Spore-Forming Lactic Acid-Producing Bacterium Bacillus coagulans Synthesizes and Excretes Spermidine into the Extracellular Space.

The effect of spermidine in extending healthy longevity has attracted attention. As people age, their ability to synthesize putrescine, the precursor of spermidine, declines, and its supplementation from the diet or gut bacteria is needed. Many bacteria synthesize spermidine, but no strains have been reported to excrete de novo synthesized spermidine from the cells. We found that Bacillus coagulans strain YF1, isolated from "nanohana-duke", excreted de novo synthesized spermidine from the cells under anaerobic conditions. This strain synthesizes spermidine from arginine via agmatine, putrescine, and carboxyspermidine in sequential reactions, and the genes encoding the enzymes responsible for these reactions have been identified. B. coagulans is a gastric acid-resistant spore-forming lactic acid-producing bacterium, known for its beneficial effects as a probiotic. It can be used to produce lactic acid fermented foods containing spermidine. The newly discovered ability to excrete de novo synthesized spermidine is the decisive feature of this bacterium.