Algae biodiesel production may be cheaper using electric pulses
Researchers at the Kumamoto University have looked to reduce the costs of biodiesel production using pulsed electric fields (PEF) to extract hydrocarbons from microalgae. Unlike other similar projects, the scientists at Kumamoto have used nanosecond PEF (nsPEF), which requires less energy than PEF. While PEF weakens the cell walls of the algae, nsPEF separates hydrocarbons from a matrix, rather than extracting them from the cell, which ultimately destroys the organism.
In Japan, efforts have been made by researchers to reduce the cost of biodiesel production by using pulsed electric fields (PEF) to extract hydrocarbons from microalgae. A milli- or microsecond PEF is typically used to weaken cell walls and increase permeability allowing for extraction of elements inside the cell. Kumamoto University researchers, on the other hand, used a nanosecond PEF (nsPEF) to focus on the microalgae matrix instead of the cells. A nsPEF generally uses less energy than the μs/msPEFs even at high voltages, and is not as destructive or costly as the traditional drying method of oil extraction.

“The advantage with this extraction mechanism is that it separates hydrocarbons from a matrix, rather than extracts them from cells. Other microalgae do not secrete a matrix so the cell membranes must be damaged or destroyed to get at the hydrocarbons, which both takes more energy and is less efficient than our method,” said lead researcher, Professor Hamid Hosseini of the Institute of Pulsed Power Science at Kumamoto University. “On top of that, many extraction processes practiced today use a drying method to extract oil which ends in the destruction of the algae. Our method is relatively non-destructive and the microalgae are able to rebuild their colonies after extraction has finished.”