A NEW MICROORGANISM PRODUCING A GLUCOSYL TRANSFER ENZYME TO POLYPHENOLS

A microorganism producing a glucosyl transfer enzyme to hydroquinone was isolated from soil and identified as Bacillus subtilis according to its taxonomical characteristics. The enzyme (GSase) was purified from the culture filtrate by column chromatographies, including affinity chromatography using Amylostatin-immobilized Sepharose 4B. The final preparation showed a single band on SDS polyacrylamide gel electrophoresis, the molecular weight being 67 kDa. Its optimum pH far starch dextrinization was 7, while that for glucosyl transferring activity was 6, pH stability was 5-8, and isoelectric point was 5.1. GSase was not activated by Ca2+. It used malto-oligosaccharides and dextrin as well as soluble starch more effectively than maltose as glucose donors. It did not catalyze cyclodextrination from starch. GSase glucosylated various polyphenols, such as dihydroxy benzenes, hydroxy benzyl alcohols, phloroglucinol, (+)catechin, kojic acid, dihydroxy benzoic acids, caffeic acid, and gallic acid.