Alloue_2008_Prep.Biochem.Biotechnol_38_217

This work investigated the effects of monopropylene glycol, protease inhibitor, and gamma irradiation on Yarrowia lipolytica lipase stability during storage. Enzyme liquid stabilization was achieved by addition of monopropylene glycol (MPG) at respective concentrations of 50, 75, and 90%, the protease inhibitors (P2714 and P8215) at 0.1%, and the gamma irradiation with 10kGy, 15kGy, and 25kGy doses. The results showed that monopropylene glycol limited the microorganism growth and decreased the enzymatic activity at high concentration (up to 50%), at two temperatures (20 and 4 degrees C). Enzyme stored at 20 degrees C lost its activity by 80% after two months. This loss was attributed to the protease's effect. At this temperature, the protease's activities have been limited by the specific inhibitors. The gamma irradiations improve microbial safety of liquid enzyme.