Proteolytic enzyme production by isolated Serratia sp RSPB11: Role of environmental parameters

An effective proteolytic enzyme producing microbial strain has been isolated from marine habitats and evaluated its extracellular protease production properties with respect to different fermentative physiological parameters. The strain has been identified based on biochemical tests according to Bergey's Manual of Systematic Bacteriology as Serratia sp and designated as RSPB11. This strain has potential to hydrolyze chitin, gelatin and casein revealing its industrial potential for production of multi-enzyme complex. Since the isolated strain belongs to Serratia genus, the protease produced by this strain is considered as serralysin and which is not inhibited by PMSF suggesting the enzyme belongs to other than serine type of protease. Further analysis denoted that this enzyme belongs to metalloprotease which is confirmed based on negatively regulation of caseinolytic (proteolytic) activity by EDTA. The maximized enzyme production occurred at medium initially adjusted to pH 7.0 incubated at 33^oC under aerated environment. Analysis of the pH profile before and after fermentation depicted that irrespective of initial medium pH, it is shifted to pH 9.0 after fermentation suggesting the enzyme produced is alkaline in nature.