The extensive use of plastics in recent decades has led to an increasing amount of plastic wastes which consists of non-biodegradable and non-incinerable plastics such as polyethylene terephthalate (PET) and polyurethane (PU). These wastes are discarded into the environment causing serious environmental pollution problems. This has inspired our team to search for effective scientific options to help reduce plastic pollution. In this project, we have adopted an in-silico mutagenesis approach to design two PU-degrading enzymes - papain and polyurethanase esterase A (PueA) - that could be used to enhance PET and PU biodegradation. Ultimately, we are aiming to construct a multi plastic-degrading E. coli bug by combining the genes of the two mutant enzymes (papain and PueA) with the well-studied polyethylene terephthalate hydrolase (PETase) gene in a single biobrick. It is hoped that this technology will contribute to reducing plastic wastes and help better protect our environment.