Biosynthesis of Magnesium Oxide Nanoparticles by E. hirae isolated from traditional yogurt in Rafsanjan, Iran.

There is a lot of evidence about the beneficial biological effects of probiotics in food and dairy products. Antimicrobial properties, ability to produce biosurfactant and biosynthesis of nanoparticles are among the significant effects of these organisms. The aim of this research is the biosynthesis of magnesium oxide nanoparticles by Enterococcus hirai from traditional yogurt. MRS agar culture medium was used to isolate probiotics. Biosurfactant-producing isolates were examined in terms of hemolysis, crude Oil Spreading Assay, Drop Collapse Assay and emulsification index, the best isolate for the production of magnesium oxide nanoparticles, size, antioxidant activity, FTIR and antibacterial effects were evaluated and identified by PCR. 9 isolates had probiotic properties, isolate L11 was selected with higher biosurfactant production ability. The antibacterial property of the produced biosurfactant was shown against Gram-positive and Gram-negative bacteria. This strain was also able to produce magnesium oxide nanoparticles. The formed nanoparticles with a size of 135 nm showed significant antibacterial and antioxidant effects. The best strain was introduced as Enterococcus hirai. According to the findings, it seems that this probiotic strain producing biosurfactant and magnesium oxide nanoparticles can be used in food and industrial industries.