Multiple Factors Based Adaptive Laboratory Evolution Strategy Enhances DHA Production in Aurantiochytrium sp. PKU#Mn16 by Rewiring Key Metabolic Pathways

This study developed a high DHA-producing strain of Aurantiochytrium sp. PKU#Mn16 via a multi-factor adaptive laboratory evolution (ALE) strategy combining high dissolved oxygen, low temperature, and citric acid-induced acidity. The evolved strain showed significant increases in biomass (106.3%), total fatty acid yield (243.8%), and DHA yield (171.4%) compared to the wild type. Transcriptomic analysis revealed major metabolic rewiring, including enhanced glycolysis, PKS pathway activity, and energy/redox supply through TCA and PPP pathways. Notably, upregulation of glycerol kinase suggests potential for alternative carbon source utilization. These findings highlight the molecular mechanisms underlying improved lipid biosynthesis and provide a robust foundation for further genetic engineering to optimize fatty acid and DHA production in thraustochytrids.