Toward a circular nitrogen bioeconomy: integrating nitrogen bioconcentration, separations, and high-value products for nitrogen recovery

• Published in: Current opinion in biotechnology 2025-02, Vol.91, p.103225, Article 103225
• Main Authors: Apraku, Edward, Farmer, McKenna, Lavallais, Chayse, Soriano, Danna A, Notestein, Justin, Tyo, Keith, Dunn, Jennifer, Tarpeh, William A, Wells, George F
• Format: Article
• Language: English
• ISSN: 0958-1669; 1879-0429; 1879-0429
• DOI: 10.1016/j.copbio.2024.103225

Recovering nitrogen (N) from wastewater is a potential avenue to reduce reliance on energy-intensive synthetic nitrogen fixation via Haber-Bosch and subsequent treatment of N-laden wastewaters through nitrification–denitrification. However, many technical and economic factors hinder widespread application of N recovery, particularly low N concentrations in municipal wastewater, paucity of high-efficiency separations technologies compatible with biological treatment, and suitable products and markets for recovered N. In this perspective, we contextualize the challenges of N recovery today, propose integrated biological and physicochemical technologies to improve selective and tunable N recovery, and propose an expanded product portfolio for recovered N products beyond fertilizers. We highlight cyanophycin, an N-rich biopolymer produced by a diverse range of bacteria, as a potential target for N bioconcentration and downstream recovery from municipal wastewater. This perspective emphasizes the equal importance of integrated biological systems, physicochemical separations, and market assessment in advancing nitrogen recovery from wastewater. [Display omitted] •Integrated biological-physiochemical processes can improve selective N recovery and expand the product portfolio.•A novel partition-release-recovery (PRR) approach is needed for N recovery.•Cyanophycin, an N-rich biopolymer, is a candidate for N bioconcentration.•A novel PRR approach for N recovery can integrate established physiochemical, biological, and electrochemical techniques.•Recovered N can expand the N portfolio to higher value products outside of fertilizers.