Culture conditions of psychrotrophic fungus, Penicillium chrysogenum and its lipase characteristics

Among 97 fungal strains from the soil collected from the high mountain areas in the Jeju Island, Korea, Penicillium chrysogenum 9 was found to be the best lipase producer. Its lipase productivity reached 42 U/ml in the culture medium. Factors affecting lipase production by Penicillium chrysogenum 9 were studied using fermentation media of different chemical compositions. Under optimal conditions we noted a 1.6-fold increase of lipase activity. The maximum lipase activity was 68 U/ml of culture medium on the 5th day of incubation at pH 6.0 and 20°C; therefore, Penicillium chrysogenum 9 was classified as a psychrotrophic microorganism. The enzyme from Penicillium chrysogenum 9 showed a maximum activity at 30°C and pH 5.0 for synthetic substrates (triacylglycerols) or at pH 7.0 for natural substrates (oils).