TiO2 nanoparticles promote the production of unsaturated fatty acids (UFAs) fighting against oxidative stress in Pichia pastoris

Abstract

Since titanium dioxide (TiO₂) nanomaterials are widely implemented in various fields, their safety and toxicity receive detailed investigation. However, their potential effect on living beings, such as oil-producing organisms, has not yet been investigated. In this study, we for the first time investigated the effect of the synthesized anatase TiO₂ nanoparticles on the growth and UFA production of one of the model organisms in the production of unsaturated fatty acids (UFAs), Pichia pastoris. We found that the nanoparticles had low toxicity to this fungus, and this toxicity contributes to cell membrane damage, vacuolar membrane permeabilization (VMP) and cell wall damage-related reactive oxygen species (ROS) accumulation. Interestingly, the synthesized TiO₂ nanoparticles had a positive effect on the production of UFAs to fight against oxidative stress, which is associated with enhancement in lipid droplet (LD) formation and up-regulation of UFA synthesis-related genes. In conclusion, our study emphasizes the positive effect of TiO₂ nanoparticles on the production of UFAs and the potential function of UFAs to alleviate the cytotoxicity of TiO₂ nanoparticles in Pichia pastoris, which contributes to further studies on the toxic mechanism of TiO₂ nanomaterials and the resultant defending pathway of eukaryote cells.