OptimalGrowth Medium for Production of Alkaline Protease from Industrial Wastewater and Bagasse

Alkaline proteases are used in number of industries due totheir high pH tolerance and thermal stability. In present work, Bacillus strains (Bacillus subtilisPTCC 1254, B. subtilisPTCC 1156 and B. subtilsPTCC 1715) were supplied by Persian Type Culture Collection. All strains were screened for proteolytic activity using alkaline casein agar plate, all of them showed desired alkaline proteolytic activity. Among three stains, one strain was selected for further study. The production of most bacterial proteases has always been with expensive refined substrates which tend to increase the production cost.Hence, a low-cost substrate such as starchy waste and culture conditions were capable of optimizing protease production by B.subtilis 1254. Under optimized culture conditions at pH 9, temperature 37 °C and 5% inoculum size with starchy waste (25% v/v), sugarcane bagasse (2 g/l) and corn bran (4 g/l) as carbon and nitrogen sources of the fermentation medium, maximum alkaline protease activity (83.46 U/ml) was achieved. Also the results showed that the obtained protease activity from low cost substrates was significantly higher than that from expensive substrates.

کلیدواژه ها:

Alkaline proteases ، Bacillus subtilis ، Optimization ، Low-cost substrates ، Starchy waste