Microalgae Harvesting by Self-Driven 3D Microfiltration with Rationally Designed Porous Superabsorbent Polymer (PSAP) Beads

Abstract

Microalgae are emerging as next-generation renewable resources for production of sustainable biofuels and high-value bioproducts. Conventional microalgae harvesting methods including centrifugation, filtration, flocculation, and flotation are limited by intensive energy consumption, high capital cost, long treatment time, or the requirement of chemical addition. In this study, we design and fabricate porous superabsorbent polymer (PSAP) beads for self-driven 3D microfiltration of microalgal cultures. The PSAP beads can swell fast in a microalgal suspension with high water absorption capacity. During this process, microalgal cells are excluded outside the beads and successfully concentrated in the residual medium. After treatment, the beads can be easily separated from the microalgal concentrate and reused after dewatering. In one PSAP treatment, a high concentration factor for microalgal cultures up to 13 times can be achieved in 30 min with a harvesting efficiency higher than 90%. Furthermore, microalgal cultures could be concentrated from 0.2 g L–1 to higher than 120 g L–1 with minimal biomass loss through multistage PSAP treatments. Therefore, the use of PSAP beads for microalgae harvesting is fast, effective, and scalable. It does not require any complex instrument or chemical addition. This technique potentially provides an efficient and feasible alternative to obtain high concentrations of functional biomass at a very low cost.

Virus Stabilization with Enhanced Porous Superabsorbent Polymer (PSAP) Beads for Diagnostics and Surveillance

“…Some of these mechanisms have been verified by our previous studies. For example, PSAP beads with optimal pore structure (pore size < 1 μm) could function as a physical barrier for target species and easily separate undesired impurities (e.g., bacteria, fungi, algae, and protozoa) during sample treatment . In addition, we have observed that protein targets encapsulated in the PSAP beads were not affected by the degrading enzymes of the bacteria Bacillus subtilis, although the enzymes were smaller than the PSAP pore size .…”

“…For example, PSAP beads with optimal pore structure (pore size < 1 μm) could function as a physical barrier for target species and easily separate undesired impurities (e.g., bacteria, fungi, algae, and protozoa) during sample treatment. 23 In addition, we have observed that protein targets encapsulated in the PSAP beads were not affected by the degrading enzymes of the bacteria Bacillus subtilis, although the enzymes were smaller than the PSAP pore size. 24 The results demonstrated that the PSAP beads could not only exclude large impurities but also limit the transport of small impurities in the beads to minimize their impact on the persevered virus targets.…”