(164a) A Polyketide Synthase-Based Platform for Making Plastic Monomers of Polydiketoenamines

Plastics in use today are predominantly single-use and rarely recycled. The linearity of their life cycles is not only wasteful from a resource and energy perspective, it has also resulted in environmental stresses with >6 billion metric tons of plastic waste. This study provides a platform to biologically produce a specific type of lactones, the important molecules for synthesis of a new class of dynamic covalent polymer networks, known as vitrimers, which combine the processing and recycling ease of thermoplastics with the performance advantages of thermosets. Regarding circularity, most vitrimers are differentiated from classical thermosets in that they can be chemically de-polymerized, typically into small molecules or short oligomers, including lactones and diacids. For decades, microbial production of commodity chemicals is limited in the diversity of the molecules produced by natural or modified enzymes. Our technology of recombining the Type I polyketide synthases (PKSs) and other enzymes demonstrates a promising strategy for the synthesis of diversified lactones for making a variety of vitrimers with different properties.