Degradation of cholesterol by Bacillus subtilis SFF34 isolated from Korean traditional fermented flatfish.

Abstract

To examine cholesterol degradation by Bacillus subtilis SFF34. Cholesterol degradation and cholesterol oxidase production by B. subtilis SFF34 were investigated in a medium containing 0.2% cholesterol. In addition, the oxidized product of cholesterol by the purified cholesterol oxidase was detected using a gas chromatograph. Cholesterol oxidase production reached its maximal level (3.14 U ml(-1) after 24 h of incubation in the cholesterol medium. The residual cholesterol content reduced to 0.98 mg g(-1) after 60 h of cultivation in the cholesterol medium. Two cholesterol oxidases were purified from the culture supernatant fluid and their reaction product against cholesterol was identified as 4-cholesten-3-one. B. subtilis SFF34 degraded cholesterol and produced a high level of extracellular cholesterol oxidase. Bacillus subtilis will be very useful for the reduction of cholesterol in many fermented foods and as a source of cholesterol oxidase.