Selective extraction from microalgae Nannochloropsis sp. using different methods of cell disruption

This work studies the extraction of intracellular components from microalgae Nannochloropsis sp. with application of different cell disruption techniques, including pulsed electric field (PEF) (20 kV/cm, 1–4 ms, 13.3–53.1 kJ/kg), high voltage electrical discharge (HVED) (40 kV/cm, 1–4 ms, 13.3–53.1 kJ/kg), ultrasonication (USN) (200 W, 1–8 min, 12–96 kJ/kg), and high pressure homogenization (HPH) (150 MPa, 1–10 passes, 150–1500 kJ/kg). The data evidence that electrically based disruption techniques (PEF and HVED) allowed selective extraction of water soluble ionic components and microelements, small molecular weight organic compounds and water soluble proteins. Microscopic and sedimentation stability analyses have shown that microalgae cells in HVED-treated suspension were noticeably agglomerated and could be easily settled in centrifuge. The electrically based disruption techniques were ineffective for delivery of pigments (e.g., chlorophylls or carotenoids) and their extraction required subsequent application of more potent disruption techniques. The obtained data have shown that HPH disruption technique was the most effective; however, this mode required the highest power consumption.