Enhanced production of astaxanthin, chlorophyll, and biomass in <i>Haematococcus lacustris</i> (Chlorophyta) using inorganic and organic carbon sources

We investigated the effects of supplementing eight individual carbon sources and four combinations of organic and inorganic carbon sources on the biomass, chlorophyll (chl), and astaxanthin content of Haematococcus lacustris. The findings demonstrated that supplementing nitrogen-free Jaworski’s medium (JM [−N]) with both inorganic and organic carbon sources significantly enhanced the productivities of astaxanthin, chl a and b, and the biomass in H. lacustris. Among the individual supplements tested, NaHCO₃, mannitol, sodium pyruvate, glucose, ethanol, and asparagine notably enhanced astaxanthin production. Sodium bicarbonate, an inorganic carbon source, yielded the highest astaxanthin content among all tested supplements, whereas sodium pyruvate was the most effective among the organic carbon sources. These findings provide a foundation for optimizing carbon supplementation strategies to enhance pigment and biomass production during H. lacustris cultivation, thereby contributing to the potential commercial viability of astaxanthin production.