L-Methioninase Production by Aspergillus Flavipes from Sesame Oil Cake : Optimization by CCD

Solid-state fermentation was carried out for the production of extra-cellular L-methioninase by Aspergillus flavipes MTCC 6337 using ten agro-industrial residues. Sesame oil cake was selected as solid substrate for L-methioninase production by A. flavipes. The maximum L-methioninase yield (396 U/gds) was obtained in preliminary studies by incubating flasks containing sesame oil cake of 60% initial moisture content (pH 8.0) as substrate supplemented with D-glucose (1.0% w/v), L-methionine (0.8% w/v) , MnSO4 (0.5% w/v) and 3 ml of A. flavipes conidial suspension for 8 days at 30 0C. 4 parameters were selected for optimization by Central Composite Design (CCD) which showed significant effect on L-methioninase production in the preliminary studies. They include inoculum volume, initial moisture content, carbon supplement concentration and pH. A second order polynomial model equation was obtained. The predicted optimum levels were as follows: inoculum volume - 3.0814 ml, initial moisture content - 62.19003% (v/w), carbon supplement concentration - 0.9995% (w/v) and pH - 8.36124.The enzyme L-methioninase was partially purified using 70% saturated ammonium sulphate followed by dialysis.