Optimization of Liquid Fermentation Conditions for Protease Production from Rhizomucor miehei Using Response Surface Methodology

Abstract

The research aimed to optimize the conditions of protease production from local isolate of Rhizomucor miehei in liquid medium using Response Surface Methodology (RSM). The design included the effect of five factors: fermentation time, temperature, pH, glucose concentration and casein concentration. Their optimal values were determined depending on the quantity and activity of the produced enzyme. The protein content, milk clotting activity (MCA), specific activity, proteolytic activity (PA) and (MCA/PA) ratio of the extracted enzyme were calculated to evaluate the quality of the enzyme. The optimal conditions were found to be 89.94 hours, 40.91 ̊C, 5.99, 39.09 g/L, 1.02 % for fermentation period, temperature, initial pH, glucose, and casein concentration respectively. 

The performed fermentation process under the optimized conditions gave an enzymatic extract with the values of 3.92 mg/mL, 1191.18 SU/mL, 303.87 SU/mg, 0.97 PU/mg, 314.30 for protein content, milk clotting activity, specific clotting activity, specific Proteolytic activity, and (MCA/PA) ratio respectively.