MICROBIAL-PRODUCTION OF GLYCYRRHETIC ACID 3-0-MONO-BETA-D-GLUCURONIDEFROM GLYCYRRHIZIN BY CRYPTOCOCCUS-MAGNUS MG-27

It was found that Cryptococcus magnus MG-27, a yeast isolated from soi l, selectively hydrolyzed the terminal beta-glucuronyl linkage of glyc yrrhizin (1) to yield glycyrrhetic acid 3-0-mono-beta-D-glucuronide (M GGR, 3), a potent sweetener (relative sweetness to sucrose: x 941). Th e conditions for cultivation of this yeast with the maximum hydrolytic activity as well as the reaction conditions of 1 with the cells for t he maximum yield of 3 were investigated. Based on the results, strain MG-27 was cultivated with a medium composed of 1.0% 1, 1.0% glucose, 0 .5% Polypepton, and 0.3% yeast extract at 28-degrees-C for 24 h. The r eaction of the resulting cells and 1 at pH 5.7 at 45-degrees-C for 48 h afforded 3 in a yield of 95%.