Assessment Of Biologically Synthesized Ag Nanoparticles Toxicity Against E. coli, Staphylococcus aureus, Parachlorella kessleri And Sinapis alba

Abstract

In general, Ag⁺ ions and AgNPs are considered to be the most toxic for bacterial cells and less toxic for higher organisms. In the present work inhibitory effects of biologically prepared silver nanoparticles on the growth of bacteria E. coli CCM 3954 and Staphylococcus aureus CCM 3953, green microscopic alga Parachlorella kessleri LARG/1 and seed germination and root growth of plant Sinapis alba seeds were investigated. Surprisingly, silver nanoparticles showed much stronger inhibitory effects on plant seed germination and root growth than on the bacterial growth. At concentration of 75 mg/l AgNPs both seed germination and root growth of Sinapis alba was inhibited whereas inhibition of the growth of E. coli and S. aureus was observed at >195 mg/l. Growth inhibition of alga Parachlorella kessleri was recorded at 300 mg/l AgNPs concentration. The inhibitory effect of silver ions was much higher compared to silver nanoparticles. Even 20 mg/l concentration of Ag⁺ ions inhibited the root growth and concentration > 45 mg/l inhibited germination of Sinapis alba seeds. Inhibition zones in both studied bacteria were found at concentration > 140 mg/l.