Enhanced Production Of Alkaline Protease By Bacillus Subtilis In Submerged Fermentation

Abstract

An alkaline protease producing strain was isolated from the sample collected from a slaughter house in Krishnagiri (District), T.N., India identified as Bacillus subtilis. Optimization of process parameters, surfactants as stimulants and strain improvement by UV for increased production of protease was carried out. Further the enzyme was partially purified and characterized. The most important factors such as temperature, pH, incubation period, carbon, nitrogen and trace elements were optimum at 35 °C, 12, 24 h, glucose, urea and MgSO₄, respectively. Addition of surfactants such as Tween 20 (75%), Tween 80 (25%), sodium taurocholate (35%) and SDS (55%) resulted in an increase in the yield of protease when added after 18 h of incubation of culture. On the other hand Triton X-100 inhibited the enzyme production.  A 29% increase in protease production was observed by mutant strain upon UV treatment (260nm) of the parent strain for 10 min. The specific activities of the enzyme in culture supernatant and partially purified (80% saturation) samples were 0.7 and 0.6 U/mg of protein, respectively. There is an increase of 6 folds purity of protease with the recovery of 80% yield. The temperature and pH optimum of purified protease were 70 °C and 12, respectively.