Extra-cellular l-glutaminase production by Zygosaccharomyces rouxii under solid-state fermentation

Abstract

Solid-state fermentation (SSF) was carried out for the production of extra-cellular l-glutaminase by the saline tolerant yeast Zygosaccharomyces rouxii NRRL-Y 2547 using two agro-industrial substrates, wheat bran and sesamum oil cake, which were selected after a screening of four substrates and two moistening media (sea water and 10% NaCl in tap water). Results showed better efficiency of NaCl medium for wheat bran and seawater for sesamum oil cake. Maximum l-glutaminase titres (7.5 and 11.61 U/g dry substrate- gds in comparison to 2.2 and 2.17 U/gds as initial values for wheat bran and sesamum oil cake, respectively) were produced when SSF was carried out with 64.2% initial moisture content of the substrate, 2 ml of 48 h old inoculum, 30 °C as incubation temperature and 48 h of incubation period in both the substrates, which were 3.5- and 5-times higher than the initial production for wheat bran and sesamum oil cake, respectively. External supplementation of fermentation medium with various organic and inorganic nitrogen sources was of no benefit for enzyme production.