Mycogenesis of cerium oxide nanoparticles using Aspergillus niger culture filtrate and their applications for antibacterial and larvicidal activities

Cerium oxide nanoparticles (CeO2 NPs) were synthesized using Aspergillus niger culture filtrate. The mycosynthesized CeO2 NPs were characterized by UV-Visible (UV-Vis), Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Micro Raman, Thermogravimetric/Differential Thermal Analysis (TG/DTA), Photoluminescence, and Transmission Electron Microscopy (TEM) analyses. UV-Vis spectrum exhibited a corresponding absorption peak for CeO2 NPs at 296 nm, and the functional groups present in the fungal filtrate responsible for the synthesis of NPs were analyzed by FT-IR. The further characterization of the mycosynthesized CeO2 NPs revealed particles of the cubic structure and spherical shape, with the particle sizes ranging from 5 to 20 nm. The antibacterial activity of CeO2 NPs was examined in respect of two Gram-positive (G+)bacteria (Streptococcus pneumoniae, Bacillus subtilis) and two Gram-negative (G-) bacteria (Proteus vulgaris, Escherichia coli) by disk diffusion method. The test results for CeO2 NPs at a concentration of 10 mg/mL showed higher activities on the zone of inhibition of up to 10.67 +/- 0.33 and 10.33 +/- 0.33 mm against Streptococcus pneumonia and Bacillus subtilis, respectively, The CeO2 NPs caused 100 % mortality on first instar of Aedes aegypti at 0.250 mg/L concentration after 24-h exposure. The mycosynthesis of CeO2 NPs is a simple, cost-effective and eco-friendly approach and it will also potentially helpful to control pathogenic bacteria and dengue vector.