Culture condition optimization and the demulsification efficiency of a bacterial strain

A strain belonging to Bacillus mojavensis, with high capability of de-emulsification was isolated from contaminated oily soil in Daqing oilfield. And for O/W model emulsions, more than 83% efficiency of de-emulsification was obtained for the strain within 24h. According to the orthogonal test, the most favorable incubation conditions for growth and de-emulsification efficiency, as well as the environmental factors influencing de-emulsification efficiency of the strain were investigated. The most favorable fermentative conditions for growth were temperature were at 25°C, 160 r/min, and pH 9.0, inoculating ratio of 10%, culturing time for 40h; and that for de-emulsification occurred when temperature were at 25°C, pH 9.0, and 160 r/min, inoculating ratio of 6%, culturing time for 20h. The optimum environmental conditions for de-emulsification were followings: pH5~9, temperature of 30~50°C, the best proportion of the whole bacteria culture and O/W model emulsions was 1:5.