Abstract

The effects of ultrasonic radiation on cholesterol oxidase production byBrevibacterium 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 of ultrasonic 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 higher irradiating dosage.

Key words: Ultrasonic, cholesterol oxidase, permeability, transmission electron microscope.

Abbreviation

TEM, Transmission electron microscopy; COD, cholesterol oxidase; FAD, flavin adenine dinucleotide.