Bacillus sphaericus. an obligate alkalophile, overproduces extracellular alkaline proteases. Kinetics of growth and protease production by this organism were analyzed to identify parameters that control protease synthesis. Results showed protease production to be both growth and non-growth associated although a major portion of the enzyme was secreted in post exponential phases. The initial concentration of glucose and nitrogen sources significantly affected cell growth and enzyme secretion. Fed-batch cultures were performed to maximize protease activity in a bioreactor. By using suitable feeding strategies, the protease activity and its productivity in a fed-batch process was increased by 44% over that in batch process. primarily due to the longer maintenance of increased rates of growth and enzyme production by providing continuous and controlled supply of additional substrate and nutrients. (C) 2003 Elsevier Ltd. All rights reserved.