Plastic-Eating Bacteria Could Help Clean Up Waste (inhabitat.com)

Kristine Lofgren writes: Japanese researchers have discovered a microorganism that literally devours ocean-clogging plastic. The bacterium Ideonella sakaiensis can completely break down polyethylene terephthalate (PET), a common plastic used in bottles and containers. That type of plastic makes up a huge proportion of all the plastic waste in the world, particularly in the ocean. The bacterium uses a pair of enzymes to break down PET and turn it into a food source. The problem is, it takes up to six weeks for the bacterium to completely breakdown a small, low-grade sample of PET. Microbiologist Kohei Oda of the Kyoto Institute of Technology co-authored the study published this week in the journal Science, and he told PBS NewsHour he was "very surprised to find microorganisms that degrade PET" because the plastic has always been thought to be non-biodegradable. Now, scientists just need to figure out how to harness the hungry little bug to recycle plastic and reduce pollution.

Comments

No reason for alarm

[Mal-2]

I don't think there is anything to be concerned about. They didn't engineer this bacterium, they discovered it. Yet we don't have a massive epidemic of credit-card-eating bacteria everywhere. Why? Probably because although they can eat it, it isn't their preferred food source. Now if someone knocks out some metabolic pathways so that they have to eat plastic to survive, then maybe we'll have something to worry about.

PET is already very recyclable

[Thruen]

PET is one of those plastics that's very easy to recycle already, people just don't do it. And I mean really easy to recycle, I make and sell poker chips that are made largely out of recycled bottles (that's PET) and any bad part can simply be ground up and thrown back in the hopper so the material is used again. Obviously there's a little more to recycling used bottles and whatnot, but the point is it's already really easy to recycle PET compared to many other materials. While I understand this isn't the same as nature being able to break it down, I don't understand what the big benefit to this over standard recycling. There is a much larger problem when it comes to recycling and that's the willing participation of the general population. Where I live we get fined for failing to sort recyclables, and people still don't do it. Solving that seems more important if you ask me.

Re:PET is already very recyclable

[CanadianMacFan]

I was listening to a podcast and they brought this up. Unfortunately I listen to a number of science ones and I can't find which one it was. But what I got from the interview was that they would like to be able to engineer the bacteria so that it would stop eating the plastic part way leaving it as the copolymers that went into making the plastic in the first place.

The reason that PET plastics are durable is that the bonds between atoms and molecules are strong. To break these bonds requires a lot of energy. Most recycling of plastics takes the old plastic, chops it into pellets, and melts it into the new product. But the new product is almost never as good in quality as the original. Drink bottles don't go back to drink bottles. They use virgin plastic. Drink bottles get recycled into carpet or benches. Very useful things but you still need something to create the drink bottles from.

The idea is that if you can use the bacteria to break down the PET into the copolymers without using a lot of energy then you can create "virgin" plastic suitable for any use without having to use fossil fuels as a source for plastic as you do today. There are projects looking at replacing fossil fuels with oils obtained from agriculture and those will still be needed since our demand for plastic is growing and our recycling rate is 100%.