Biosynthesis of glycyrrhetinic acid monoglucuronide by whole-cell of Penicillium purpurogenum in an aqueous/organic system

Biosynthesis of glycyrrhetinic acid monoglucuronide (GAMG) by β-D-glucuronidase from the whole cell of Penicillium purpurogenum Li-3 in an aqueous/organic system was studied. Results showed that tert-butyl alcohol is the best organic solvent and the optimum volume ratio of aqueous to organic phase is 3 to 7. The rest optimum conditions for this biocatalysis are 1.5 g·L^-1 of substrate concentration, 45°C of temperature, pH 5.0, 7 g·L^-1 of enzyme concentration and 120 r·min^-1 of shaking rate. Under these optimized conditions, 79.12% yield of GAMG was achieved after 48 h reaction. The whole-cell enzyme has a good reusability and a high stability, which demonstrates the prospect for real application.