Enhancement of Inulinase and Invertase Production from a Newly Isolated Candida guilliermondii TISTR 584

Abstract

The optimization of inulinase and invertase production from Candida guilliermondii TISTR 5844 was studied using a central composite design with four factors: pH, temperature, inoculum and substrate concentrations. The most significant factors influencing invertase production were pH and temperature with an R² value of 0.822 (P < 0.05). Unexpectedly, the R² value for inulinase production was 0.555 (P > 0.05) and there was no significant influence of the tested factors over the production of inulinase. The results obtained from the experimental design using one factor at a time demonstrated the optimum carbon and nitrogen sources for both enzymes were inulin and NH4Cl, respectively. Optimization by Taguchi methodology further indicated the optimum medium compositions for the production of inulinase (inulin concentration 1%, NH₄Cl concentration 2.4%, Mg₂SO₄•7H₂O concentration 1.2% and pH 5) and invertase (inulin concentration 5%, NH₄Cl concentration 4.8%, Mg₂SO₄•7H₂O concentration 1.2% and pH 6).