Insight in the effect of (a combination of) cell disruption techniques on the extraction of lipids from Nannochloropsis

Microalgae are a promising new type of biomass for the production of food ingredients. Microalgae such as Nannochloropsis sp. are rich in lipids including the essential omega-3 long-chain polyunsaturated fatty acids. Extraction of these lipids while maintaining their stability is not straightforward. In addition, mechanistic insight on the effects of extraction and cell wall disruption techniques on the biomass matrix is often lacking.

This PhD thesis explores the effects of four different cell disruption techniques; high pressure homogenization, ultrasonication assisted extraction, microwave-assisted extraction and enzyme-assisted extraction on the extraction yield and properties of lipids from Nannochloropsis sp.. The latter three extraction techniques will be optimized. After optimization of the individual techniques, combinations of these four different unit operations will be made to find the optimal sequence of unit operations for lipid extraction. The impact of the unit operations on the structural organization of the biomass will be determined using visualization and hyphenated analytical techniques.

The effects of cell disruption and extraction techniques on the lipid stability and composition will be determined by monitoring the fatty acid profile, free fatty acid content, detailed composition of the lipids, the amount of endogenous antioxidants, primary oxidation products and volatile secondary oxidation products. The most interesting extracted oils will be subjected to an accelerated storage test.