Optimization of Process Parameters for Alkaline Protease Production by Bacillus licheniformis N-2 and Kinetics Studies in Batch Fermentation

Authors : Muhammad NADEEM, Javed Iqbal QAZI, QuratulAin SYED, Shahjahan BAIG

Pages : 243-251

View : 13 | Download : 8

Publication Date : 2008-12-01

Article Type : Research Paper

Abstract :Production of alkaline protease from B. licheniformis N-2 was studied in shake flask experiments in growth medium comprised of insert ignore into journalissuearticles values(g/l);: glucose, 10; soybean meal, 10; K2HPO4, 5; MgSO4.7H2O, 0.5; NaCl, 0.5; CaCl2.2H2O, 0.5. Different process parameters, such as fermentation period, initial pH, incubation temperature, agitation speed, and size and age of inoculum, were optimized for the maximum yield of the alkaline protease. Maximum enzyme production insert ignore into journalissuearticles values(991.04 PU/ml); was obtained after 24 h of incubation at 37 °C in growth medium of pH 10. The optimum inoculum size and age were determined as 2.0% insert ignore into journalissuearticles values(v/v); and 24 h, respectively. Kinetics of growth and protease production by this microorganism were also analyzed at all optimum conditions. Biomass insert ignore into journalissuearticles values(Yx/s); and product yield insert ignore into journalissuearticles values(Yp/s); coefficients were determined as 0.375 g of cells/g of glucose and 99.3 PU/g of glucose, with a growth rate of insert ignore into journalissuearticles values(0.215 h-1); after 24 h of incubation. Thereafter, a continuous decrease in biomass and product yield was observed. The results indicate that enzyme production by B. licheniformis N-2 was entirely growth-associated and that a major portion of the enzyme was secreted in the post exponential phase.
Keywords : Process parameters, growth kinetics, alkaline protease, Bacillus licheniformis N 2