Pulsed Electric Field Treatment of Microalgae for Efficient Biofuel Production

Indianapolis, IN

As energy demand and global warming increase, research has advanced in many types of renewable energies. In particular, biofuels hold special promise for the transportation sector, with bio-ethanol as a success story. However, algae may provide a superior source of biofuels because they store lipids that can be extracted and converted into biodiesel fuel. Compared to sources of bio-ethanol, algae can grow on non-arable lands, have higher fuel production on a mass basis, and create fuel with higher energy density than ethanol. Biodiesel fuel from algae is currently more expensive than conventional fuels. Lipid extraction, usually accomplished with solvents, contributes to the high cost. Extraction efficiency can be enhanced by subjecting the algae suspension to pulsed electric fields (PEFs) as a pretreatment step prior to solvent extraction. This study reports how applying nanosecond and microsecond PEFs with same energy to algae impacts cell viability and lipid extraction. Nanosecond pulses were applied at a fixed pulse duration (60 ns) and electric field (60 kV/cm) in quantities of 10, 50, 100, 200, and 300 pulses. Nanosecond PEFs increased lipid extraction efficiency until 100 pulses, reaching a 19.2% increase in lipid yield. Applying additional pulses had a detrimental effect on lipid extraction. PEF treatment with optimized pulse parameters has potential applications as a pretreatment for large-scale biofuel production.