Isolation of high lipase-producing strains and optimization of lipase producing conditions

The experiments were conducted in order to obtain high lipase-producing strains from dozens of microbial strains, including Geotrichum candidum. After the preliminary and qualitative screening in the oil medium, the lipase activity were determined by acidbase titration method. The strains which produced more lipase were isolated at last, of them Geotrichum candidum strains was also screened out, whose enzyme activity was up to 10.79 U/mL. Then further studies on the lipase producing conditions were conducted.The results show that the optimum medium formulation contained: olive oil 2%, beef extract 2%, sucrose 0.5%,(NH4)2SO40.1%. The optimum cultivate conditions were: pH 7.0, 28℃, 225 r min-1。