Two-stage cyanophycin bioprocesses through thermal control of E. coli metabolism

• Applicant: Professor Dr.-Ing. Hannes Link
• Subject Area: Biological Process Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563766578

This project addresses the challenge of producing bioplastics, specifically cyanophycin, through effective and sustainable bioprocesses. Cyanophycin is a polymer that consists of the amino acids aspartate and arginine, and has a high potential for various industrial and biomedical applications. However, current cyanophycin production processes suffer from limited efficiency and high costs, because they require sugar-based feedstocks or external supply of amino acids. The goal of this project is to develop a two-stage bioprocess using engineered Escherichia coli, where growth and cyanophycin production are fully decoupled. We hypothesize that growth decoupling will enable processes with sustainable substrates like ethanol, which hardly support growth and production in conventional processes. To achieve this, we will use temperature-sensitive (TS) mutations as thermo-switches, which we used in previous work for precise control over microbial growth and metabolic activity. These thermo-switches will allow us to engineer E. coli strains that transition between two optimized states: one for producing high levels of metabolically active biomass and another for cyanophycin production. In the production state, amino acid pathways will be engineered to optimize the internal supply of arginine and aspartate, which has the potential to improve cyanophycin synthesis. Downstream processing improvements will include testing thermo-switches in cell wall metabolism to induce cell lysis at higher temperatures, which may enable solvent-free extraction of cyanophycin. By decoupling growth and production phases and optimizing monomer supply, the project aims to enhance the economic viability and sustainability of cyanophycin production, contributing to the broader goal of advancing bio-based plastics.

• DFG Programme: Research Grants