Applications of pulsed electric field treatment in downstream processing of microalgae biomass

In recent years, many studies have shown that the use of pulsed electric field (PEF) technology to extract valuable compounds from microalgae is suitable for energetic and nutritional purposes and meets economic requirements. This was only possible through the implementation of the microalgae biorefinery concept, which involves the use of the residual biomass after the extraction of high and medium value products for biofuel production. A major advantage of PEF treatment is the bypassing of drying and the immediate processing of the wet concentrated biomass. Moreover, PEF treatment can be used as a mild and effective method of cell disruption, facilitating recovery of unaltered constituents at low energy costs and allows cascade processing for multiple component recovery, since it does not destroy cell shape and maintains gravimetrical biomass separability after single extraction step. It was shown that efficient protein extraction after PEF treatment requires an incubation step, and that the progress and kinetics depend on the biomass concentration and the incubation conditions. In addition to diffusion in a chemical gradient, a second biological, enzymatically driven process within the PEF-treated biomass was confirmed to facilitate the release of proteins from the cells. ... mehrIn a next processing step, the lipid fraction was recovered with an efficiency higher than 90%, demonstrating that PEF processing satisfy the demand for a low energy-consuming technology for cascade valorization of microalgae biomass. Although the integration of PEF technology into the biorefinery concept is possible and has been demonstrated at laboratory scale, there are no large-scale trials on downstream processing of microalgae biomass. This chapter also discusses factors affecting the implementation of PEF technology in biorefineries, including upscaling from laboratory to outdoor cultivation and the subsequent downstream process involving PEF treatment as a first step to industrial scale.