Inhibition of Salmonella typhimurium and Listeria monocytogenes in coconut juice by graphene-doped photocatalyst rGO/TiO2

This research used the photocatalyst rGO/TiO2 prepared by hydrothermal method to inhibit the growth of these microorganisms in water and coconut juice. In coconut juice, the initial count of Salmonella typhimurium decreased from 3 × 105 CFU /mL to 6.3 × 104 CFU /mL, and the initial count of L. monocytogenes was reduced from 3 × 105 CFU/mL to 1.2 × 105 CFU/mL. Moreover, the chemical structure characterization rGO/TiO2 showed that the doping of rGO formed a compact composite, enhanced the transfer of photogenerated electrons, and improved the photocatalytic efficiency of TiO2. The active substances ·OH and ·O2- produced by photocatalysis directly destroyed the integrity of bacteria cells, led to leakage of protein and DNA in the cells, and resulted in inactivation of the microorganisms, although Salmonella typhimurium and Listeria monocytogenes have different cell structures. These results would provide a good candidate photocatalyst to resist Salmonella typhimurium and Listeria monocytogenes and promote the development of photocatalysis applications.

Nitrogen-doped TiO2 microspheres with hierarchical micro/nanostructures and rich dual-phase junctions for enhanced photocatalytic activity

We successfully synthesized microspherical nitrogen-doped TiO₂ with hierarchical nano/microstructures, rich anatase TiO₂–TiO₂(B) phase junctions and a reduced band gap for the photo-degradation of dyes with improved photocatalytic activity.