Astaxanthin overproduction and proteomic analysis of Phaffia rhodozyma under the oxidative stress induced by TiO2.

This study analyzed the effect of TiO2 on the growth and astaxanthin yield of P. rhodozyma PR106. Subsequently, proteomics method was used to analyze the proteins changes of the strain under TiO2 treatment, to investigate the metabolic mechanism of the active oxygen generator TiO2 promoting the astaxanthin synthesis in P. rhodozyma. The results showed that TiO2 caused oxidative stress response in P. rhodozyma, and astaxanthin yield was 14.74 mg/L, which was 2 times of the control group; while, TiO2 had no effect on biomass and apoptosis of the cells. Proteomics analysis and parallel reaction monitoring (PRM) technology initially explored that bud-site selection protein (BUD22), ubiquitin-40s ribosomal protein s31 fusion protein, cell cycle control protein, C-4 methyl sterol oxidase and glutaredoxin were associated with astaxanthin synthesis.