This study aimed to develop viable enzymes for bioconversion of resveratrol-glucoside into resveratrol. Out of 13 bacterial strains tested, Lactobacillus kimchi JB301 could completely convert polydatin into resveratrol. The purified enzyme had an optimum temperature of 30-40 degrees C and optimum pH of pH 5.0 against polydatin. This enzyme showed high substrate specificities towards different substrates in the following order: isorhaponticin "polydatin" mulberroside A > oxyresveratrol-3-O-glucoside. Additionally, it rarely hydrolyzed astringin and desoxyrhaponticin. Based on these catalytic specificities, we suggest this enzyme be named stilbene glucoside-specific beta-glucosidase. Furthermore, polydatin extracts from Polygonum cuspidatum were successfully converted to resveratrol with a high yield (of over 99%). Stilbene glucoside-specific beta-glucosidase is the first enzyme isolated from lactic acid bacteria capable of bio-converting various stilbene glucosides into stilbene. (C) 2014 Elsevier Inc. All rights reserved.