Abstract: The selenium enrichment in Lactobacillus rhamnosus (ATCC 53103) was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The strains were stressed with 6% NaCl, the sodium selenite was added in an amount of 10 μg/mL, and the selenium-rich culture was carried out at pH 6.4 and 37 ℃. The selenium enrichment amount was up to 452.43 μg/g, and the selenium enrichment rate was up to 43.33%. Compared with the unstressed treatment, the selenium enrichment and selenium enrichment rate were improved 122.72 μg/g and 13.17%, respectively. The black microparticles in the body and outside of the selenium-enriched Lactobacillus rhamnosus were observed by transmission electron microscopy, which was proved to be selenium element by energy spectrum. The selenium content increased after salt stress, which further proved that salt stress promoted the selenium enrichment of Lactobacillus rhamnosus.

Key words: Lactobacillus rhamnosus, selenium, biotransformation, salt stress