Biosynthesis of selenium nanoparticles of Monascus purpureus and their inhibition to Alicyclobacillus acidoterrestris

Alicyclobacillus acidoterrestris is a kind of acid-resistant and heat-resistant gram-positive bacteria which can produce undesirable odors, causing fruit juice spoilage. However, conventional industrial sterilization methods cannot kill this bacterium. Antimicrobial nanoparticles could serve as promising antibacterial agents to inhibit A. acidoterrestris. In this work, selenium nanoparticles (SeNPs) were produced in the fermentation process of a selenium-enriched strain Monascus purpureus 2322 which domesticated in laboratory and their antibacterial activity against A. acidoterrestris was investigated. The as synthesized SeNPs was around spherical with a diameter of approximately 48 nm. Moreover, SeNPs could severely damage the integrity of bacterial cell, resulting in the leakage of cellular contents. Therefore, A. acidoterrestris was inhibited in the presence of SeNPs. These results indicate that the generation of SeNPs by fermentation provides a new efficacious way for developing antibacterial agent against A. acidoterrestris.