The present study describes the screening and production of extracellular lipase (EC 3.1.1.3) from a Rhizopus oligosporus mutant strain developed by chemical mutagenesis. The wild-type was simultaneously treated with different concentration of EMS and MMS. Among 13 mutant variants, EM-7 showing maximum lipase activity of 71±3.55 U/g, was selected. Resistance in the hyper producing strain was developed by exposing it with low levels of L-cysteine HCl to protect it from instability. It was

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... d that under optimum conditions at 30°C temperature, pH 7, and incubation period 64 h, the lipase activity was increased up to 124±2.48 U/g. The crude enzyme was purified by ammonium sulfate precipitation method at 40 %. The molecular weight of the enzyme was found to be 33 kDa. The results showed that the enzyme produced from mutant strain gave significantly higher (p≤0.05) lipase activity than the wild-type. From the results presented in the study, it was observed that maximum lipase activity could effectively be achieved after EMS and MMS-induced mutagenesis of filamentous fungus culture used.