Pea whey wastewater as a medium additive for the production of docosahexaenoic acid (C22:6 n3).

In this study, the potential of pea whey wastewater (PWW) as a substrate for the biosynthesis of docosahexaenoic acid (DHA) was investigated by culturing the strain Aurantiochytrium limacinum SFD-1502. The results showed that culturing SFD-1502 in PWW alone resulted in poor growth, possibly due to an insufficient carbon source. The addition of glucose and monosodium glutamate to PWW resulted in a significant improvement in cell growth, and the dry weight of the cells reaching 43.45 ± 0.39 g/L g/L, comparable to that of the control (using artificial seawater fermentation medium), despite the lipid content in the cells and the DHA proportion in the lipids were slightly lower than those of the control. Subsequent studies demonstrated that the presence of raffinose family oligosaccharides, a higher concentration of arginine, and a lower concentration of Na⁺ relative to artificial seawater in PWW resulted in the reduction of cellular lipids and the proportion of DHA. Furthermore, the chemical oxygen demand (COD) of PWW was reduced by approximately 60% during the fermentation. Consequently, the utilization of PWW in A. limacinum culture for DHA production is a viable and cost-effective strategy.