A research group based at University College Dublin claims it can convert plastics such as polystyrene (PS), polyethylene terephthalate (PET) and mixed plastics into a biodegradable polymer. The team has successfully converted PS to a polyhydroxyalkanoate (PHA) that is flexible, heat stable and water resistant, using the bacterium Pseudomonas putida CA-3. The process involves heat treating the plastic in the absence of air, which breaks the bonds in the plastic and converts it back to the single chemicals that were used to make the polymer in the first place. These chemicals (an oil product in the case of PS and a solid product in the case of PET) are then fed to bacteria, which digest the products fully and, in doing so, start to form a different polymer inside themselves (much like squirrels storing nuts); this polymer is then extracted from the bacteria.
The research group aims to reduce the amount of waste being sent to landfills through a process of biodegradable plastic synthesis that recycles the materials into a new biodegradable product. The process will be of interest to food and drink manufacturers under increasing regulatory pressure to reduce packaging waste and meet EU targets on landfill.