Optimization Studies for Chitinase Production from Parapeneopsis hardwickii (spear shrimp) exoskeleton by solid-state fermentation with marine isolate Citrobacter freundii str. nov. haritD11

The aim of this study was to report traditional and statistical optimization of fermentation conditions for chitinase production by a novel bacterial strain, Citrobacter freundii haritD11 isolated from marine sediment. A sequential optimization methodology comprising of traditional one-variable-at-a-time approach and response surface methodology was applied to enhance the fermentative production of chitinase under solid-state fermentation using shrimp shellfish waste. Maximum chitinase activity (128.47 U/gds) was obtained at basic optimum conditions. To improve the chitinase production activity, chosen parameters were further optimized statistically through Box–Behnken method and the critical levels of the three examined independent variables as predicted from the model are 34.6 °C of temperature, 58.19 % v/w moisture content and 2.36 % w/w yeast extract concentration. At these conditions, predicted chitinase activity of 141.787 U/gds was observed, a verification experiment was accomplished and the experimental value was 143.15 U/gds at the critical conditions predicted. Statistical optimization showed 1.1-fold of improved chitinase activity compared to traditional one-variable-at-a-time method. Hence fermentation of shrimp waste for chitinase production using Citrobacter showed biodegradation of the chitinous waste and concomitantly the enzyme was reported to have antifungal activity.