Mechanical cell disruption for lipid extraction from microalgal biomass

Cell disruption is an integral part of the downstream operation required to produce biodiesel from microalgae. This study investigated the use of ultrasonication and high-pressure homogenization (HPH) as cell disruption methods for two microalgal species, Tetraselmis suecica (TS) and Chlorococcum sp. (C sp.). The kinetics of cell disruption followed a first-order model (0.65 < R2 < 1.00). Disruption rate constant for ultrasonication was directly proportional to power level and followed a parabolic relationship with initial cell concentration, while that for HPH was directly proportional to operating pressure and inversely proportional to initial cell concentration. Mean disruption rate constant for HPH was approximately seven times that for ultrasonication. Mean disruption rate constant for TS cells was roughly 20% higher than that for C sp. cells. Subjecting TS culture to cell disruption prior to lipid extraction resulted in 5–8-fold increase in lipid yield and 3–5-fold increase in triglyceride yield.