| Polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA), are well documented for their beneficial effects in human health. Shewanella putrefaciens MAC1 synthesizes high amount of EPA. Gene(s) responsible for EPA production have not been defined. To identify the EPA gene(s), random insertion strategy was used. Sixty mutants, out of 500, were screened for EPA production. Three mutants with higher EPA production and three mutants with lower EPA production were chosen to study their growth properties at different temperatures, their fatty acid profiles and genetic analysis. Mutants with higher EPA production grew faster at low temperature (0 and 4°C). Amounts of EPA precursor, docosapentaenoic acid and docosahexaenoic acid were different at different temperatures. From 10 PCR generated DNA fragments, one showed 96% homology to trimethylamine N-oxide reductase gene, one had 84% with rRNA operons of E. coli, while others had no high homology in a blast search. Based on this study, Tn5 insertion changes the regulation of EPA production. |
