The MeY4bioPP project, funded by the German Federal Ministry of Education and Research (FKZ 031B0827B), ran from 1 February 2020 to 30 April 2023 and was carried out jointly by the Institute for Applied Microbiology (iAMB) at RWTH Aachen and Chemische Fabrik Budenheim GmbH. The main objective was to render a previously developed process for polyphosphate (PolyP) hyper‑accumulation in baker’s yeast (Saccharomyces cerevisiae) economically competitive by using rapeseed cake waste as a substrate and by engineering the yeast to produce long‑chain bio‑PolyP (> 60 phosphate units) with high yield per gram of biomass. The project was structured into several work packages. Work package 1 focused on adapting the existing hyper‑accumulation method for high‑throughput screening and on screening a library of 4 500 single‑deletion yeast strains to identify genes that influence PolyP production. The screening platform was successfully transferred to a 96‑well format, allowing rapid growth and PolyP quantification by enzymatic assays. Of the 4 500 strains, 483 were excluded early due to poor growth, and the remaining data set is expected to be fully analysed by the end of 2023. Work package 2 dealt with rational strain engineering. Using CRISPR/Cas9, the polyphosphatases PPN1, PPN2, and PPX1 were deleted, and the vacuolar phosphate exporter PHO91 was removed. Overexpression of the phosphate transporters PHO84 and PHO89, the PolyP‑synthetic complex VTC, and the vacuolar ATPase was introduced. Additionally, the Pho‑regulation pathway was modulated by overexpressing IPK1, IP6K, PHO81, PHO4, and PHO2 to induce a sustained phosphate‑starvation response. The engineered strain CEN.PK113‑7D, a well‑characterised haploid laboratory strain, was used for all manipulations. Functional analysis of single‑gene deletions revealed that removal of PPN1 alone increased PolyP content from 5 % (w/w as KPO₃) to 19 % and extended the average chain length from 10 to 24 phosphate units. Deletions of the other target genes had little or no effect on PolyP accumulation. Combined deletions generally did not further improve yields, indicating that PPN1 is the key limiting factor in this context. The project also attempted global transcription‑machinery engineering (gTME) of the transcription factors PHO4 and PHO2, but this effort was not completed due to time constraints and staffing gaps. The results demonstrate that targeted deletion of PPN1 can substantially enhance PolyP yield and chain length, bringing the process closer to the goal of producing long‑chain bio‑PolyP at industrially relevant scales. The collaboration between iAMB and Chemische Fabrik Budenheim combined academic expertise in metabolic engineering with industrial experience in process scale‑up. The project’s outcomes will inform the subsequent IndYPoP initiative, which plans to screen an industrial yeast collection for further hyper‑accumulating candidates.