The ultrasonic effect on the mechanism of cholesterol oxidase production by Brevibacterium sp.

The effects of ultrasonic radiation on cholesterol oxidase production by Brevibacterium sp. are studied in this paper. An ultrasonic wave with low intensity at 20 kHz, 200 W/ cm2 was employed to study the effects of irradiation at different lengths of time on the growth of Brevibacterium sp. cells. The result showed that the production of cholesterol oxidase from Brevibacterium sp. obviously increased, and was about 18.3%, when the culture was radiated for 1 min every 4 h. In order to investigate the action ofultrasonic on cell membrane and to facilitate enzyme excretion, transmission electron microscopy (TEM) was employed. Scanning of the bacterial cells by TEM also first revealed that holes appeared in the cytoplasmic region, then excluded from the cell barrage, and finally self-destructed with higherirradiating dosage