Production of Alkaline Protease Using Industrial Waste Effluent as Low-cost Fermentation Substrate

Alkaline proteases are the most important groups of commercial enzymes, which have been broadly used in industrial processes. In this study, Bacillus sp. PTCC ۱۵۳۸ was selected as a biological agent to produce alkaline protease. Enzyme production under submerge fermentation using industrial waste effluent was investigated. Since the costs of the raw material plays an important role in the cost of enzyme production, corn steep liquor (CSL) was selected as a low-cost substrate to reduce the cost of enzyme production. Various carbon sources were used as the auxiliary substrates to enhance enzyme production. Results showed that maximum enzyme activity was obtained when wheat bran was used as an auxiliary substrate. Optimal media composition and growth conditions for alkaline protease production were defined. The optimum conditions were found to be pH ۸, incubation temperature of ۳۷ °C, CSL inoculum size of ۵ v/v %, yeast extract and wheat bran concentrations of ۲ and ۶ g/l, respectively. CaCl۲ was used as an activator to enhance proteolytic activity of the enzyme. Under optimum condition, enzyme activity of ۱۰۰.۷ U/ml was obtained at CaCl۲ concentration of ۱.۵ g/l.

Keywords:

Alkaline protease , Bacillus sp , Fermentation , Low-cost substrate , Waste effluent