Effect of Titanium Dioxide Nanoparticles on Soil Microbial Population and Antifungal Susceptibility Profile

Titanium dioxide nanoparticles (TiO2 NPs)  are the most widely used nanomaterials which raises concerns about their impacts on soil ecosystems and functioning. The present study evaluated the potential impact of TiO2 nanoparticles applied at different concentrations: 250, 1500 and 9000mg/kg-1 on soil microbial population using standard microbiological methods. Results indicated that the total microbial count were 6.55 + 0.12, 6.59 + 0.23 and 6.55 + 0.12Log10 CFU/g-1 in 250, 1500 and 9000mg/kg-1 of TiO2 NPs amended soil respectively compared to 6.79 + 0.38 Log10 CFU/g-1 in the control. The fungal count were 4.56 + 0.19, 4.77 + 0.23 and 4.90 + 0.12 Log10 CFU/g-1 compared to 3.96 + 0.28Log10 CFU/g-1 in the control. The result reveals that Titanium dioxide nanoparticles exerted a stimulatory effect on fungal abundance and inhibiting effect on bacterial growth. The pprobable organism identified for bacteria belong to the genera Bacillus, Arthrobacter, Agromyces,Sporosacina, Actinomyces, Eubacterium, Listeria, whereas the fungi were Aspergillus, Penicilluim, Fusarium and Rhizopus. Antifungal susceptibility of all the isolates with MAR index of > 0.2 indicates that the presence of  TiO2 NPs in the soil induced resistance to Itraconazole, Fluconazole, Terbinafine and Ketoconazole. The TiO2 NPs exerted concentration dependent, growth stimulatory and antifungal resistance in fungi and inhibited bacterial abundance which potentially can disrupt the ecological balance in the soil.