Programmable balancing of growth and formation of poyhydroxyalkanoates in Escherichia coli

Abstract

The replacement of petrochemical products such as plastics by renewable, bio-based substitutes is a first-order priority in the technological agendas of our countries. For a successful transition, efficient design-based cell factories are required. While decades of research have increased our knowledge in metabolic network function, the quantitative understanding of the regulatory mechanisms is still far from being complete. With this project, we intend to develop quantitative models to design a 'programmable' balancing between growth and product formation. Using as a case study the production of a bio-plastic (polyhydroxyalkanoate) in Escherichia coli, we want to address the following questions: Which metabolites from central carbon metabolism are the signals that determine the growth rate? Can we reprogram the allocation of cellular resourcesbetween the generation of a product of interest and biomass formation by altering these signals andjor altering the signaling routes? To identify and study the roles of these "signaling metabolites" in the interaction between the metabolic and regulatory networks, we will manipulate the nature and availability of the nutrients and we will change the net stoichiometry of the glycolysis. To get insight into the systemic changes after the proposed manipulations, we will obtain quantitative data on the growth rates, the metabolic fluxes, transcriptional changes, proteomic profiles and concentrations of intracellular metabolites. We intend to develop a comprehensive model able to describe the observed changes and predict the outcome of similar metabolic interventions. With the collaboration between our laboratories at the Delft University of Technology and the University of Sao Paulo, we will have a multidisciplinary team with expertise in molecular biology, polyhydroxyalkanoate synthesis, quantitative proteomics and metabolomics, fluxomics and metabolic modeling. To exchange knowledge and divulge our results, we plan a joint advanced course in Brazil entitled 'Microbial Systems Biology'; half-yearly meetings, and an open workshop at the end of this project. (AU)