Chromosomal integration of red fluorescent protein gene in rhamnolipids-producer Pseudomonas aeruginosa SG and its application in petroleum reservoir

Abstract:

[Background] Microbial transfer in oilfiled production facilities is closely related to reservoir microbial community compositions and microbiologically improved oil production process. However, it is hard to distinguish the targeted microorganisms from the numerous indigenous microorganisms containing the same specific genes. Therefore, constructing microorganisms with specific gene marks is necessary. [Objective] In order to effectively track microbial transfer in oilfiled production facilities, an engineering strain Pseudomonas aeruginosa SG-rfp containing specific mark gene was constructed. [Methods] The red fluorescent protein gene (rfp) with a constitutive promoter was inserted into amp gene encoding β-lactamase on chromosome of rhamnolipids-producer P. aeruginosa SG isolated from petroleum reservoir by homologous recombination using integration vector pEX18Gm-URD and amp gene. [Results] P. aeruginosa SG-rfp constitutively expressing rfp gene was constructed. Strain SG-rfp is intolerant of ampicillin, kanamycin, streptomycin, and gentamicin. As well as the wild-type strain SG, SG-rfp can produce biosurfactants in aerobic and anaerobic conditions and significantly enhance oil recovery efficiency from oil-bearing core. Using strain SG-rfp, diffusion-limited microbial transfer in oil-bearing porous media was investigated and demonstrated via core-flooding test. [Conclusion] This study provides a powerful tool for in-depth investigation of microbial transfer in oilfiled production facilities and microbiologically improved oil production process.