Chitooligomers preparation by chitosanase produced under solid state fermentation using shrimp by-products as substrate

• Solid state fermentation process for chitosanase production using shrimp by-products.
• Optimized chitosanase production using response surface methodology.
• We achieved highest level of enzyme activity of 41.8 ± 0.7 U/g IDS after optimization.
• We achieved the production of 4.43 mM chitooligomers from chitosan digestion.
• A sustainable process for valorization of the seafood processing shrimp by-products.

Solid state fermentation (SSF) conditions were statistically optimized for the production of chitosanase by Purpureocillium lilacinum CFRNT12 using shrimp by-products as substrate. Central composite design and response surface methodology were applied to evaluate the effect of variables and their optimization. Incubation temperature, incubation time, concentration of inoculum and yeast extract were found to influence the chitosanase production significantly. The R2 value of 0.94 indicates the aptness of the model. The level of variables for optimal production of chitosanase was 32 ± 1 °C temperature, 96 h incubation, 10.5% (w/v) inoculum, 1.05% (w/w) yeast extract and 65% (w/w) moisture content. The chitosanase production was found to increase from 2.34 ± 0.07 to 41.78 ± 0.73 units/g initial dry substrate after optimization. The crude chitosanase produced 4.43 mM of chitooligomers as exclusive end product from colloidal chitosan hydrolysis. These results indicate the potential of P. lilacinum CFRNT12 for the chitosanase production employing cost effective SSF using shrimp by-products.