Alkaline Protease Production under Solid State Fermentation

A total of 240 alkaliphilic bacterias were isolated from samples collected from alkaline soda lakes of Ethiopia were screened for the production of alkaline proteases. Of these, 30%(80)were protease positive. Out of the 80 protease positive isolates, 20 (25%) grew well and produce appreciable level of enzyme activity when grown in solid state culture. One isolate designated as Bacillus sp.C45 was selected based on enzyme property for further study. The protease produced by Bacillus sp. C45 was characterized to determine its potential industrial application. The enzyme was active in the pH range of 6.5-11.5, with optimum activity at pH 8-9; and stable at alkaline pH. The optimum temperature for activity was 40°C and 50°C in absence and presence of 5mM of Ca+2, respectively. The enzyme also displayed appreciable dehairing activity suggesting potential application for dehairing and detergent at moderate temperatures. By using wheat bran as substrate maximum protease production was achieved at inoculum size of 20% (v/w), bran to moistening agent ratio of 1:2 when incubated at 30°C for 144 hr showing a good potential to produce low cost alkaline protease by using inexpensive substrate.