Abstract:Thraustochytrids, capable of producing multiple high-value natural active substances, such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), squalene, and carotenoids, have been recognized as an excellent source for commercial lipid production. Firstly, this paper briefed the ecological roles and biotechnological values of thraustochytrids and summarized two biosynthetic pathways of fatty acids. Secondly, we introduced the effects of NaCl, temperature, dissolved oxygen, and pH on the growth, lipid accumulation, fatty acid composition, and DHA production of thraustochytrids. Thirdly, we reviewed the research progress in the strategies for enhancing the DHA biosynthesis ability of thraustochytrids by osmotic regulation, staged fermentation, and alleviating oxidative stress based on environmental stress factors. Finally, we pointed out the existing problems in the current research on the molecular regulation mechanism, staged fermentation strategies, strain improvement, and metabolic engineering of thraustochytrids under environmental stresses, provided solutions for these problems, and prospected the possible development direction in the future. Overall, this review aimed to provide a practical reference for efficient industrial production of DHA by thraustochytrids.
