Seleno-lactobacillus. An organic selenium source.

Lactic acid bacteria are nonpathogenic bacteria commonly used in food processing. An evaluation was made of the capacity to concentrate selenium in species of Lactobacillus. A selenium concentration of 1 microgram/mL in the culture medium yielded in a bacterial content of 400 micrograms/g dry biomass. Dialysis and TCA precipitation experiments of a native intracellular extract proved that at least 80% of the total selenium is associated with organic molecules. Seleno-cysteine was identified as the only seleno-amino acid present in the intracellular selenoproteins. This study shows that species of the lactic acid bacteria are able to concentrate selenium intracellular as seleno-cysteine, which could be applied in supplementation studies.