DISRUPTION OF Nannochloropsis gaditana (EUSTIGMATOPHYCEAE) RIGID CELL WALL BY NON-THERMAL PLASMA PRIOR TO LIPID EXTRACTION AND ITS EFFECT ON FATTY ACID COMPOSITION

This study assessed the effect of non-thermal plasma (NTP) on Nannochloropsis gaditana cell rupture and subsequent lipid extraction. Micrograph images showed that the surface of original N. gaditana cells appeared smooth and had no apparent holes, whereas after NTP the cells showed a non-uniform apparently fractured surface with many pores and large splits. Maximum lipid recovery from N. gaditana cells (similar to 19%) for NTP-assisted rupture was observed at 10 min, similar to extraction after 10 min sonication (19.0%). The lipid recovery after both pretreatments (average 19.0%) was 2-fold higher than the control treatment (no pretreatment 9.5%). In addition, lipids from unruptured algal cells were mainly composed of omega-3polyunsaturated fatty acids (similar to 31% of total fatty acids), while lipids after NTP were predominantly composed of saturated fatty acids (36.0% of total fatty acids), which could be advantageous for biodiesel production. This study demonstrates an alternative approach based on NTP-technology for algal cell rupture prior to lipid extraction with potential uses for algal biodiesel production.