Exploring the impact of sodium acetate on lipid and carotenoid production in Rhodotorula mucilaginosa

The study employed batch shake flasks to evaluate the impact of various nitrogen sources, phosphate levels, and sodium acetate (Na-acetate) on the Rhodotorula mucilaginosa growth and metabolite production. Adding Na-acetate to the medium resulted in significant improvements in critical metabolites. In shake flask experiments, this led to a cell dry weight (CDW) of 1.65 ± 0.94 g L−1, with lipids comprising 66.53% of the biomass. While β-carotene and carotenoid were 5.84 ± 0.05 and 37.66 ± 2.13 µg g−1, respectively. Subsequent experiments in a batch reactor with Na-acetate supplementation further improved these metrics. CDW increased to 5.02 ± 0.83 g L−1, and lipid content to 65.73 ± 0.81%. Carotenoid production rose to 40.33 ± 1.84 µg g−1, with β-carotene reaching 17.63 ± 0.32 µg g−1. The most promising results were obtained using a fed-batch bioreactor strategy with Na-acetate. R. mucilaginosa achieved the highest yields across all parameters: 48.36 ± 1.14 µg g−1 of total carotenoids, 21.38 ± 1.14 µg g−1 of β-carotene, and a lipid content of 68.58 ± 1.95%.