目的:微生物强化采油(MEOR)对于石油开采具有成本效益和生态友好性。产生转基因生物表面活性剂的高产菌株有望用于非原位MEOR。然而,它们能否在石油储层中生存并产生生物表面活性剂以进行原位MEOR?它们对本地细菌群落有什么影响?
结果:在模拟的储层环境中,一种转基因的产生本地生物表面活性剂的菌株铜绿假单胞菌PrhlAB被生物增强。铜绿假单胞菌PrhlAB可以在模拟储层中稳定定殖。生物增强菌株PrhlAB后,在模拟储层中生产了生物表面活性剂(200mgL-1)。流体的表面张力降低到32.1mNm-1。将原油以60.1%的乳化指数乳化。生物增强菌株PrhlAB刺激了MEOR相关的微生物活性。碳氢化合物降解菌和生物表面活性剂产生菌被激活,而硫化氢产生菌受到抑制。生物增强铜绿假单胞菌PrhlAB降低了细菌群落的多样性,并逐渐简化了物种组成。具有驱油潜力的细菌成为优势属,比如Shewanella,假单胞菌和杆菌。
结论:基于培养和基于序列的分析表明,转基因生物表面活性剂产生菌株铜绿假单胞菌PrhlAB也有望用于原位MEOR。
OBJECTIVE: Microbial enhanced oil recovery (MEOR) is cost-effective and eco-friendly for oil exploitation. Genetically modified
biosurfactants-producing high-yield strains are promising for ex-situ MEOR. However, can they survive and produce
biosurfactants in petroleum reservoirs for in-situ MEOR? What is their effect on the native bacterial community?
RESULTS: A genetically modified indigenous
biosurfactants-producing strain Pseudomonas aeruginosa PrhlAB was bioaugmented in simulated reservoir environments. Pseudomonas aeruginosa PrhlAB could stably colonize in simulated reservoirs.
Biosurfactants (200 mg l-1) were produced in simulated reservoirs after bio-augmenting strain PrhlAB. The surface tension of fluid was reduced to 32.1 mN m-1. Crude oil was emulsified with an emulsification index of 60.1%. Bio-augmenting strain PrhlAB stimulated the MEOR-related microbial activities. Hydrocarbon-degrading bacteria and
biosurfactants-producing bacteria were activated, while the hydrogen sulfide-producing bacteria were inhibited. Bio-augmenting P. aeruginosa PrhlAB reduced the diversity of bacterial community, and gradually simplified the species composition. Bacteria with oil displacement potential became dominant genera, such as Shewanella, Pseudomonas, and Arcobacter.
CONCLUSIONS: Culture-based and sequence-based analyses reveal that genetically modified biosurfactants-producing strain P. aeruginosa PrhlAB are promising for in-situ MEOR as well.