A team of Japanese scientists has discovered a bacteria that’s evolved to break down and consume PET—one of the world’s most environmentally damaging plastics.
The team discovered the bacteria living on plastic items found in wastewater samples it was collecting. Called Ideonella sakaiensis, it appears to consume a diet made up exclusively of PET, which it breaks down using a pair of enzymes. The bacteria cling to the plastic, then break the plastic down into terephthalic acid and ethylene glycol in a two-step process. They then digest those two substances. PET was only invented about 70 years ago. That means the bacteria must have evolved the ability to consume the plastic over the intervening decades. The results are published in Science.
The team is obviously excited about the prospect of using the bacteria to clean up the planet. There are, after all, millions of tons of waste PET on the surface of our planet—on landfills and in our seas. But right now, the bacteria are inefficient: New Scientist reports that it takes “6 weeks at 30°C to fully degrade a thumb-nail-sized piece of PET.” That’s because the bacteria multiplies relatively slowly, so it may be possible to genetically engineer a bacterium that combines the speed of multiplication of something like E.coli with the plastic-chomping abilities of Ideonella sakaiensis.
It’s not the first natural organism to consume plastic. In 2012, there were reports of an Amazonian fungus that was able to break down polyurethane. But in terms of cleaning the planet, bacteria could be far more efficient. Let’s see if the team can speed the process up.