[Isolation and identification of surfactin producing Bacillus subtilis strain and its effect of surfactin on crude oil].
Strains producing biological surfactants were isolated from formation water of Daqing oil field, Heilongjiang Province, China. From which a lipopeptide producing strain ZW-3 was screened out by PCR of the sfp gene. The morphology, cultural characteristics, physiological, biochemical properties and chemotaxonomy of strain ZW-3 were studied. The strain is rod shaped (0.7-0.8 microm x 2-3 microm), gram-positive, spore-forming and aerobic bacteria. Its (G+C) content was determined to be 42.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequence demonstrated that it was closely related to the genus Bacillus subtilis, and the metabolites of strain ZW-3 was analyzed by thin layer chromatography and high performance liquid chromatography, the result indicated that the biosurfactant strain ZW-3 produced was surfactin. It could reduce surface tension of bacterial fermentation culture medium and water/oil- interfacial tension from 68.82 mN/m to 24.88 mN/m and from 23.53 mN/m to 4.57 mN/m, respectively, and its mixture with 1.8% NaOH could reduce water/oil- interfacial tension to an ultra low level (1.2 x 10(-3) mN/m), Its critical micelle concentration (CMC) was tested to be 33.3 mg/L (3.24 x 10(-5) mol/L)at 25 degrees C, and it had excellent emulsifying (2.89U) and foaming property. All these results showed that this biosurfactant had great potential in pharmaceutics, environmental protection, cosmetic, oil recovery and many other application fields.
Wang
Dawei
D
Petroleum Engineering College, Daqing Petroleum Institute, Daqing 163318, China. wdw78913@163.com
Liu
Yongjian
Y
Lin
Zhongping
Z
Yang
Zhenyu
Z
Hao
Chunlei
C
D001412:Bacillus subtilis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D045703:Emulsifying Agents / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D005285:Fermentation; D055666:Lipopeptides / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry; D008823:Micelles; D010456:Peptides, Cyclic / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry; D010578:Petroleum; D010802:Phylogeny; D013500:Surface Tension; D013501:Surface-Active Agents / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*
D045703:Emulsifying Agents; D055666:Lipopeptides; D008823:Micelles; D010456:Peptides, Cyclic; D010578:Petroleum; D013501:Surface-Active Agents; C009365:surfactin peptide