Newly discovered bacteria can eat plastic bottles
A team of Japanese scientists has found a species of bacteria that eats the type of plastic found in most disposable water bottles.
The discovery, published Thursday in the journal Science, could lead to new methods to manage the more than 50 million tons of this particular type of plastic produced globally each year.
The plastic found in water bottles is known as polyethylene terephthalate, or PET. It is also found in polyester clothing, frozen-dinner trays and blister packaging.
"If you walk down the aisle in Wal-Mart you're seeing a lot of PET," said Tracy Mincer, who studies plastics in the ocean at the Woods Hole Oceanographic Institution in Massachusetts.
Part of the appeal of PET is that it is lightweight, colorless and strong. However, it has also been notoriously resistant to being broken down by microbes-what experts call "biodegradation."
Previous studies had found a few species of fungi can grow on PET, but until now, no one had found any microbes that can eat it.
To find the plastic-eating bacterium described in the study, the Japanese research team from Kyoto Institute of Technology and Keio University collected 250 PET-contaminated samples including sediment, soil and wastewater from a plastic bottle recycling site.
Next they screened the microbes living on the samples to see whether any of them were eating the PET and using it to grow. They originally found a consortium of bugs that appeared to break down a PET film, but they eventually discovered that just one of bacteria species was responsible for the PET degradation. They named it Ideonella sakainesis.
Further tests in the lab revealed that it used two enzymes to break down the PET. After adhering to the PET surface, the bacteria secretes one enzyme onto the PET to generate an intermediate chemical. That chemical is then taken up by the cell, where another enzyme breaks it down even further, providing the bacteria with carbon and energy to grow.
The researchers report that a community of Ideonella sakaiensis working this way could break down a thin film of PET over the course of six weeks if the temperature were held at a steady 86 degrees Fahrenheit.
Mincer said the study was impressive and did a good job showing that these organisms were eating the plastic pretty well. However, he said it was not immediately clear whether or not it would help keep plastics out of the ocean, for example.
"When I think it through, I don't really know where it gets us," he said. "I don't see how microbes degrading plastics is any better than putting plastic bottles in a recycling bin so they can be melted down to make new ones."
He added that the research could make it easier to identify other microbes that might have similar PET-degrading capabilities.
"This process could be quite common," he said. "Now that we know what we are looking for, we may see these microbes in many areas around the world."
Explore further
S. Yoshida et al. A bacterium that degrades and assimilates poly(ethylene terephthalate), Science (2016). DOI: 10.1126/science.aad6359
©2016 Los Angeles Times
Distributed by Tribune Content Agency, LLC.
User comments
http://www.mnn.co...-plastic
Will there be any space for us unengineered species in this faux world? I suspect those enjoying the feast of artificiality will have so strong a chenical attack set of molecules and enzymes that we would be dessert.
You haven't heard about CRISPR?
That would be a highly desirable co-process.
Do add 'people' to your long list of 'techie-modified' items: recent news reports show a community of people who are implanting chips under their skin, to "make a better, more capable human" .. I didn't just make this up!!!
PET eating organisms may be new -- but when I researched plastics in the oceans, I found nothing particularly different about PET -- all floating plastics breakdown and eventually disappear.
Plastics that sink take longer to break down -- some may not break down at all -- in which case they become like rocks -- home for various plants and creatures.
Well, gollygee, Mr. Kippers --everything's sunshine and moonbeams!
We are as much 'engineered' by evolution as any other species, moreover we are one of a few social species that have changed ourselves. (Smaller teeth and snouts due to 3 Myrs food technology; larger, more expressive faces; cryptic estrous; et cetera). And of course we have changed our companion species the last 10 kyrs, in the risky - as always - process of selection, where 10s of thousands of alleles inadvertently sweep with the traits that we want to change.
And out of the ten or so modern, more precise (less risky), genome modification methods, some are applied today to help with problems. Tomorrow they will be used for body modification. (But it is unlikely they will fix in the population.)
3 Myrs old dedicated 'engineering' on top of 4 billion years of unspecific one. That is a whole lot of capable evolution! (Which is why these new bacteria species evolve.)
Well, gollygee, Mr. Kippers --everything's sunshine and moonbeams!
This research is quite interesting. When they drag nets through the water, they find micro-bits of plastics - increasing in number as the size goes down -- until a certain size below which the numbers drop to zero. The disappearing plastic had all perplexed until the discovery that microbes were eating the plastic. Like ice, small bits have a high surface area to volume ratio -- the microbes thus consumed the whole bit.
What this means is that we can not remove the plastic from the environment -- it returns to the environment naturally by becoming food for microbes. If we quit putting plastic into the sea, it will be consumed, just like oil that leaks from the sea bed.
That's right, it can't be completely removed from the world ocean, because most of it is much too small.
But your claim that it is consumed and broken down by marine life is fatuous --it remains plastic in the animal's body until it dies or excretes it, just as it would in your own.
Breaking plastic into smaller and smaller pieces doesn't render it non-plastic, sub-plastic, or otherwise. It remains plastic and it remains harmful for a host of reasons.
It is not consumed and chemically degraded by bacteria as are at least some portion of oil and methane.
This is an essential fact that must be understood.
This is an essential fact that must be understood." is essentially incorrect.
It is correct in that when an albatross scoops up a bit of plastic, the plastic passes more-or-less unaltered through the bird's digestive system and is excreted, like a marble swallowed by a human baby.
Also, plastics breaking down in the sea into smaller and smaller pieces likewise does not make them disappear.
What does make them disappear is detailed in this research: http://www.nature...191.html titled "Marine microbes digest plastic". This discovery has been followed by much more research into this topic. The bottom line is that microbes do in fact consume oceanic plastic making it "disappear".
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