol/mg/min, respectively. The enzyme exhibited optimal activity at 40 °C and pH 7.0, whereby Ca2+ had a considerable positive effects on the catalytic activity and thermostability. The optimized enzymatic reaction conditions for the bioconversion of trehalose using rMtreH were determined as 40 °C, pH 7.0, 10 h and 1% trehalose concentration. The characterization of this bacterial trehalase improves our understanding of the metabolism and biological role of trehalose in prokaryotic organism.