Print Email Facebook Twitter Operational Strategies to Selectively Produce Purple Bacteria for Microbial Protein in Raceway Reactors Title Operational Strategies to Selectively Produce Purple Bacteria for Microbial Protein in Raceway Reactors Author Alloul, A. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen) Cerruti, M. (TU Delft BT/Environmental Biotechnology) Adamczyk, Damian (Universiteit Antwerpen) Weissbrodt, D.G. (TU Delft BT/Environmental Biotechnology) Vlaeminck, Siegfried E. (Universiteit Antwerpen) Date 2021 Abstract Purple non-sulfur bacteria (PNSB) show potential for microbial protein production on wastewater as animal feed. They offer good selectivity (i.e., low microbial diversity and high abundance of one species) when grown anaerobically in the light. However, the cost of closed anaerobic photobioreactors is prohibitive for protein production. Although open raceway reactors are cheaper, their feasibility to selectively grow PNSB is thus far unexplored. This study developed operational strategies to boost PNSB abundance in the biomass of a raceway reactor fed with volatile fatty acids. For a flask reactor run at a 2 day sludge retention time (SRT), matching the chemical oxygen demand (COD) loading rate to the removal rate in the light period prevented substrate availability during the dark period and increased the PNSB abundance from 50-67 to 88-94%. A raceway reactor run at a 2 day SRT showed an increased PNSB abundance from 14 to 56% when oxygen supply was reduced (no stirring at night). The best performance was achieved at the highest surface-to-volume ratio (10 m2 m-3 increased light availability) showing productivities up to 0.2 g protein L-1 day-1 and a PNSB abundance of 78%. This study pioneered in PNSB-based microbial protein production in raceway reactors, yielding high selectivity while avoiding the combined availability of oxygen, COD, and darkness. Subject alternative protein sourceanaerobic fermentationcarboxylate platformhigh-rate algae pondnutrient recoverypurple phototrophic bacteriashort-chain fatty acidsingle-cell protein To reference this document use: http://resolver.tudelft.nl/uuid:bca47ea5-bb36-49c6-8225-36d4081e70fc DOI https://doi.org/10.1021/acs.est.0c08204 Embargo date 2022-06-04 ISSN 0013-936X Source Environmental Science & Technology (Washington), 55 (12), 8278-8286 Bibliographical note Accepted Author Manuscript Part of collection Institutional Repository Document type journal article Rights © 2021 A. Alloul, M. Cerruti, Damian Adamczyk, D.G. Weissbrodt, Siegfried E. Vlaeminck Files PDF ManuscriptESTAbbasAlloul.pdf 1.6 MB Close viewer /islandora/object/uuid:bca47ea5-bb36-49c6-8225-36d4081e70fc/datastream/OBJ/view