Isolation of the high polyamine-producing bacterium FB146 from fermented foods and identification of polyamine-related genes.

It has been reported that the intake of polyamines contributes to the extension of healthy life span in animals. Fermented foods contain high concentrations of polyamines thought to be derived from fermentation bacteria. This suggests that bacteria that produce high levels of polyamines could be isolated from fermented foods and utilized as a source of polyamines for human nutrition. In this study, FB146 was isolated from miso, a Japanese fermented bean paste, and found to have a high concentration of putrescine in its culture supernatant (452 μM). We analyzed the presence of polyamines in the culture supernatants and cells of the type strains of 21 representative species in addition to FB146, and only FB146 showed high putrescine productivity. Furthermore, whole-genome sequencing of FB146 was performed, and the ornithine decarboxylase gene (), which is involved in putrescine synthesis, and the putrescine:ornithine antiporter gene (), which is thought to contribute to the release of putrescine into the culture supernatant, were present on plasmid DNA harbored by FB146.