Characterization of a Blend-Biosurfactant of Glycolipid and Lipopeptide Produced by Bacillus subtilis TU2 Isolated from Underground Oil-Extraction Wastewater

• Published in: Journal of microbiology and biotechnology Vol. 23; no. 3; pp. 390 - 396
• Main Authors: Cheng, Fangyu, Tang, Cheng, Yang, Huan, Yu, Huimin, Chen, Yu, Shen, Zhongyao
• Format: Journal Article
• Language: Korean
• Published: 한국미생물생명공학회 30-03-2013
• Subjects: Biosurfactant; enhanced oil recovery; glycolipid; lipopeptide; oil-extraction wastewater; Biosurfactant; enhanced oil recovery (EOR); glycolipid; oil-extraction wastewater; lipopeptide
• ISSN: 1017-7825; 1738-8872

Biosurfactants have versatile properties and potential industrial applications. A new producer, B. subtilis TU2, was isolated from the underground oil-extraction wastewater of Shengli Oilfield, China. Preliminary flask culture showed that the titer of biosurfactant obtained from the broth of TU2 was ~1.5 g/l at 48 h (718 mg/l after purification), with a reduced surface tension of 32.5 mN/m. The critical micelle concentration was measured as 50 mg/l and the surface tension maintained stability in solution with 50 g/l NaCl and 16 g/l CaCl2 after 5 days of incubation at 70oC. FT-IR spectra exhibited the structure information of both glycolipid and lipopeptide. MALDI-TOF-MS analyses confirmed that the biosurfactant produced by B. subtilis TU2 was a blend of glycolipid and lipopeptide, including rhamnolipid, surfactin, and fengycin. The blended biosurfactant showed 86% of oil-washing efficiency and fine emulsification activity on crude oil, suggesting its potential application in enhanced oil recovery.