Mosquito larvicidal activity of synthesized silver nanoparticles from selected bacteria against Aedes aegypti

The present work reports the larvicidal potential of synthesized silver nanoparticles (Ag NPs) using Pseudomonas sp., Bacillus sp. and Lactobacillus sp. which were isolated from soil and milk. The isolated microorganisms were identified by morphological and biochemical tests. The biomass of microorganisms was exposed to 1 mM silver nitrate (AgNO₃) solution for nanoparticle synthesis. The synthesis of Ag NPs was confirmed by visual inspection followed by instrumental analysis such as UV-vis spectroscopy, fourier transform infrared spectroscopy and particle size analyser. Based on the particle size analysis, the size of the Ag NPs were determined to be 52 nm, 137 nm and 95 nm size when synthesized using Pseudomonas sp. Bacillus sp. and Lactobacillus sp. respectively. The biosynthesised Ag NPs exhibited significant larvicidal activity against dengue vector, Aedes aegypti. The LC₅₀, LC₉₀ and X² value of silver nanoparticles from Lactobacillus sp. (8.812 μl/ml, 38.066 μl/ml and 0.478 respectively), Bacillus sp. (0.343 μl/ml, 1.169 μl/ml and X² value 0.160 respectively) and Pseudomonas sp. (0.473 μl/ml, 1.266 μl/ml and X² value 0.253 respectively). The control showed no mortality in the concurrent assay. The study concludes that microorganism mediated synthesized Ag NPs have a potential to control of Ae. aegypti through this eco-friendly and cost-effective approach.