Optimization of antioxidant exopolysaccharidess production by Bacillus licheniformis in solid state fermentation

Response surface methodology was applied to optimize physical and nutritional variables for the production of antioxidant exopolysaccharidess (EPSs) by Bacillus licheniformis UD061 in solid state fermentation with squid processing byproduct and maize cob meal used as a carbon and nitrogen source and solid matrix. The factors noted with Plackett-Burman design for optimization of EPSs production were NaCl, MgSO4·7H2O, and moisture level. These factors were further optimized using Box-Behnken design and response surface methodology. Using this methodology, the quadratic regression model of EPSs production was built. Maximum EPSs production was obtained under the optimal conditions of 4.08 g L−1 NaCl, 0.71 g L−1 MgSO4·7H2O, and 60.49% moisture level. A production of 14.68 mg gds−1, which was well in agreement with the predicted value, was achieved by this optimized procedure.