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Heterologous production of P seudomonas aeruginosa rhamnolipid under anaerobic conditions for microbial enhanced oil recovery
Author(s) -
Zhao F.,
Shi R.,
Zhao J.,
Li G.,
Bai X.,
Han S.,
Zhang Y.
Publication year - 2015
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12698
Subject(s) - chinese academy of sciences , china , beijing , ecology , environmental pollution , geography , environmental protection , biology , archaeology
Aims The ex situ application of rhamnolipid to enhance oil recovery is costly and complex in terms of rhamnolipid production and transportation, while in situ production of rhamnolipid is restricted by the oxygen‐deficient environments of oil reservoirs. To overcome the oxygen‐limiting conditions and to circumvent the complex regulation of rhamnolipid biosynthesis in Pseudomonas aeruginosa , an engineered strain Pseudomonas stutzeri Rhl was constructed for heterologous production of rhamnolipid under anaerobic conditions. Methods and Results The rhlABRI genes for rhamnolipid biosynthesis were cloned into a facultative anaerobic strain Ps. stutzeri DQ1 to construct the engineered strain Rhl. Anaerobic production of rhamnolipid was confirmed by thin layer chromatography and Fourier transform infrared analysis. Rhamnolipid product reduced the air–water surface tension to 30·3 mN m −1 and the oil–water interfacial tension to 0·169 mN m −1 . Rhl produced rhamnolipid of 1·61 g l −1 using glycerol as the carbon source. Rhl anaerobic culture emulsified crude oil up to EI 24 ≈ 74. An extra 9·8% of original crude oil was displaced by Rhl in the core flooding test. Conclusions Strain Rhl achieved anaerobic production of rhamnolipid and worked well for enhanced oil recovery in the core flooding model. The rhamnolipid produced by Rhl was similar to that of the donor strain SQ 6. Significance and Impact of the Study This is the first study to achieve anaerobic and heterologous production of rhamnolipid. Results demonstrated the potential feasibility of Rhl as a promising strain to enhance oil recovery through anaerobic production of rhamnolipid.