Study on Process Optimization for Bioemulsifier Production

A useful bioemulsifier was secreted by Geobacillus sp. XS2 isolated from an oil-contaminated soil sample from Yumen oil field in northern China. The extracellular bioemulsifier was able to form a stable oil/water emulsion. The effects of different bioemulsifier concentrations on cell growth and activity of fermentation broth with water-soluble and water-insoluble carbon sources were studied. Various carbon sources, nitrogen sources, and C/N ratios were screened, and the culture conditions such as pH and ventilation were optimized through the fermentation progress. After a series of steps of optimization, the maximum bioemulsifier production reached to 21.1 g/L +/- 1.15 g/L and more than four times higher than that observed in the initial experiment. And the bacterial strain XS2 showed a good performance to adapt to the environment and strong potential for industrial applications.