Production of alkaline protease by rhizospheric Bacillus cereus HP_RZ17 and Paenibacillus xylanilyticus HP_RZ19

Alkaline protease of microbial sources is remarkably stable, highly active, and produced conveniently at a large-scale in a more cost-effective way. Owing to higher activity and more stability at alkaline pH, the enzyme has attracted significant commercial interest in many fields. Although alkaline protease is produced by a large number of microbes; however, the search for high yielding novel strains and optimization for getting more yields are always desired. Therefore, the aim of the present research work was to search and select high yielding strains and to optimize the physicochemical parameters for better yield of alkaline protease. A total of 09 protease positive isolates were obtained from the rhizosphere of various crop plants such as peanut (Arachis hypogaea), cotton (Gossypium hirsutum), banana (Musa acuminata) and papaya (Carica papaya). Two of these isolates, namely HP_RZ17 and HP_RZ19 produced a copious amount of protease. These isolates were later identified as Bacillus cereus HP_RZ17 and Paenibacillus xylanilyticus HP_RZ19. The influence of various physicochemical factors were studied by one variable at a time (OVAT) approach where only one factor was varied keeping other factors constant and the results were statistically analyzed using the Student’s t test. The optimized protocol resulted in a 2.45 and 3.04-fold increase in the production of protease by B. cereus HP_RZ17 and P. xylanilyticus HP_RZ19, respectively.