# Polyphosphate Accumulation Is Determined by Zinc and Inositol in Saccharomyces cerevisiae

## TL;DR

This study shows that adding zinc and inositol during phosphate starvation increases polyphosphate production in yeast, offering a sustainable way to make this valuable polymer.

## Contribution

The study identifies zinc and inositol as key drivers of polyphosphate accumulation in S. cerevisiae, linking zinc to the PHO pathway.

## Key findings

- Zinc supplementation activates the PHO pathway to enhance polyphosphate accumulation in yeast.
- Inositol increases polyphosphate hyperaccumulation but its exact mechanism remains unclear.
- Both zinc and inositol improve energy metabolism in S. cerevisiae during phosphate starvation.

## Abstract

Polyphosphate (polyP) is an intriguing polymer with diverse biological and industrial applications. Chemical polyP production is energy‐intensive and limited in chain length at large‐scale production. Alternatively, biological production offers a sustainable solution. Recent research endeavors highlighted Saccharomyces cerevisiae as a promising organism for polyP hyperaccumulation, achieving up to 28% (w/w) polyP (as KPO3). Pi starvation and Pi feeding are essential for this hyperaccumulation phenotype. Prior research demonstrated that trace elements and vitamins increase polyP production in S. cerevisiae when added to the cultivation medium during Pi starvation. However, the role of trace elements and vitamins in enhancing polyP accumulation remained unclear. This study identified inositol and zinc to drive polyP accumulation across various laboratory and industrial S. cerevisiae strains. Moreover, these components influence the energy metabolism of yeasts. Our findings suggest that zinc boosts the phosphate‐responsive signal transduction (PHO) pathway during Pi starvation. The influence of inositol on polyP hyperaccumulation remains elusive, as it does not influence the PHO pathway directly. These findings add to the ever‐growing understanding of polyP metabolism in S. cerevisiae and provide further targets for optimizing biological polyP production.

Zinc and inositol supplementation during phosphate starvation significantly enhances final polyphosphate levels in S. cerevisiae.

Zinc and inositol both increase polyP hyperaccumulation and energy metabolism in Saccharomyces cerevisiae.Effect of zinc and inositol confirmed in laboratory and industrial yeast strains.Zinc directly influences polyP accumulation through PHO pathway activation.The role of inositol in enhanced polyP hyperaccumulation remains elusive.

Zinc and inositol both increase polyP hyperaccumulation and energy metabolism in Saccharomyces cerevisiae.

Effect of zinc and inositol confirmed in laboratory and industrial yeast strains.

Zinc directly influences polyP accumulation through PHO pathway activation.

The role of inositol in enhanced polyP hyperaccumulation remains elusive.