Polyphosphate Accumulation Is Determined by Zinc and Inositol in <i>Saccharomyces cerevisiae</i>

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). P_i starvation and P_i 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 P_i 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 P_i 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.