Characterization of a novel bioemulsifier from Pseudomonas stutzeri.

This study describes a novel and efficient alasan-like bioemulsifier produced by Pseudomonas stutzeri NJtech 11-1, which was isolated from the Shengli Oilfield. The strain was found to produce a new and interesting emulsion stabilizer. The crude bioemulsifier showed super stability with 50% salinity and broad pH 3-10. The emulsion index (EI24 ) was increased to 100% after heating from 45 to 95 °C and the emulsion could be stable for at least 30 days. The yield of Ps-bioemulsifier (pure bioemulsifier) was 0.68 ± 0.05 mg mL-1 . The Ps-bioemulsifier was composed of carbohydrates (80 ± 2.6%) and proteins (9.5 ± 0.5%). A low concentration (0.2 mg mL-1 ) of the Ps-bioemulsifier was obtained maximum emulsifying activity at pH 7.1 and its emulsifying activity strengthened by suitable salinity. Furthermore, Ps-bioemulsifier could also emulsify cyclohexane, hexadecane, kerosene, xylene hydrocarbons efficiently. Therefore, the Ps-bioemulsifier showed emulsifying characteristics which make it a good candidate for potential applications in bioremediation and microbial enhanced oil recovery.