Applied Biochemistry and Biotechnology, Vol.177, No.2, 346-361, 2015
Characterization and Application of Biosurfactant Produced by Bacillus licheniformis R2
The biosurfactant produced by Bacillus licheniformis R2 was characterized and studied for enhancing the heavy crude oil recovery at 80 A degrees C in coreflood experiments. The strain was found to be nonpathogenic and produced biosurfactant, reducing the surface tension of medium from 70 to 28 mN/m with 1.1 g/l yield. The biosurfactant was quite stable during exposure to elevated temperatures (85 A degrees C for 90 days), high salinity (10 % NaCl), and a wide range of pH (5-12) for 10 days. It was characterized as lipopeptide similar to lichenysin-A, with a critical micelle concentration of about 19.4 mg/l. The efficiency of crude biosurfactant for enhanced oil recovery by core flood studies revealed it to recovering additional 37.1 % oil from Berea sandstone cores at 80 A degrees C. The results are indicative of the potential for the development of lipopeptide biosurfactant-based ex situ microbial enhanced heavy oil recovery from depleting oil fields with extreme temperatures.