Transformation of Selenium Nanoparticles by Lactobacillus acidophilus and Biological Activities of Selenium Nanoparticles Produced

Lactic acid bacteria have the ability to reduce sodium selenite to selenium nanoparticles (SeNPs). To obtain SeNPs in a more environmentally friendly way, this study first explored the effects of selenium concentration in the medium, selenium addition time and cultivating duration on the synthesis of SeNPs by Lactobacillus acidophilus, followed by a study of the particle size, zeta potential and antibacterial activity of the SeNPs produced. The results showed that when the selenium content in the medium was 0~600 μg/mL, the higher the selenium concentration was, the more nano-selenium was obtained. When the selenium concentration in the medium was higher than 600 μg/mL, the content of SeNPs in the fermentation broth decreased. The addition of sodium selenite in the early logarithmic stage of bacterial growth was more conducive to the synthesis of SeNPs. After 32 h of culture, SeNPs were almost no longer synthesized. The analysis using scanning electron microscopy and particle size and zeta potential analyzer