Single cell protein production from digested and undigested poultry litter by Candida utilis: optimization of process parameters using response surface methodology

In this study, production of single cell protein (SCP) was carried out using Candida utilis from undigested poultry litter (UPL) and digested poultry litter (DPL). UPL and DPL were hydrolyzed by acid hydrolysis initially and the resulting crude hydrolysates were used for SCP production. Fermentation variables of the production medium were optimized by single variables optimization methodology. By this conventional approach, SCP production from UPL and DPL has increased to 25 and 20 %, respectively. The proportional analysis of these results revealed that UPL was the suitable substrate than DPL for the production of SCP by C. utilis. Further, 2 3 central composite design was applied to determine the optimal process parameters for SCP production using UPL as substrate. The analysis of treatment combinations showed that a second-order polynomial regression model was in good agreement with experimental results at R 2 value −0.98 ( P