Integrative combination of gas‒liquid-phase plasma mutagenesis and high-throughput screening to enhance eicosapentaenoic acid production by Schizochytrium sp.

Dietary consumption of eicosapentaenoic acid (EPA) offers diverse health benefits, such as the regulation of blood triglycerides and the prevention of cardiovascular diseases. EPA is naturally synthesized by Schizochytrium sp.; however, its low production level limits its potential for industrial application. The goal of this study was to increase EPA productivity in Schizochytrium sp. by gas‒liquid-phase plasma (GLPP) mutagenesis combined with a high-throughput screening method. First, a diverse array of mutants was generated through GLPP mutagenesis. Next, the mutants with elevated EPA productivity were identified through near-infrared spectroscopy (NIRS). Notably, the M7-25 mutant demonstrated the highest and most consistent EPA production. After the culture medium was optimized, the EPA titer increased from 0.45 to 1.70 g/L. Finally, a cofermentation strategy using ammonia and glucose feeding was employed, and the EPA titer reached 2.08 g/L in a 7-L fermenter. This study reports the highest EPA titer achieved in Schizochytrium sp. via mutagenesis to date, highlighting its great market potential for industrial production.