Effects of the biogenic gold nanoparticles on microbial community structure and activities

This study reports the terrestrial ecotoxicity of the spherical gold nanoparticles with size of 14 +/- 3 nm and the negative surface charge of -33 +/- 3 mV synthesized by the biomass of Streptomyces rimosus. The impact of these gold nanoparticles on the size and structure of microbial communities in the garden soil was analyzed by the enumeration of culturable soil microorganisms and community level physiological profiles (CLPP). Treatment effects on soil enzymatic activities for beta-glucosidase, urease, alkaline phosphatase, and dehydrogenase were followed. Toxicity towards soil microorganisms involved in carbon and nitrogen transformation was determined. The data obtained in this study demonstrate that the biogenic gold nanoparticles up to the concentration of 33 mg kg (-1) do not affect the soil processes and can be classified as not harmful..