Bio-mediated synthesis of TiO2 nanoparticles and its photocatalytic effect on aquatic biofilm

The nano-TiO2 was synthesized biologically employing Bacillus subtilis (FJ460362). These nanoparticles were characterized by FTIR, TGA–DTA, UV–Visible spectroscopy, XRD and TEM. FTIR and TGA results confirm that the organic impurities were completely removed while calcinating the resultant products. Band gap value was estimated from the UV–Visible spectrum and anatase crystal phase was confirmed by XRD. TEM images reveal that these particles were agglomerated; mostly spherical in shape with an average particle size of 10–30 nm. The synthesized nano-TiO2 particles were coated on glass slides, biofilm were grown and subjected to irradiation of polychromatic light to understand photocatalytic activity in controlling the aquatic biofilm. The bacterial killing process was established by Epi-fluorescence microscopy. The results reveal that biogenic TiO2 nanomaterial acts as good photocatalyst by the generation of H2O2 in the vicinity of the TiO2-biofilm interfaces to suppress the growth of the aquatic biofilm.