Purification and some properties of α-amylase from Bacillus subtilis X-23 that glucosylates phenolic compounds such as hydroquinone

Abstract

Six hundred strains of soil microorganisms were screened for the production of hydroquinone glucosylating enzyme (HGE). One of these strains, Bacillus subtilis strain X-23, produced an enzyme that glucosylated hydroquinone in the culture filtrate. The HGE was successively purified by ammonium sulfate fractionation, and Q-Sepharose, Phenyl-Toyopearl, and Superose 12 column chromatographies. The molecular weight was estimated as 65 kDa by SDS-polyacrylamide gel electrophoresis, and 54 kDa by gel filtration. Based on an analysis of the hydrolytic products from soluble starch, HGE was considered to be a kind of α-amylase. The structure of the hydroquinone glucoside produced by HGE was identified as $\text{4-}\text{hydroxyphenyl}\text{-O-α-}\text{d}\text{-glucopyranoside}$ by α- and β-glucosidase treatments, and ¹H-NMR and ¹³C-NMR.