Pulsed Electric Fields-Based Heterotrophic Auxenochlorella Protothecoides Microalgae Biorefinery Concepts for Food Applications

This thesis investigated the use of pulsed electric fields (PEF) as a controlled and energy-efficient platform for downstream processing of dense heterotrophic microalgae. The results show that PEF treatment combined with incubation increases protein extraction yields while requiring less energy than high-pressure homogenization. During cross-flow microfiltration, PEF-treated suspensions showed higher stable permeate flux and higher protein transmission. These improvements are consistent with lower cake resistance and a particle size distribution that reduces the formation of compact fouling layers. To support scale-up, rheological characterization was combined with multiphysics modeling to define continuous flow operating conditions that promote homogeneous exposure to the electric field. Reversible electropermeabilization windows were identified, and pulse design tradeoffs between extraction performance and cell viability were evaluated. Overall, the thesis supports PEF as a scalable option to improve microalgae downstream processing for food applications.