Biosynthesis and characteriсtics of silver nanoparticles obtained using Saccharomyces cerevisiae М437

Abstract

Due to the wide antimicrobial spectrum, silver nanoparticles (AgNPs) have great potential for use in the food industry to control foodborne pathogens. The culture supernatant and cell-free aqueous extract from biomass Saccharomyces cerevisiae M437 were used for the synthesis of AgNPs. The fact of the synthesis of biogenic AgNPs was confirmed by analysing the absorption spectra of the samples in the range of 200-700 nm. The size and zeta potential of AgNPs were determined using Zetasizer Nano ZS. The morphology of nanoparticles was examined using electron microscopy. Using spectral analysis in the UV-visible region, it was confirmed the formation of AgNPs in the investigated solutions. A pronounced absorption peak of AgNPs obtained using a cell-free aqueous extract from S. cerevisiae M437 was recorded in the wavelength range from 300 to 540 nm with a peak at 425 nm. For nanoparticles obtained using the supernatant, a widening spectral range of absorption was observed, which may be associated with the aggregation of AgNPs. AgNPs synthesized using the supernatant S. cerevisiae M437 had a spherical shape with a diameter of about 15 nm. The polydispersity index (PdI) of AgNPs solutions was 0.3, and the zeta potential was 13.6 mV. After storage for 45 days at 4 °C, the PdI value increased 1.6 times, and the zeta potential increased by 11.7 %. This may indicates a possible change in the shape of AgNPs, the formation of an agglomerate, or other processes that takes place in a colloidal solution during storage. AgNPs that were obtained using a cell-free aqueous extract from biomass of S. cerevisiae M437 had an oval shape with a size of 21.3×14.2 nm. The PdI and zeta potential values were similar to the nanoparticles obtained using the supernatant. However, after storage, these values differed significantly: the value of PdI increased 1.3 times, and the zeta potential decreased by 29%. So, the solution of silver nanoparticles obtained in this way is more stable after storage under the specified conditions. The possibility of extracellular synthesis of silver nanoparticles using the yeast Saccharomyces cerevisiae M437 has been shown. The shape, size, and zeta potential of biogenic AgNPs are described and their stability after storage is proved.