PRODUCTION OF ORGANIC AND INORGANIC SELENIUM COMPOUNDS BY LACTIC ACID BACTERIA

摘要

A novel strain of lactic acid bacteria was found to be heat resistant and able to grow in a sulfur-limiting medium (SLM) containing a high concentration of sodium selenite. The microorganism is a non-spore forming and Gram-positive coccus, which is identified with >90% confidence using the API biochemical and sugar fermentation tests, ribotyoing and 16S rRNA sequencing as Pediococcus pentosaceus SP80. In the current study, P. pentosaceus SP80 grown on SLM containing 250 ppm sodium selenite produced both organic and inorganic forms of selenium. These selenium compounds can be separated using an anion exchange chromatography technique. The concentrations of selenium detected in the organic and inorganic fractions were 4.34 and 21.7 ppm, respectively. Selenium-enriched bacteria are useful as a source of selenium for supplementing the diets of animals and humans. Animals fed efficacious amounts of the selenium-enriched bacteria show improved feed conversion rates and higher levels of glutathione peroxidase (GPx) activity in heart, kidney and liver tissues indicating an increased absorption and retention of selenium over control diets.