Alkaline Lipase production by Acinetobacter radioresistens was investigated and the role of culture conditions was examined. The enzyme had an optimum pH of 10 and was stable over a pH range of 6-10; it could have great potential for application in the detergent industry. The optimal temperature and pH for lipase fermentation were 30 degrees C and 7, which were related to cell growth, protease formation, and stability and reactivity of lipase. A high lipase yield could be obtained during prolonged cultivation in the presence of n-hexadecane. With additional olive oil supplementation, the volumetric productivity of lipase could be improved; however, the lipase yield decreased with increasing concentrations of olive oil. The increase in the rate of lipase formation by olive oil in the presence of n-hexadecane was attributed to its enhancement of the uptake of n-hexadecane; the hydrolytic products of olive oil promoted the emulsification of n-hexadecane. Because olive oil repressed the synthesis of lipase, optimization in formulating the medium composition is considered necessary.