Astaxanthin overproduction of Phaffia rhodozyma PR106 under titanium dioxide stress by transcriptomics and metabolic regulation analysis.

In this study, astaxanthin yield of Phaffia rhodozyma PR106 increased significantly under titanium dioxide (TiO2) stress, and the yield of lycopene and β-carotene also increased significantly, as well as the yield of violaxanthin and lutein significantly decreased; in addition, TiO2 stress promoted cell division and changed cell morphology of PR106. Then, the mechanism of increasing astaxanthin yield was studied by transcriptomics and related metabolic regulation. The results showed that astaxanthin accumulation in PR106 was not directly related to mRNA transcription and post-translational modifications regulation under TiO2 stress; TiO2 stress accelerated glucose uptake of yeast, promoted reuse of ethanol, and increased the formation of acetyl-CoA and ATP. The more carbon flux was shifted to astaxanthin synthesis pathway and weakened carotenoids accumulation in astaxanthin branch pathway to improve the astaxanthin production of PR106. The metabolism regulation of ROS could continue in the PR106 strain.