Production of thermostable pullulanase by Clostridium thermosulfurogenes SV2 in solid-state fermentation: optimization of enzyme leaching conditions using response surface methodology

The optimization of parameters for the effective leaching of thermostable p ullulanase from Clostridium thermosulfurogenes SV2-fermented bran was carri ed out using response surface methodology based on the central composite ro tatable design. The design contains a total of 54 experimental trials with the first 32 organized in a fractional factorial design and experimental tr ials from 33-40 and 51-54 involving the replication of the central points. The design was employed by selecting solvent to wheat bran ratio (S/BB), pr ocess temperature, solvent pH, shaking (RPM) and contact time (h) as model factors. Among the five independent variables studied, the S/BB, solvent pH and shaking were found to be significant. S/BB ratio of 9.0, 200 RPM shaki ng and solvent pH 6.0 were identified as optimum for the leaching of thermo stable pullulanase from the strain SV2-fermented bran.