Enhancement of Docosahexaenoic Acid Production by Schizochytrium sp. S31 via Malic Acid and p-Aminobenzoic Acid Co-feeding

Abstract:

Objective The aim of this study is to improve the yield of docosahexaenoic acid (DHA).Method Based on the synthesis pathway of DHA in Schizochytrium sp., the effects of addition of key precursors, malic acid and p-aminobenzoic acid, on the DHA production was explored.Result The addition of both malic acid and p-aminobenzoic acid enhanced the yield of DHA, and the optimal dosages were 4 g/L and 0.2 g/L, respectively. On this basis, the co-feeding of malic acid and p-aminobenzoic acid was carried out in a 5-L stirred fermenter to further enhance the yield of DHA by Schizochytrium sp. S31. Compared with the control group, the co-feeding strategy enhanced both the activities of the key enzymes in the DHA biosynthetic pathway and the glucose consumption rate, while maintaining the metabolic energy at a low level of 4.1×10^-3 g/(g·h). Finally, when this co-feeding strategy was used, the mass concentration of DHA reached the highest level of 7.7 g/L, which increased by 75.0% compared with that in the control group.Conclusion The proposed co-feeding strategy of malic acid and p-aminobenzoic acid can enhance the accumulation of DHA by Schizochytrium sp. S31, which provides a reference for the commercial production and application of DHA.