Biotechnological polyphosphate as an opportunity to contribute to the circularization of the phosphate economy.

Polyphosphates, chains of polymerized phosphate subunits, are used as food additives for various applications such as conservation, water retention, and pH buffering. Currently, the value chain of phosphates is linear, based on mining fossil phosphate rock, which is anticipated to be depleted in a few hundred years. With no replacement available, a transition to a circular phosphate economy, to which biological systems can contribute, is required. Baker's yeast can hyperaccumulate phosphate from various phosphate-rich waste streams and form polyphosphates, which can be used directly or as polyphosphate-rich yeast extract with enhanced properties in the food industry. By maturing the technology to an industrial level and allowing upcycled waste streams for food applications, substantial contributions to a sustainable phosphate economy can be achieved.