Transcriptional Profiling Suggests that Multiple Metabolic Adaptations are Required for Effective Proliferation of <i>Pseudomonas aeruginosa</i> in Jet Fuel

Fuel is a harsh environment for microbial growth. However, some bacteria can grow well due to their adaptive mechanisms. Our goal was to characterize the adaptations required for Pseudomonas aeruginosa proliferation in fuel. We have used DNA-microarrays and RT-PCR to characterize the transcriptional response of P. aeruginosa to fuel. Transcriptomics revealed that genes essential for medium- and long-chain <i>n</i>-alkane degradation including <i>alkB1</i> and <i>alkB2</i> were transcriptionally induced. Gas chromatography confirmed that P. aeruginosa possesses pathways to degrade different length <i>n</i>-alkanes, favoring the use of <i>n</i>-C_11–18. Furthermore, a gamut of synergistic metabolic pathways, including porins, efflux pumps, biofilm formation, and iron transport, were transcriptionally regulated. Bioassays confirmed that efflux pumps and biofilm formation were required for growth in jet fuel. Furthermore, cell homeostasis appeared to be carefully maintained by the regulation of porins and efflux pumps. The Mex RND efflux pumps were required for fuel tolerance; blockage of these pumps precluded growth in fuel. This study provides a global understanding of the multiple metabolic adaptations required by bacteria for survival and proliferation in fuel-containing environments. This information can be applied to improve the fuel bioremediation properties of bacteria