Microalgae as a Source of Functional PUFAs: A Green Low-cost Pathway via Enzymatic Hydrolysis

Abstract

Microalgal oil is an alternative source of polyunsaturated fatty acids (PUFAs) that can replace conventional ones such as vegetable and fish oils. In this work, Nannochloropsis gaditana oil was investigated as a source of high-value polyunsaturated fatty acids. The cultivation conditions were optimized using a 22 full factorial design to simultaneously assess the influence of NaNO3 (0.075 to 0.225 mg.L-1) and CH3COONa (2 to 6 g.L-1) concentrations on the lipid productivity. All cultivations were done in 4 L tank photo bioreactors for 7 days, yielding 21.87 mg.L-1.day-1 maximum lipid productivity when using 225 mg.L-1 of nitrate and 6 g.L-1 of acetate. The obtained microbial oil was further characterized revealing palmitic (22.1%), oleic (22.3%), and linoleic (17.0%) as the main fatty acids. The resulting microbial oil was employed in the hydrolysis reactions and different sources of lipases as biocatalysts. The highest performance was achieved by the lipases Burkholderia cepacia (86%), Candida rugosa (84%), and Rhizopus oryzae (82%).