Solvent Tolerance Mechanisms in Shewanella putrefaciens IBBPo6

摘要

Shewanella putrefaciens IBBPo6 (KM405339) showed good tolerance to 5 % organic solvents. The growth was higher when S. putrefaciens IBBPo6 cells were exposed to n-decane, as compared with the growth of cells exposed to toluene, o-xylene, ethylbenzene, cyclohexane, or n-hexane. Thus, n-decane was less toxic for S. putrefaciens IBBPo6 cells, while toluene, o-xylene, ethylbenzene, cyclohexane, and n-hexane were more toxic for this bacterium. The release of nucleic acids was higher when S. putrefaciens IBBPo6 cells were exposed to toluene, o-xylene, ethylbenzene, cyclohexane, or n-hexane, as compared with the release of nucleic acids from control cells and n-decane exposed cells. The cell surface hydrophobicity increased when S. putrefaciens IBBPo6 cells were exposed to n-decane, while in the presence of toluene, o-xylene, ethylbenzene, cyclohexane, and n-hexane, a decrease in the cell surface hydrophobicity was acquired. The exposure of S. putrefaciens IBBPo6 cells to 5 % organic solvents had induced biofilms formation, and their structure differs according to the nature of the hydrophobic substrate. Two secondary metabolites (i.e., biosurfactants, carotenoids) were produced by S. putrefaciens IBBPo6 control cells, as well as by the cells exposed to 5 % organic solvents. S. putrefaciens IBBPo6 possesses alkB1 and alkM1 catabolic genes and HAE1 transporter gene. A homologue of otsA1 gene was also detected in this bacterium. Some differences between the polymerase chain reaction (PCR) patterns of S. putrefaciens IBBPo6 control cells and cells exposed to 5 % organic solvents were observed. Distinct repetitive sequence-based PCR (rep-PCR), random amplification of DNA fragments (RAPD), and amplified ribosomal DNA restriction analysis (ARDRA) patterns were also acquired in S. putrefaciens IBBPo6 cells exposed to 5 % organic solvents, compared with the control cells.