Pulsed electric fields applied to the control of predators in production scale microalgae cultures

A 2.7 m
³
microalgae photobioreactor culture was treated with Pulsed Electric Fields, PEF, for 6 hours with 1.25 kV/cm, 65 μs pulses of 50 Hz. Working with recirculation, all the culture was uniformly exposed to the PEFs throughout the assay. The development of the microalgae and protozoan populations was followed and the results showed that PEF is effective on the selective elimination of protozoa from microalgae cultures, inflicting on the protozoa growth halt, death or cell rupture, without affecting microalgae productivity. Specifically, the results show a reduction of the active protozoa population of 87% after 6 hours treatment and 100% after few days of normal cultivation regime. At the same time, microalgae growth rate remained unaffected.