Effect of different level of substrate on lipase production by wild-type (Isl-9) and mutant strain (EM-7) of R. oligosporus. Distilled water 10 ml, time of incubation 72 h, temperature 30°C. --, Wild-type Isl-9; -Ο-, Mutant strain EM-7. Y-error bars state standard deviation (±SD 5%) among the values of three parallel replicates.