Revolutionizing Microalgae Harvesting and Cultivation with Living Membranes: A Leap Forward in Optimized Biomass Recovery and Lipid Production

Abstract

A newly designed living membrane filtering module (LMFM) has been applied to promote synergistic cultivation phases and harvesting of Chlorella vulgaris microalgae. The LMFM is based on a living biomembrane intercalated between two woven fabrics made of polyester Dacron that allows an unprecedented simple microalgae recovery from the aqueous cultivation media. A systematic comparison of two systems operated in parallel for biological carbon capture and utilization (bCCU) was executed. The performances of the photobioreactor with a submerged LMFM (membrane photobioreactor, MPBR) were compared to those of a conventional photobioreactor for microalgae cultivation (PBR). PBR and MPBR obtained 92 and 94% carbon dioxide removal yields, respectively. The presence of the membrane did not significantly affect the performance in terms of carbon dioxide removal, which resulted in elimination capacity per stage up to 24.3 ± 4.4 g m^–3 h^–1 in the MPBR. The LMFM indeed afforded a remarkable enhancement in microalgal biomass production and composition in lipids, with lipid concentration up to 36% on dry weight. The produced biomass in the MPBR was almost 80% higher than that obtained in the conventional PBR, and the LMFM allowed an increase of 77% in total lipids. Lipid accumulation was mainly attributed to the increased photon availability in the MPBR. Integrating LMFM in the MPBR enhanced biomass recovery and lipid accumulation, increasing the potentiality of algal-based carbon biofixation as an effective biorefinery technology.