P90: Introduction of new routes and redesign of native pathways for bioplastic production in E. coli

Polyhydroxyalkanoates (PHA) are a class of microbially derived polyesters that are biodegradable, renewable alternatives to traditional, petroleum derived polymers (plastics). While PHA have already shown promise at an industrial scale, their use has been limited in part by cost but also by the physical properties of the polymer (e.g., elasticity). Like all polymers, these properties stem from the make-up of the individual monomer units, such as the length and composition of the side chain as well as the composition of the polymer itself. We have explored the possibility of creating a general approach to producing monomers in vivo from unrelated carbon sources in Escherichia coli via two distinct metabolic pathways. One approach was to exploit the modularity and assembly line characteristics of polyketide synthases (PKS) to generate PHA monomers from basic cellular building blocks. A second approach involved the engineering of native metabolic pathways to produce PHA based on intermediates scavenged from fatty acid metabolism. Genes associated with schemes 1 and 2 were cloned and over-expressed in E. coli and the resulting strains were evaluated for PHA production.