Metabolomic analysis reveals astaxanthin biosynthesis in heterotrophic microalga Chromochloris zofingiensis

The utilization of gibberellic acid-3, high carbon/nitrogen ratio and salinity concentration can effectively enhance astaxanthin biosynthesis in Chromochloris zofingiensis under the heterotrophic conditions, but the un-derlying mechanisms remained yet to be investigated. The metabolomics analysis revealed that enhancement of the glycolysis, pentose phosphate pathways (PPP), and tricarboxylic acid (TCA) cycle led to astaxanthin accu-mulation under the induction conditions. The increased fatty acids can significantly increase astaxanthin esterification. The addition of appropriate concentrations of glycine (Gly) and gamma-aminobutyric acid (GABA) promoted astaxanthin biosynthesis in C. zofingiensis, as well as benefiting for biomass yield. With the addition of 0.5 mM GABA, the astaxanthin yield increased to 0.35 g center dot L-1, which was 1.97-fold higher than that of the control. This study advanced understanding about astaxanthin biosynthesis in heterotrophic microalga, and provided novel strategies for enhanced astaxanthin production in C. zofingiensis.

Automated summary

The utilization of gibberellic acid-3, high carbon/nitrogen ratio, and salinity concentration can effectively enhance astaxanthin biosynthesis in Chromochloris zofingiensis under heterotrophic conditions. Metabolomics analysis revealed that enhanced glycolysis, pentose phosphate pathways, and tricarboxylic acid cycle led to astaxanthin accumulation. Increased fatty acids also contributed to astaxanthin esterification. The addition of appropriate concentrations of glycine and γ-aminobutyric acid promoted astaxanthin biosynthesis and biomass yield in C. zofingiensis.