PRODUCTION AND OPTIMIZATION OF CHOLESTEROL OXIDASE FROM RHODOCOCCUS SPECIES

Objective: Optimization of conditions for cholesterol oxidase production by the microorganism isolated from urban compost and dairy soil samples.Methods: Isolates were obtained on the basis of their capability of growing on isolation medium A and B and their cholesterol oxidase (CHO) production was estimated. CHO production was optimized by the optimization of temperature, pH, carbon sources, and organic and inorganic nitrogen sources.Results: 3 isolates out of 22 were found to secrete extracellular CHO as detected by cholesterol oxidase indicator plate A and were designated as cholesterol oxidase producing isolate 1, 2 and 3 (COP 1, COP 2 and COP 3). Results showed that the strain COP 2 belonging to the genus Rhodococcus sp. based on morphological, cultural and biochemical characteristics recorded highest cholesterol oxidase activity. Optimum temperature and pH for CHO activity were found to be 35 °C and 7.5 respectively. Steroidal substrate cholesterol produced a significant increase in CHO level (0.502 IU/ml). Organic and inorganic nitrogen sources were supplemented in combinations leads to increase in CHO production as compared to individual components. (NH4)2HPO4 and yeast extract supported the highest enzyme production (0.574 IU/ml).Conclusion: The isolate COP 2 produced significant levels of cholesterol oxidase extracellularly in optimized medium as compared to cell bound CHO, and can be easily produced on an industrial scale.Â