10.22376/ijpbs.2019.10.1.p1-12 Volume 9 Issue 3 2018 (July-September) Alkaline protease producing lessThan i greaterThan Bacillus subtilis lessThan /i greaterThan strain AJ was isolated from the saltern pond at South West Coast of India. The process parameters were optimized to enhance the production of alkaline protease. The nutritional factors such as, carbon, nitrogen and ions, and also physical factors such as, NaCl, pH and temperature were optimized for the maximum yield of alkaline protease. Enzyme production was maximum in the culture medium containing 4% NaCl and over a broad pH range (pH 6.0 to 9.0). The tested protease activity showed a linear increase with increase in medium temperature up to 35 ºC and at higher temperatures, the enzyme production declined. In lessThan i greaterThan B. subtilis lessThan /i greaterThan strain AJ, supplementation of glucose, sucrose, fructose, trehalose and starch significantly enhanced more amount of enzyme production than that of control. Among the tested nitrogen sources, yeast extract showed maximum amount of protease activity. The ions, Mn lessThan sup greaterThan 2+ lessThan /sup greaterThan , Na lessThan sub greaterThan 2 lessThan /sub greaterThan HPO lessThan sub greaterThan 4 lessThan /sub greaterThan and Ca lessThan sup greaterThan 2+ lessThan /sup greaterThan also enhanced enzyme production. In the present study, the chromium level of control tannery wastewater was 1712 mg/l. However the biological treatment reduced chromium level after 24h (43±2.6%) and 48 h (71 ± 4.8%) of treatment with the bacterium, lessThan i greaterThan B. subtilis lessThan /i greaterThan strain AJ. This chromium reduction was mainly due to the metabolic activity of the selected lessThan i greaterThan B. subtilis lessThan /i greaterThan strain AJ. R. AJI AND R. RAJA JEYASEKAR Bacillus subtilis strain AJ, keratinolytic protease, optimization, response surface methodology, tannery, chromium 163-171