Effect of combined pulsed electric energy and high pressure homogenization on selective and energy efficient extraction of bio-molecules from microalga Parachlorella kessleri

Abstract

This work investigates the potential of pulsed electric energy (pulsed electric fields (PEF) and high-voltage electrical discharges (HVED)) and high pressure homogenization (HPH) for extraction of bio-molecules from Parachlorealla kessleri. The applied procedures included individual pulsed electric energy (PEF, HVED), HPH treatments, and their combination. The cell concentrations of suspension applied in PEF or HVED treatment were 5–25 g/L, while 5 g/L suspension was always applied for HPH treatment. The effects of applied procedures on the extraction of ionic components, carbohydrates, proteins, and pigments were evaluated. The data evidenced that HVED treatment allowed selective extraction of ionic components and carbohydrates, while HPH treatment was most efficient for simultaneous release all the bio-molecules. HPH treatment (120 MPa, 10 passes) gave 4-fold higher content for pigments, 1.2-fold higher content for carbohydrates and 6.5-fold higher content for proteins than HVED treatment (40 kV/cm, 8 ms). For combined procedure, application of preliminary PEF or HVED treatment with 5 g/L suspension allowed increasing the extraction of carbohydrates at high energy consumption. By contrast, application of preliminary HVED treatment with 15 g/L or 25 g/L suspensions allowed enhancing extraction efficiencies of carbohydrates and proteins, and reducing total energy consumption.