Phosphorus sustainability: a case for phytic acid as a biorenewable platform

Abstract

Phosphorus (P) compounds play a crucial role in modern society; fertilisers, pesticides and herbicides that maintain global crop outputs and many life-saving pharmaceuticals all contain P. Most P-compounds are sourced from phosphate rock (PR) in a highly energy intensive and redox-inefficient manner. Moreover, the ever-expanding human population has hastened consumption of PR deposits and as peak P use approaches, new technologies that enable alternative, biogenic sources of P to effectively supplement PR are imperative to diversify our global P-platform moving forward. Herein, we propose that phytic acid (PA), a source of biogenic P generally considered a low value agricultural waste-product, could serve as a key platform chemical in future biorefineries. PA possesses several attractive features in this regard; it is relatively non-toxic, highly abundant (∼35 million metric tonnes produced annually by agricultural crops) and exists in the P(V) oxidation state that suggests upcycling could be performed in a redox efficient manner. Finally, it is proposed that if PA were to gain traction as a commodity platform, the flow of P in the form of unabsorbed PA excreted by non-ruminant animals into land and waterways could be significantly reduced.