Peanut pod-an inexpensive substrate for β-galactosidase production by Bacillus sp in solid-state fermentation: process evaluation and optimization by Taguchi design of experimental (DOE) methodology

Aim. The aim of present study was beta-galactosidase production from indigenous and inexpensive wastes under SSF conditions using statistical experimental design Methods. Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was applied to evaluate the influence of five factors (peanut pod concentration, C/N ratio, incubation time, type of solid substrate and lactose concentration) on the P-galactosidase production by Bacillus licheniformis under solid-state fermentation. Results. The results showed that peanut pod concentration, incubation time and lactose (as inducer) were found to be the most effective factor for promoting enzyme production, followed by the C/N ratio. Peanut pod 70%w/w, C/N ratio 20, incubation time 72h, wheat straw as solid substrate and lactose concentration 1%w/w the best conditions determined by the Taguchi method. Conclusion. Our finding showed that combination of peanut pod with wheat and rice straw could be used as suitable and low-cost substrate for p-galactosidase production. Also, the study shows that the Taguchi's method is suitable to optimize the experiments for the production of beta-galactosidase.