苹果酸和对氨基苯甲酸复合强化裂殖壶菌S31积累二十二碳六烯酸

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

摘要:

目的 提高二十二碳六烯酸（DHA）的得率。方法 基于裂殖壶菌（Schizochytrium sp.）S31的DHA生物合成途径，系统探究外源添加关键前体物质苹果酸和对氨基苯甲酸对DHA产量的影响。结果 添加苹果酸和对氨基苯甲酸均能够促进裂殖壶菌生产DHA，其最佳添加量分别为4 g/L和0.2 g/L。在此基础上，在5 L搅拌式发酵罐规模下，通过复合添加上述2种物质进一步提高了裂殖壶菌发酵生产DHA的产量。与对照组相比，采用复合添加策略时，DHA生物合成途径中的关键酶活性及葡萄糖消耗速率均显著增强，同时维持代谢能处于4.1×10^-3 g/（g·h）的较低水平。最终，采用复合添加策略后，DHA质量浓度达到7.7 g/L的最高水平，与对照组相比提升了75.0%。结论 作者所提出的苹果酸与对氨基苯甲酸复合添加策略可有效强化裂殖壶菌积累DHA，为其商业化生产提供参考。

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.