The kinetics of cholesterol oxidase synthesis by Nocardia rhodocrous

The production of cholesterol oxidase by 3 liter batch cultures of Nocardia rhodocrous growing on a glycerol/yeast extract medium was investigated. Cholesterol was shown to be a good inducer of the enzyme. The optimum time for cholesterol addition and the quantity to be added were determined, resulting in a 15‐fold yield increase. Cholesterol oxidase synthesis was influenced by the dissolved oxygen tension. Maximum cholesterol oxidase production was obtained at 30–40% air saturation. The effect of growth conditions on the extraction of cholesterol oxidase by Triton X‐100 was investigated. The scale‐up of the fermentation to 800 liters in a pilot‐plant fermenter is described.