Lipase production by Aspergillus niger under various growth conditions using solid state fermentation

Ricinus seed litters were chosen as a cheap carbon source for lipase production by A. niger under solid state fermentation (SSF). Maximum lipase production was achieved upon using an enriched (potassium citrate and casein) waste at pH 7.8 and 30 degrees C for 8 days incubation. Nitrogen sources as NH4Cl, NH4NO3, (NH4)2SO4, urea and amino acids repressed the lipolytic activity. The chloride salts of Ba2+, Co2+, Cu2+, Fe3+, Hg2+, K+, Mg2+, Mn2+, Na+ and Sn2+ inhibited, while Zn+2 did not affect lipase production. Compounds containing hydrolyzable ester group, such as Tween(s), were found to inhibit lipase activity. When the effect of different additives such as EDTA, gum acacia, span(s), mineral and vitamins, were studied, it was found that they all exhibit decreased lipase production by the tested fungus.