Exposure of Metal Oxide Nanoparticles on the Bioluminescence Process of P and P Recombinant P. putida mt-2 Strains

Comparison of the effects of metal oxide nanoparticles (NPs; CuO, NiO, ZnO, TiO₂, and Al₂O₃) on different bioluminescence processes was evaluated using two recombinant (P and P) strains of Pseudomonas putida mt-2 with same inducer exposure. Different sensitivities and responses were observed according to the type of NPs and recombinant strains. EC₅₀ values were determined. The negative effects on the bioluminescence activity of the P strain was greater than for the P strains for all NPs tested. EC₅₀ values for the P strain were 1.7- to 6.2-fold lower (corresponding to high inhibition) than for P. ZnO NP caused the greatest inhibition among the tested NPs in both strains, showing approximately 11 times less EC_50s of CuO, which appeared as the least inhibited. Although NPs showed different sensitivities depending on the bioluminescence process, similar orders of EC_50s for both strains were observed as follows: ZnO > NiO, Al₂O₃ > TiO₂ > CuO. More detailed in-depth systematic approaches, including in the field of molecular mechanisms, is needed to evaluate the accurate effect mechanisms involved in both bioluminescence metabolic processes.