Evaluating Sustainable Development Pathways for Protein- and Peptide-Based Bioadsorbents for Phosphorus Recovery from Wastewater

Abstract

Recovering phosphate (P) from point sources such as wastewater effluent is a priority in order to alleviate the impacts of eutrophication and implement a circular economy for an increasingly limited resource. Bioadsorbents featuring P-binding proteins and peptides offer exquisite P specificity and sensitivity for achieving ultralow P concentrations, i.e., <100 μg P L −1 , a discharge limit that has been implemented in at least one treatment facility in nine U.S. states. To prioritize research objectives for P recovery in wastewater treatment, we compared the financial and environmental sustainability of protein/peptide bioadsorbents to those of LayneRT anion exchange resin. The baseline scenario (reflecting lab-demonstrated performance at a full-scale implementation) had costs that were 3 orders of magnitude higher than those for typical wastewater treatment. However, scenarios exploring bioadsorbent improvements, including increasing the P-binding capacity per unit volume by using smaller P-selective peptides and nanoparticle base materials and implementing reuse, dramatically decreased median impacts to $1.06 m −3 and 0.001 kg CO 2 equiv m −3 ; these values are in line with current wastewater treatment impacts and lower than the median LayneRT impacts of $4.04 m −3 and 0.19 kg CO 2 equiv m −3 . While the financial viability of capturing low P concentrations is a challenge, incorporating the externalities of environmental impacts may provide a feasible path forward to motivate ultralow P capture.

Phosphate-binding protein-loaded iron oxide particles: adsorption performance for phosphorus removal and recovery from water

“…Selective adsorption and desorption of P i have been documented using several different configurations of immobilized high-affinity phosphate-binding proteins (PBP). [11][12][13][14][15][16][17][18][19] The mechanisms of P i removal by PBP can be explored through molecular dynamics (MD) simulations within an industrial context. For example, MD simulations were used to explore the potential for reagent-less biosensors by combining PBP with rhodamines, which emit fluorescence signals when the PBP is in its unbound conformation.…”

“…23 However, previous PBP research identified the need to enhance the material's adsorption capacity to make PBP a viable alternative for implementation. 12,14,17,18 To increase adsorbent capacity, particles with higher surface area to mass ratios may be used as the base material on which to immobilize PBP, e.g., micro-to nano-scale particles. A range of surfaces can be utilized for biomaterial conjugation (e.g., metals, polymers, or silica).…”

“…23 However, previous PBP research identified the need to enhance the material's adsorption capacity to make PBP a viable alternative for implementation. 12,14,17,18…”