Docosahexaenoic acid (C22:6n − 3, DHA) and astaxanthin production by Thraustochytriidae sp. AS4-A1 a native strain with high similitude to Ulkenia sp.: Evaluation of liquid residues from food industry as nutrient sources

Thraustochytriidae sp. AS4-A1, a native strain with high similitude to Ulkenia sp., able to produce docosahexaenoic acid (C22:6n − 3, DHA) and astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione, ASX) was cultivated in growth media based on liquid residues from potato chip processing, and residual mash recovered from a brewery by-product (RB). DHA productivity of these fermentations was compared to productivities of glucose, maltose and starch fermentations. The percentage of DHA in the total fatty acids was between 10.1% and 23.4% depending on growth media composition. RB, as the only source of nutrients, supported growth (8.1 ± 0.4 g/L dry weight biomass) and DHA production (576 ± 40 mg/L); however, its supplementing with yeast extract, monosodium glutamate and B-vitamins (thiamine, biotin and cobalamin) allowed significant increases in DHA productivity (540 mg/L/day), and concentrations of biomass (14.9 ± 0.4 g/L) and DHA (2698 ± 132 mg/L). In all the cases DHA production occurred during the growth period. ASX in the biomass was detected in the late growth rate phase; the highest ASX productivity (63 ± 3 mg/L/day) was obtained in the fermentation of RB as the only source of nutrients.