The Global Crises
Global crises such as freshwater scarcity and plastic pollution are having increased impacts on nature and our lives. One main cause of the exacerbating water scarcity, which renders health and food insecurity, is plastic pollution in water. However, current plastic degradation methods, for example, landfills, are highly ineffective and hazardous while desalination methods, such as reverse osmosis, are costly and difficult to perform in lower-income countries.
Our project, PETZAP, aims to tackle these two global challenges by integrating enzymatic polyethylene terephthalate (PET) degradation into a Microbial Desalination Cell (MDC). The system involves a 3-step process co-culturing engineered E. coli to express a PETase-MHETase fusion degrading PET and P. putida to achieve further degradation and produce lactate, which then supports the biofilm growth of exoelectrogen, S. oneidensis, generating bioelectricity for desalination. Desalination efficiency was maximised by optimising lactate secretion, co-culture design, and MDC configuration based on the results from flux balance analysis (FBA) and agent-based model, simulating bacterial plastic degradation and bioelectricity production, respectively. Insights for further technical optimisation and feasible implementation at large scales were obtained through iterative engagement with experts and stakeholders.