VATIS UPDATE Article

A group of Japanese researchers from the Kyoto Institute of Technology and Keio University, have discovered a species of bacteria that degrades and assimilates poly ethylene terephthalate (PET) commonly used for water bottles. The team gathered 250 samples of PET contaminated by sediment, soil and wastewater from a plastic bottle recycling site. The researchers screened the microbes living on the samples to identify whether any were using the PET as a growth source.

While they found a number of microbes broke down the PET film, one newly discovered bacteria species, Ideonella sakaiensis 201-F6, was responsible for converting 75% of the PET carbon into carbon dioxide (CO2). The scientists explained, “By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, which is able to use PET as its major energy and carbon source.” The bacterium was able to almost completely degrade a thin film of PET after six weeks at 30°C.

When grown on PET, the bacterium produces two enzymes capable of hydrolysing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. The bacteria then digest both substances. The two enzymes – PETase and MHETase – efficiently break down PET into its two environmentally benign monomers, terephthalic acid and ethylene glycol, which are then broken down further to produce CO2 and water. The researchers hope “these results will bring us closer to achieving an ideal model for PET recycling.”