Banana peel as substrate for α-amylase production using Aspergillus niger NCIM 616 and process optimization

Amylases are well known for applications ranging from starch and food processes industry to medical applications. In the present study, the potential of banana peel was evaluated for alpha-amylase production using the fungal culture of Aspergillus niger NCIM 616 in solid submerged (SmF) and solid state (SSF) fermentation. The effect of different parameters, such as, substrate concentration, water content, layer thickness and external salt addition was studied in terms of the amylase activity. In SmF, 25% peel concentration was found optimum for the maximal amylase activity; while in SSF, 30% water content in the 3 cm thick substrate bed was optimum. The activity was also influenced by the addition of external salts and the combination of 1% NH4NO3 with 0.5% CaCl2 was found to have maximal effect. A comparative evaluation of two different fermentation systems showed 80% higher specific activity of alpha-amylase in SSF as compared to that in SmF, which clearly demonstrated the superiority of the SSF system. The study suggests that banana peel could be used as a potential raw material for alpha-amylase production.