Statistical optimization of Lglutaminase production by Trichoderma species under solid state fermentation using African locust beans as substrate

Abstract

Six strains of Trichoderma species isolated from soil and air samples were screened for extracellular L-glutaminase production. The highest enzyme producing isolate, Trichoderma longibrachiatum was subjected to screening and nutrients optimization experiments under solid state fermentation using a constant weight of African locust beans as substrate. A specific activity of 54.96 U/mg was achieved at 1% (w/v) glutamine, 0.5% (w/v) glucose, 1% (w/v) NaCl, pH 3.0 and 1.4 ml inoculums size respectively after 3 days of incubation at 27°C as the optimum condition for L–glutaminase production. Asides glutamine, other nitrogen sources; malt extract and ammonium sulphate had a negative influence on enzyme production likewise the supplemented sources of metal ions; zinc and iron (II) ions.   Key words: Trichoderma, L-glutaminase, fermentation, African locust beans.