Polyethylene terephthalate (PET) is a polymer used to make plastic products ranging from synthetic fibers to water bottles. Although PET can be recycled, large amounts of PET end up accumulating in the environment as pollution. A recently discovered bacterium named Ideonella sakaiensis was found to degrade PET by using two enzymes, PETase and MHETase, to break PET into its two constitutive monomers: ethylene glycol (EG) and terephthalic acid (TPA). However, I. sakaiensis’ inability to breakdown PET on a practical time scale undermines its usefulness in eliminating PET pollution. Our project aimed to tackle PET pollution by genetically engineering a synthetic Escherichia coli and Aceintobacter baylyi co-culture to degrade and metabolize PET. We used the following three-pronged approach: (1) engineer E. coli to express and secrete PETase and MHETase for extracellular degradation of PET, (2) engineer E. coli to uptake and metabolize EG, and (3) engineer A. baylyi to uptake and metabolize TPA by expressing foreign TPA utilization genes from Comamonas sp. strain E6. Once individually completed, these three components will then be combined to create a synthetic bacterial co-culture of cooperative E. coli and A. baylyi amino acid auxotrophs. Since both E. coli and A. baylyi are more characterized than I. sakaiensis and also capable of high-throughput mutagenesis, PET degradation and metabolism pathways in an engineered synthetic E. coli and A. baylyi co-culture potentially could be optimized to be even more efficient than those natively found in I. sakaiensis.
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