Optimization of α-amylase production from Aspergillus Niger using spoiled starch rich vegetables by response surface methodology and Genetic Algorithm

Abstract

Optimization of process variables for the improvement of α-amylase production in the specially made starch medium from spoiled starch rich vegetables by the cultivation of Aspergillus Niger was performed using response surface methodology (RSM) and genetic algorithm. Cultivation of Aspergillus Niger was conducted in submerged fermentation in the starch medium. Initially, the effect of incubation time (12–72 hours), pH (4–8), Temperature (25–450C), starch concentration (5–25 mg/ml) and Inoculum size (5–25 %) on two objectives, i.e. total amount of crude enzyme and its activity was examined. It is observed that process variables were found to have a significant influence on the enzyme production. Multi-objective optimization of process variables found from central composite design were-incubation time (60 hrs), pH (6), Temperature (350C), Starch Concentration (15 mg/ml) and Inoculum size (15%). At these variables, maximum enzyme activity and concentration of protein were 94 IU/ml and 8.27 mg/ml respectively. The optimum process variables found from Genetic Algorithm (GA) were-Incubation time-68hrs, pH-7, Temperature-350C, Starch Concentration-19 mg/ml and Inoculum size-20%. At these variables, maximum concentration of protein and its activity were 8.60 mg/ml and 90IU/ml respectively.