Biosynthesis of silver nanoparticles using native Acetobacter and Pediococcus strains

Among metal nanoparticles, silver due to its high electrical and thermal conductivity and being profoundly anti-bacterial and inexpensive has more importance in comparison with other metals such as gold and platinum. Many acidophilic bacteria can be effective in regenerating many of the nanoparticles due to their metabolism. Experimental samples were collected from Faraman Dairy Factory in Rasht industrial town in May 2019. After isolation and molecular identification to investigate the possibility of biosynthesis of silver nanoparticles, isolates were cultured in liquid medium including Nutrient Broth (NB), Luria- Bertani (LB) and De Man, Rogosa and Sharpe (MRS) to compare their yield. After incubation time for 24 hours, the silver nitrate salt was added separately to supernatant and material that dissolves in liquid. Characteristics of silver nanoparticles determined using Transmission Electron Microscopy, XRD and ultraviolet spectrophotometer (UV-Vis) were investigated. The results gained from the study displayed that the isolated Acetobacter and Pediococcus bacterial strain could produce silver nanoparticles in LB medium. It was also found that the Acetobacter and Pediococcus bacteria could not produce silver nanoparticles in NB and MRS culture media. The study showed that the Acetobacter bacteria in the supernatant phase and the precipitate phase of LB culture medium could produce silver nanoparticles. It was also found that the Acetobacter bacteria could produce silver nanoparticles with sizes of 50 nm and 30 nm. Also, the study showed that the Pediococcus bacteria just in the supernatant phase of LB culture medium could produce silver nanoparticles. It was also found that the Pediococcus bacteria could produce silver nanoparticles with sizes of 100 nm and 50 nm.