Phycobiliprotein recovery coupled to the tertiary treatment of wastewater in semi-continuous photobioreactors. Tracking contaminants of emerging concern.

Abstract

This study evaluated a tertiary wastewater treatment technology using cyanobacteria to recover value-added phycobiliproteins. The presence of contaminants of emerging concern (CECs) in wastewater, cyanobacterial biomass and pigments recovered were also analyzed. For this, a wastewater-borne cyanobacterium (Synechocystis sp. R2020) was used to treat secondary effluent from a municipal wastewater treatment plant, with and without nutrients supplementation. Then, the stability of phycobiliprotein production was assessed by operating the photobioreactor in semicontinuous mode. Results showed similar biomass productivity with and without nutrients supplementation (153.5 and 146.7 mg L?? 1 d?? 1, respectively). Upon semi-continuous operation, the phycobiliprotein content was stable and reached up to 74.7 mg gDW?? 1. The phycocyanin purity ratio ranged from 0.5 to 0.8, corresponding to food grade (>0.7). Out of 22 CECs detected in secondary effluent, only 3 were present in the phycobiliprotein extracts. In order to identify applications, prospective research should focus on CECs removal during pigment purification.