Streptomyces lavendulae NCIM 2421 culture produced both extracellular and intracellular cholesterol oxidase (COD), 1.5% potato starch was good substrate for enzyme production. An extracellular enzyme activity of 2.0 U/ml in 72 h fermentation was achieved, during the stationary phase. The culture also produced an intracellular COD of 104.3 U in 100 ml broth. An enzyme recovery of 90% was possible by ultrafiltration and 83% by (NH4)(2)SO4 precipitation. The COD produced in the fermentation broth, was stable over a pH range of 6-10 for 1 h, and when heated up to 50degreesC for half hour it retained 65% of the original activity. The shelf life of enzyme was 5 days at room temperature and 2 months at 4degreesC. (C) 2003 Elsevier Inc. All rights reserved.