Omega-3 fatty acids from algae produced biodiesel

Abstract

As the effects of global warming continue to escalate, alternatives to traditional fossil fuels are sought. Biodiesel (FAME – fatty-acid methyl ester) is a promising carbon-neutral fuel produced from photosynthetic organisms such as algae. A novel process by Yadav et al. (2020) for algal oil extraction uses sonic waves and carbon dioxide microbubbles. Although unique, it struggles to compete economically with other processes for biodiesel production. However, a small portion of the FAMEs can be further processed into omega-3 fatty acids, which are nutraceuticals and food supplements, sold at significantly higher prices than biodiesel. Herein, the new algae-to-biodiesel process is augmented to recover valuable FAMEs from biodiesel to produce raw omega-3 fatty-acids. The process utilizes liquid-liquid extraction to remove eicosapentaenoic acid methyl ester (methyl-EPA) and docosahexaenoic acid methyl ester (methyl-DHA) from biodiesel, and uses base-catalyzed, ester hydrolysis to convert the long-chain methyl esters into marketable carboxylic acids. The proposed plant produces 547,830 US-ton of biodiesel per year, satisfying 10% of the current biodiesel market and 12,000 US-ton of omega-3 fatty acids per year. This production level is estimated to be 30% of the U.S. omega-3 fatty-acid market in 2024. Financial analysis of this plant over a 20-year period shows improved profitability depending on the selling price of the omega-3 products and the growth of their market.