ENHANCED PRODUCTION OF EXTRACELLULAR LIPASE BY NOVEL MUTANT STRAIN OF ASPERGILLUS NIGER

Twelve fungal strains belonging to 9 different species of genera Aspergillus, Pencilillium, Trichoderma and Mucor were screened for extracellular lipase production. The most active lipase producing strain A. niger was selected for strain improvement by induced mutagenesis with UV light and N-methyl-N-nitro-N-nitrosoguanidine (NMG). Chemical mutagenesis was found to be more effective in comparison to the physical one. By two stages mutagenesis with 200 mu g cm(-3) NMG for 4 h, lipase activity of parental strain was enhanced more than two times. The selected mutant A. niger NMG(12/4) was stable and maximum lipase activity of 15.5 U cm(-3) was reached at 96 h, which corresponded to the end of the exponential growth phase. The selected mutant is prospective for the development of industrial biotechnology for production of extracellular lipase.