Enhancement of Docosahexaenoic Acid Production by UV Mutagenesis Coupled with Flow Cytometry Screening in Schizochytrium sp. S31

Microalgae have garnered significant attention for their potential in therapeutic and pharmacological applications due to their rich bioactive compounds, including omega-3 fatty acids. Among these, Schizochytrium sp. has been extensively studied for its ability to produce high levels of these valuable lipids. The aim of this study was to create a Schizochytrium sp. S31 mutant library by generating UV-induced random mutations in the genome and then screening for mutants with high lipid accumulation using flow cytometry-based technology. A combination of random mutagenesis and flow cytometry-based selection was employed to isolate high-yield lipid-accumulating mutants of Schizochytrium sp. S31. The results revealed that Mutant 1 exhibited a 28.4% increase in total lipid content, while Mutant 2 demonstrated a 10.8% increase relative to the wild type. The results were corroborated by gas chromatography-mass spectrometry, which indicated that the cultures treated with UV light (for 30 seconds) exhibited higher levels of DHA than the untreated controls. The percentage of DHA increased by 17.9% and 12.1% in two distinct mutants relative to the wild type.