Chen Xiaohong, Liu Lu, Zhu Xingyu, Li Qixuan, Zhao Yuetong, Liu Xiuping, Xie Ningdong, Wang Guangyi
Center of Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China; Research Institute for Marine Traditional Chinese Medicine (Qingdao Academy of Chinese Medical Sciences), Key Laboratory of Marine Traditional Chinese Medicine in Shandong Universities, Shandong University of Traditional Chinese Medicine, Jinan 250355, PR China.
Center of Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China; Graduate School of Shandong Sport University, Jinan 250102, PR China.
Bioresour Technol. 2025 Nov;436:132951. doi: 10.1016/j.biortech.2025.132951. Epub 2025 Jul 8.
Nitrogen sources critically influence cellular growth and lipid biosynthesis in thraustochytrids, yet their effects on docosahexaenoic acid (DHA) production in this heterotrophic marine protist remain unclear. This study examines how ammonium chloride, sodium nitrate, and sodium glutamate regulate DHA and fatty acid biosynthesis in Aurantiochytrium sp. PKU#SW8. Sodium glutamate enhanced glycolysis, tricarboxylic acid (TCA) cycle, nitrogen metabolism, and both fatty acid synthase (FAS) and polyketide synthase (PKS) pathways, yielding higher DHA and fatty acid production than inorganic sources. Ammonium chloride stimulated upstream glycolysis, triacylglycerol (TAG) synthesis and pentose phosphate pathway (PPP) activity, while sodium nitrate promoted fatty acid precursor synthesis, TCA energy generation, and nitrogen metabolism. Combining these nitrogen sources could further improve DHA yield. Enzyme annotations confirmed the presence of a complete nitrogen metabolic network in PKU#SW8. These findings offer valuable insights for optimizing nitrogen sources in microbial DHA fermentation and lipid production.
氮源对破囊壶菌的细胞生长和脂质生物合成有至关重要的影响，然而它们对这种异养海洋原生生物中二十二碳六烯酸（DHA）产量的影响仍不清楚。本研究考察了氯化铵、硝酸钠和谷氨酸钠如何调节橙黄枝霉PKU#SW8中DHA和脂肪酸的生物合成。谷氨酸钠增强了糖酵解、三羧酸（TCA）循环、氮代谢以及脂肪酸合酶（FAS）和聚酮合酶（PKS）途径，与无机氮源相比，其DHA和脂肪酸产量更高。氯化铵刺激了上游糖酵解、三酰甘油（TAG）合成和磷酸戊糖途径（PPP）的活性，而硝酸钠促进了脂肪酸前体合成、TCA能量生成和氮代谢。将这些氮源组合使用可以进一步提高DHA产量。酶注释证实了PKU#SW8中存在完整的氮代谢网络。这些发现为优化微生物DHA发酵和脂质生产中的氮源提供了有价值的见解。
