Synthesis of silver nanoparticles stabilized by the products of mechanically assisted hydrolysis of yeast biopolymers

Abstract

The paper presents data on the production of silver nanoparticles and their stabilization by products of the mechanoenzymatic hydrolysis of yeast biomass. The formation of silver nanoparticles by reduction using glucose without the addition of stabilizers was studied. The particles obtained have a spherical shape and a narrow size distribution. The resulting colloid is unstable and precipitates after 3-5 hours due to aggregation of unstabilized particles. Polymers contained in yeast hydrolyzates were selected taking into account silver particles nucleation mechanism. The protein molecules of these hydrolysates are involved in the formation of salts and the stabilization of the resulting dendrites. Low-molecular carbohydrates play the role of a reducing reagent. The peak on the Vis spectrum at 420 nm attributed to particles with dimensions of about 50 nm gives evidence that these dendritic formations are nanostructured. It was shown that mechanical activation together with enzymatic hydrolysis promotes an increase in the concentration of carbonyl groups of carbohydrates leading to an increase in the regenerating ability of the cell wall. The varying the processing conditions one can get silver particles in the range of 15-80 nm. Changes in silver reduction in the liquid phase in the presence of cell hydrolysis products were detected. Part of the carbohydrates as a result of hydrolysis becomes water soluble and is extracted into the solution. This leads to the fact that in the extracellular space also undergo reduction processes. In general, samples of the mechanically processed and hydrolyzed enzyme product have a greater reducing ability compared with the original cells. The quantity of spatially stabilized nanoparticles is larger than when processing native S. cerevisiae cells.