Nutraceutical production by propionibacteria

Propionibacteria are able to produce a wide variety of food components that are benificial to the human health. First of all, because of its unique metabolism, Propionibacterium contains a wide variety of co-factors, mainly involved in transfer and rearrangement of C1-compounds. This microorganism has been known for decades as an efficient vitamin B-12 (deoxy adenosyl cobalamin) producer. In this contribution, a new fermentation strategy is described leading to fermentation broths with high levels of this vitamin. In addition, some strains within the Propionibacterium genus can produce large amounts of folic acid. Other potential beneficial or nutritional ingredients produced by these bacteria are anti-microbial compounds such as propionic acid and bacteriocins. Propionic acid is reported to have potent growth-inhibiting effects on fungi and as such the Propionibacterium fermentation has great potential in food preservation. In addition, several bacteriocins have been found to be produced by these bacteria such as propionicin PLG-1 and jenseniin G, acting against a variety of Gram(+) bacteria. Finally, the production of high (intracellular) levels of the low-calorie sugar trehalose is reported. This sugar, presumably, functions as compatible solute in this bacterium and certain strains accumulate huge amounts under selected conditions. The possibility for application of this metabolism are discussed.