Optimization of conditions for glucose oxidase production from Aspergillus niger
2001
Zubair, H.
The main project was planned for the optimum production of glucose oxidizes from rice polishing by Aspergillus niger. Different conditions like fermentation period, substrate level, effect of pH, varying concentrations of urea, MgSO4.7H2O, CaCO3, and KH2PO4 were optimized by conducting different experiments. The growth medium of the rice polishing was fermented by Aspergillus niger with continuous shaking (120 rpm) at pH 4 and 30C for 36 hours. The fermented growth medium was blended for 15 minutes with short intermissions (3 min.) and then centrifuged at 10,000 rpm-at 5-10(C for 15 minutes. The filtrate was then subjected to enzyme assay. The maximum activity of glucose oxidise (0.342 O.D.) was recorded after 36 hours continues shaking fermentation (120 rpm) of optimum growth medium containing 2.0% rice polishing, 0.3% urea, 0.05% CaCO3 and 0.4% KH2PO4 at pH4 and 30(C. It was observed that addition of urea, CaCO3 and KH2PO4 in the growth medium of rice polishing enhanced the glucose exidase production by Aspergillus niger whereas addition MgSO4. 7H2O into the growth medium of rice polishing results in the decreased glucose oxidize production. It was therefore recommended that MgSO4 7H20 should not be added in the growth medium of rice polishing for glucose oxidase, production. The glucose oxidase was found to be quite active up to 60C with optimum temperature of 30(C. Optimum pH for glucose oxidase activity was found to be 6.0. The glucose oxidase production by Aspergillus niger in rice polishing growth medium gave reasonable yield of the enzyme. Since peroxidase was used in glucose oxidase assay therefore, isolated and purified through ammonium sulphate precipitation.
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