Microalgal feedstock for the production of omega-3 fatty acid ethyl esters and ɛ-polylysine

Microalgal omega-3 fatty acids are considered as an efficient alternative for fish-based omega-3 fatty acids. Ethyl esters derived from omega-3 fatty acids are being considered as the drug for hypertriglyceridemia. In this study, omega-3 fatty acids rich Chlorella sp. was utilized for the transesterification for the ethyl ester production using a potassium carbonate alkaline catalyst. At the optimized conditions of transesterification, 86.2% ethyl ester yield was achieved with solvent to algae ratio (20 mL/g), water addition (45 %), catalyst (4 %), temperature (75°C), and reaction time (60 min). Additionally, the acid-hydrolysed spent biomass was used for the production of ɛ-polylysine by fermentation using Streptomyces sp. as fermentative organism. The maximum yield of 1.78 g/L was achieved after 90 h fermentation. This study established a biorefinery approach where two highly valuable compounds could be produced from the Chlorella sp. by transesterification followed by fermentation.