Production of alpha-glucosidase inhibitor by beta-glucosidase inhibitor-producing Bacillus lentimorbus B-6

Abstract

A soil microorganism producing alpha- and beta-glucosidase inhibitors was identified as Bacillus lentimorbus, based on the fatty acid and morphological analyses, along with biochemical and physiological tests. The alpha-glucosidase inhibitor was highly produced by this strain in a culture medium containing 0.25% of sodium glutamate and 0.5% of glucose, pH 8.0 at 30degreesC for 2 days. The alpha-glucosidase inhibitor from culture filtrate of this strain was identified as water soluble, organic solvent nonextractable, and heat stable. In addition to alpha-glucosidase inhibitor, this strain also produced beta-glucosidase inhibitor in the same culture medium and this inhibitor showed an antifugal activity against Botrytis cinerea. While the production of alpha-glucosidase inhibitor was decreased by a glucose concentration higher than 1%, the production of beta-glucosidase inhibitor was not influenced by a glucose concentration higher than 20%. The alpha-glucosidase inhibitor from culture filtrate of this strain was separated from the beta-glucosidase inhibitor through Sephadex G-100 column chromatography.