CAREER: Harnessing the Power of the Phosphate-Binding Protein PstS to Recover Phosphorus

Marquette University, Milwaukee WI

Investigators

Abstract

1554511 Mayer On a global scale, there is an overabundance of waste phosphorus with a simultaneous lack of commercially available phosphorus for use. This contradiction stems from the crucial role of phosphorus for the growth of all biological organisms, plants and animals. As a rate-limiting nutrient, excess phosphorus in the environment is responsible for eutrophication, the leading cause of freshwater impairment. Conversely, phosphorus is vital to global food security as it sustains high agricultural productivity. Worst-case estimates suggest that rapidly diminishing mineable phosphorus reserves could be depleted beyond the realm of economically feasible extraction within a century. In the face of this looming crisis, the recovery of "waste" phosphorus from wastewater and environmental surface waters is no longer a luxury, but an urgent imperative that is the focus of this project. Unfortunately, conventional wastewater treatment is incapable of satisfying new sustainability metrics of capturing phosphorus at low levels and recovering it as a valuable resource. Therefore, the overarching project objective is to elucidate the fundamentals of phosphorus-specific high affinity phosphate-binding protein and evaluate phosphorus removal and recovery efficiency. This is directly relevant to the principal investigator's (PI's) career trajectory as it integrates nutrient recovery, environmental microbiology, sustainability, and STEM education. The pursuit of mutually reinforcing research and educational objectives establishes a strong foundation for the PI's future portfolio of research discoveries and educational advancements. The proposed research will provide the first exploration of phosphorus-specific high affinity phosphate-binding protein in the context of phosphorus sorption and desorption for controlled phosphorus recovery applications. The study will elucidate the fundamental basis of phosphorus-specific high affinity phosphate-binding protein and quantify phosphorus removal and recovery using two protein-based systems: 1) E. coli bacteria engineered to surface-express phosphorus-specific high affinity phosphate-binding protein, and 2) phosphorus-specific high affinity phosphate-binding protein immobilized on synthetic media. Preliminary data indicate that phosphorus-specific high affinity phosphate-binding protein can remove phosphorus, but basic research is needed to improve understanding of the basis of phosphorus-specific high affinity phosphate-binding protein binding and its phosphorus recovery potential. By enhancing the fundamental scientific understanding of phosphorus-specific high affinity phosphate-binding protein capabilities, this project will substantially advance sustainable treatment in the context of the joint criteria of phosphorus removal and recovery. This work is novel in that, for the first time, the potential for controlled phosphorus removal and recovery using immobilized and surface-displayed phosphorus-specific high affinity phosphate-binding protein systems in both water and wastewater will be investigated. The proposed research advances broader societal outcomes, including improved understanding of sustainable technologies; increased minority participation in STEM; and development of a diverse, globally competitive STEM workforce. The results will foster development and evaluation of sustainable biomimicry-inspired technologies for phosphorus recovery. This effort has broader implications for environmental water quality, wastewater infrastructure, mining, global food security, and associated economic and sociopolitical implications.