Abstract:The preparation of selenium nanoparticles from microorganism had low toxicity, mild synthesis and other advantages, showing broad application prospects. A strain which could reduce sodium selenite to selenium nanoparticles was isolated and purified from the soil with supplemental selenium fertilizer in Wuhan. The strain was identified, and its selenium tolerance and growth kinetics curve were determined. The selenium nanoparticles were characterized by scanning electron microscope, and the inhibitory activity of selenium nanoparticles and the secondary metabolites on α-glucosidase were preliminarily explored. The results showed that among the 16 strains isolated and purified, the maximum tolerance concentration of Cytobacillus firmus N4 to sodium selenite was 36 mg/mL with the selenium nanoparticle size of 150~220 nm. When the concentration of selenium nanoparticles was 0.625 mg/mL, the inhibition rate of α-glucosidase was 25.42%±0.69%, and the inhibition rate reached to 73.83%±4.63% when the concentration of secondary metabolites was 2.500 mg/mL. Cytobacillus firmus N4 has high selenite-tolerance, providing the basis for the biotransformation of selenium nanoparticles, and its secondary metabolites show certain α-glucosidase inhibitory activity, which is worthy of further study.
