New processes convert waste PS and PET to biodegradable polymers, recycles PET for use in food packaging

University of Dublin has developed an interesting method of converting synthetic polymers such as polystyrene (PS) to PHA, a biodegradable polymer. The team successfully converted PS to a polyhydroxyalkanoate (PHA) that is flexible, heat stable and water resistant, using the bacterium Pseudomonas putida CA-3. The process will be of interest to food and drink manufacturers under increasing regulatory pressure to reduce packaging waste and meet EU targets on landfills. The research group has applied for patents in relation to the conversion of PET and mixed plastic using the technology and it is hoping to form partnerships with waste and packaging companies to commercialize the project.
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.

A new waterless process for recycling of PET flakes has been developed by US based ECO2 Plastics located in California in USA. ECO2 has developed a process based on bio solvent approved by US FDA instead of water, and reduces contaminants less than 0.5 PPB (Part Per Billion), the threshold set by the US food safety agency.
The first application of recycled PET is expected to be in ready prepared food products that will be heated again at temperatures exceeding 121�C. The regulatory approval enables the company supply packaging producers with recycled PET that is of purity suitable for use of up to 100% recycled content of the packaging for ready-prepared foods that will be reheated in their container at temperatures exceeding 121�C or stored in a refrigerator or freezer. Unlike other recyclers, EC02�s process eliminates the use of water for the cleaning of plastics through the use of a bio solvent that is FDA approved for use as a food additive in conjunction with liquid CO2� a by product of power plant emissions � in a closed loop system that pours nothing down the drain.
US food processors are also beginning to initiate recycling collection networks around PET packaging for food to increase the amount of feedstock that is available to produce RPET. A recent study by UK-based market analysts Applied Market Information (AMI) earlier this year, claims that the market for bioplastics remains small, not least because of a lack of facilities to ensure that the packaging can be recycled or composted properly. Less than 1% of global polymers are currently classified as compostable bioplastics according to the European EN 13432 standard. Plastics have to completely biodegrade into harmless microscopic fragments within 90 days. However, the standard allows for this to take place within ideal composting conditions, such as industrial composting facilities where the materials are heated to high temperatures in order to accelerate the composting process.