(642g) Towards One-Pot Conversion of Polyester Mixtures Using Biocompatible Aqueous Ionic Liquid

Plastics commingled in municipal waste streams makes sorting and recycling very challenging, posing a dire threat to ecosystems and human health. The increasing popularity of polylactic acid (PLA) presents a risk of cross-contamination in the recycling of polyethylene terephthalate (PET). This study demonstrates the feasibility of applying ionic liquids (ILs) in depolymerization of PET and PLA mixtures. Over 95% of theoretical monomer yields were achieved using cholinium lysinate ([Ch][Lys]) in water. This observation agreed with the results of molecular dynamic simulation, where [Ch][Lys] was found to have better polymer dissolution over other studied ILs. Pseudomonas putida can utilize IL-depolymerized PET/PLA mixture as the carbon sources for cell growth without additional feed of glucose. When the depolymerized plastics are converted to polyhydroxyalkanoates (PHA) using an engineered P. putida in a one-pot process configuration, the optimal production cost and carbon footprint of PHA are estimated to be significantly lower than sugar-derived PHA. This integration of polymer hydrolysis and biological valorization underscores the potential for ILs to enable one-pot upcycling of mixed plastic wastes.