[Construction and evaluation of an engineered bacterial strain for producing lipopeptide under anoxic conditions]

Ying Yong Sheng Tai Xue Bao. 2015 Aug;26(8):2553-60.
[Article in Chinese]

Abstract

Biosurfactant-facilitated oil recovery is one of the most important aspects of microbial enhanced oil recovery (MEOR). However, the biosurfactant production by biosurfactant-producing microorganisms, most of which are aerobes, is severely suppressed due to the in-situ anoxic conditions within oil reservoirs. In this research, we successfully engineered a strain JD-3, which could grow rapidly and produce lipopeptide under anoxic conditions, by protoplast confusion using a Bacillus amyloliquefaciens strain BQ-2 which produces biosurfactant aerobically, and a facultative anaerobic Pseudomonas stutzeri strain DQ-1 as parent strains. The alignment of 16S rDNA sequence (99% similarity) and comparisons of cell colony morphology showed that fusant JD-3 was closer to the parental strain B. amyloliquefaciens BQ-2. The surface tension of culture broth of fusant JD-3, after 36-hour cultivation under anaerobic conditions, decreased from initially 63.0 to 32.5 mN · m(-1). The results of thin layer chromatography and infrared spectrum analysis demonstrated that the biosurfactant produced by JD-3 was lipopeptide. The surface-active lipopeptide had a low critical micelle concentration (CMC) of 90 mg · L(-1) and presented a good ability to emulsify various hydrocarbons such as crude oil, liquid paraffin, and kerosene. Strain JD-3 could utilize peptone as nitrogen source and sucrose, glucose, glycerin or other common organics as carbon sources for anaerobic lipopeptide synthesis. The subculture of fusant JD-3 showed a stable lipopeptide-producing ability even after ten serial passages. All these results indicated that fusant JD-3 holds a great potential to microbially enhance oil recovery under anoxic conditions.

MeSH terms

  • Bacillus / genetics
  • Bacillus / metabolism*
  • Biodegradation, Environmental
  • Carbon / metabolism
  • Hydrocarbons / metabolism
  • Lipopeptides / biosynthesis*
  • Nitrogen / metabolism
  • Organisms, Genetically Modified
  • Petroleum / metabolism
  • Surface Tension
  • Surface-Active Agents / metabolism*

Substances

  • Hydrocarbons
  • Lipopeptides
  • Petroleum
  • Surface-Active Agents
  • Carbon
  • Nitrogen