Altered lipid accumulation in Nannochloropsis salina CCAP849/3 following EMS and UV induced mutagenesis

• EMS and UV mutagenesis of Nannochloropsis salina combined with FACS for mutant enrichment.
• Productivity of EMS mutants increased by 76% and showed range of FA profile changes.
• Dual EMS and UV mutants accumulated 3 fold more lipid than the wild type.
• Elevation in lipid content comes with a cost to growth rate impacting productivity.
• Mutants suitable for divergent industries generated (biofuel, high value PUFA production).

Microalgae have potential as a chemical feed stock in a range of industrial applications. Nannochloropsis salina was subject to EMS mutagenesis and the highest lipid containing cells selected using fluorescence-activated cell sorting. Assessment of growth, lipid content and fatty acid composition identified mutant strains displaying a range of altered traits including changes in the PUFA content and a total FAME increase of up to 156% that of the wild type strain. Combined with a reduction in growth this demonstrated a productivity increase of up to 76%. Following UV mutagenesis, lipid accumulation of the mutant cultures was elevated to more than 3 fold that of the wild type strain, however reduced growth rates resulted in a reduction in overall productivity. Changes observed are indicative of alterations to the regulation of the omega 6 Kennedy pathway. The importance of these variations in physiology for industrial applications such as biofuel production is discussed.