Can Bacteria Break Down Plastic?

CAN BACTERIA BREAK DOWN PLASTIC?

Can bacteria break down plastic? Is there plastic-eating bacteria? This idea sounds like science fiction, especially considering plastic is man made.

Guess what???

Bacteria breaking down plastic is a thing! Not only is plastic-eating bacteria real, but this bacterium naturally evolved! Let’s look at how researchers are using these little beasties to advance biotechnology. For what, you might ask? To fight against plastic pollution!

IDEONELLA SAKAIENSIS

In 2016, Japanese scientists isolated a bacterium from outside a bottle recycling plant. Why, you ask? I have no idea, but it’s a good thing they did.

In their search the scientists discovered a new species: a species of plastic eating bacteria!

(For more reading on cool new species, try that article! Or this one.)

IDEONELLA SAKAIENSIS _plastic-eating bacteria
Nature outperforms humans yet again!

Anyway, this new species is named Ideonella Sakaiensis! (Don’t laugh too hard when I attempt to pronounce this during the podcast!)  

In just 80 years, evolution has succeeded in producing an organism that can defeat a man-made material—plastic—that did not previously exist in nature.

This bacteria breaks down polyethylene terephthalate (PET), a type of plastic used in soda bottles, among other things

Article about new bacterium species here!

How did this happen? Why did these plastic eating bacteria evolve? 

PLASTICS POLLUTION

Ideonella Sakaiensis is theorized to have appeared as a result of our  global environmental crisis. In response to the current crisis, microbes evolved the capacity to utilize synthetic polymers as energy sources. 

environmental crisis
courtesy Timothy Takemoto

That’s a bit of a mouthful. 

Can bacteria break down plastic Louie can't
Bacteria can break down plastic but Louie can't! Neither can the marine life.

WHAT ARE PLASTICS?

Plastic is all around us. This is a science blog after all, so let’s take a minute to look at its chemical makeup.

Plastics are polymers.

Plastics are polymers.
Polymers are long chains of repeating molecules. (these repeating molecules are called monomers.)
When heated in the presence of a catalyst, the monomers link together by forming extremely strong carbon-carbon bonds.
Until recently, nature hasn't seen these strong carbon carbon bonds.
This is why manmade polymers don't degrade
It’s estimated that a straw can take 200 years for the bonds to break apart.
A disposable diaper can take 450 years. The au natural poop will break down, though!
Organisms that break down other organic molecules took billions of years to evolve.
Termites have enzymes to decompose cellulose, the same way cows eat grass and we eat apples.
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Plus, the bonds between polymers don’t break apart with a chemical reaction the same way that natural compounds do.

Not all polymers are manmade. One of the most important natural polymers is DNA!

Cellulose and chitin are a few more.

Over prolonged periods exposure to sunlight (UV light) can result in photo-degradation of plastics. This exposure often results in the fragments of plastic becoming smaller and smaller. 

Enter a new issue. Microplastics.

Welcome to our Home Page Science Blog
UV light breaks bonds in natural polymers but not manmade polymers.

MICROPLASTICS

While photodegradable plastics–plastics capable of being broken down by light–may break down, if you read the fine print, the truth is that these plastics never completely degrade! They divide into tiny pieces called microplastics.

GREAT PACIFIC GARBAGE PATCH
This name is a misnomer. There is no island of trash in the middle of the ocean.
The debris is there, but not easily seen from a boat.
Because it's mostly microplastics
Microplastics of the Great Pacific Garbage Patch can simply make the water look like a cloudy soup.
GROSS.
Most large debris in the Great Pacific Garbage Patch is made up of inexpensive fishing nets.
GHOST-FISHING
Ghost fishing happens when these discarded nets continue to "catch" marine life—suffocating marine mammals
NOT FUNNY!
This turtle was saved by NOAA divers who happened to be on a clean up mission
HAPPY ENDING
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That turtle was saved (!!) but here’s another horrible fact: microplastics have been detected in the air. 

A recent study found microplastics in the atmosphere in a remote region of the French Pyrenees. 

Now we’re breathing this stuff in? 

Microplastics even litter the air.
Microplastics even litter the air!

So who came up with this idea for polymers in the first place?

Monomer to polymer
Chemical reaction creates a polymer

HERMANN STAUDINGER, THE FATHER OF POLYMERS

Prior to the early 1920’s, chemists doubted the existence of molecules having molecular weights greater than a few thousand units.

In retrospect, this limiting view seems ludicrous, then again so is showing anyone a YouTube video after you’ve watched it. They are never funny to anyone else. No idea why. Thankfully, some are informative!

Staudinger presented sound experimental evidence to support the existence of high molecular weight polymers. It took twenty years before the science community accepted his polymer theories.

Hermann Staudinger father of polymers
Photo from the Nobel Foundation archive

He studied natural compounds such as rubber and cellulose.

We now know these are natural polymers.

He formulated a polymeric structure for rubber, based on a repeating isoprene unit (aka monomer)

For his contributions to chemistry, Staudinger received the 1953 Nobel Prize.
Here's his Nobel prize speech

I’d love to talk more about natural polymers but let’s get back to plastics.

DNA building blocks ATGC
DNA!
Polymer formulas
A few polymer formula examples. Scientists are busy people. I do applaud Kevlar!

WHY DO WE NEED PLASTICS?

Plastics were originally developed to avoid the use of animal-based products: I can see why people would want to do that. 

baby cow
Don't eat me, I'm too cute.

Fast forward almost 80 years.

Now, plastic is easy to hate. I’m pretty riled up researching and writing this post.

But let’s think about this. What’s good about plastics? (partial list below.)

Bacteria-eating Plastics fight pollution
Why can't someone wade in and pick this up?
PROTECTION
Plastics protect vulnerable products from damage whilst in transit and from contamination and/or damage by moisture, humidity, gases, microorganisms, insects, and UV light.
REDUCE WASTE
By increasing shelf life of products
REDUCE FUEL CONSUMPTION
Their lighter weight makes it more economical for transporting goods. This also reduces carbon emissions.
HEALTH
25 % of all medical plastics & 70% of disposable medical applications are made of vinyl, including blood, IV bags, supporting tubing. GLOVES!
INSULATION
This revolutionized safely getting one my my favorite things--ELECTRICITY-- to many people.
NOT TO MENTION SEALS!
Not the adorable seal above, but the seals on aircraft fuel tanks and refrigerator doors. Etc.
NO CELL PHONES OR COMPUTERS
ouch
WE'D BE RESTRICTED TO WOOL & COTTON & ANIMAL HIDES
Cows are grateful.
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Okay, it would be tough to live in our society without plastics. That said, plastics are clogging our planet, which is why scientists thought that these small but mighty bacteria needed investigation. After they answered the question, ‘Can bacteria break down plastic?’ researchers  wanted to know how.

What is the bacteria’s secret weapon in actually breaking down plastic?

My first butterfly is born
My monarch enclosure is plastic! Click on the photo to read about how I raised monarchs from eggs.

ENZYMES!

What is an enzyme? (photo from Wikiversity) 

What is an enzyme
Example of 3D structure of an enzyme
An enzyme is a biological catalyst.
Click Here
The point of a catalyst is to increase reaction speeds.
Enzymes are proteins.
Like all proteins, enzymes are made from strings of amino acids.
Our DNA directs our cells to string together 100s to 1000s of amino acids in a specific and unique order
Our cells make 1000s of enzymes to speed up chemical reactions for different functions.
ENZYMES ARE HIGHLY SPECIFIC
They assist (or catalyze) specific reactions and specific materials
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CAN BACTERIA BREAK DOWN PLASTIC?

After the Japanese scientists published their findings, the science community at large was skeptical. (I saw several such comments in publications.) 

After all, how is it even possible that a bacterium would evolve that could use plastic as its major energy source? In only eighty years?

This reminds me of the experts who were skeptical of the father of polymers! 

10 great scientists and their discoveries
A tough crowd to convince
The scientists showed that Ideonella sakaiensis produced two enzymes...
...capable of breaking down plastic (a polymer, as you know) into its monomer components.
Polymers that have those strong carbon carbon bonds!
More research followed, which proved the claim.
Click Here
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CREATING THESE SUPER ENZYMES

Researchers took it to the next step.
They used a machine with a powerful, high energy electron beam to decode the enzyme structure.
A SYNCHROTRON
They were able to figure out the amino acid sequence for both enzymes!
Click Here
They used a different bacteria and coded it to make these enzymes.
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Their first enzyme PETase, worked 20% faster than the natural enzyme.

PETase breaks down polyethylene terephthalate (PET) back into its building blocks! Or monomers. 

This means that the monomers could potentially be recycled infinitely. 

ENZYME PETase
Super enzyme PETase

Then, they engineered a connection between the two enzymes to create a super-enzyme! This increased the plastic breakdown 3 x faster. 

super enzyme
Combining two separate enzymes into a enzyme cocktail
super enzyme
Sadly, excessive alcohol consumption makes the list (courtesy Carolyn Holton)

Maybe the researchers celebrated with that mango martini!

Obviously, researchers have a ways to go, but this is a significant leap forward in our fight against plastic pollution.

BIODEGRADABLE PRODUCTS....BAMBOO!

Obviously, we can try to stop using some plastics, like asking the takeout guys not to include utensils. I did find this cool company that has a lot of products made from bamboo. 

Bamboo is actually grass! It’s fast-growing, needs no fertilizer, and self sows from its own roots. It produces 35% more oxygen than a tree of the same mass. And pandas love it!

Bamboo is sustainable make sense of science
Bamboo products are highly sustainable

The start up company- Global Wake Cup-  is offering you a 10% discount on any products. I think I may get about ten cents if you click on the link (!!) I’m happy that it’s not amazon. And these straws are cool. Enter SBK10 at checkout. 

Bamboo Straws biodegradable
Click on the photo or link above to check out their offerings

STEM ACTIVITY

While biotechnology advances, you can turn this into a STEM activity with your kids or grandkids. Wear those plastic gloves (!!) and go to the park or shore. Pick up some plastic trash. Recycle it! And tell them about polymers.

Buy them some cool bamboo straws, too. 

 

Plastic waste beach

Check out NOAA’s webpage for other ideas about how you can help with the fight against plastic pollution.

Louie wants to help, but he doesn’t have opposable thumbs!

Nor does he have the enzymes in his GI to break down plastic polymers.

But we know the enzymes are out there. Thank-you, Mother Nature, for the plastic-eating bacteria.

The fight against plastic pollution and Louie
Louie will keep you company while you clean up!
Make Sense of Science__ Sue Berk Koch_Kev
No plastic pollution in sight. Did these guys clean up?

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44 thoughts on “Can Bacteria Break Down Plastic?”

  1. Great post and one of my favorite so far. But being the pessimist I am I would be concerned if these things would mutate and start breaking down plastics that we need to keep food fresh etc. I guess time will tell. Keep up the good work. Mike

    Reply
  2. I’ve been meaning to pick up some reusable straws so thanks for the link. I learned a lot from this post about enzymes and polymers. Thank you.

    Reply
  3. An important topic and very informative post!  Thanks! When they stopped allowing recycled bags at the grocery store, and I started hauling home all those plastic bags – it gave me the hives!  I know countries in Europe that started changing 10 cents for a plastic bag and it reduced use something like 80 percent!  Here’s to a more environmentally friendly alternative! 

    Reply
    • I too was dismayed when I had to go back to the grocery plastic bags! A small detail during a pandemic but it was dismaying just the same. I’m pleased that you found my post informative! Thanks.

      Reply
  4. I remember coming across the plastic eating bacteria years ago, but nothing seemed to follow on from the original claim. I’ve also seen countless plastic alternatives that are completely environmentally friendly and work just like regular plastic, but again, nothing seems to come from it. I guess it compaines aren’t willing to change it doesn’t matter how good your plastic alternatives are

    Reply
  5. This is so interesting. Plastic had definitely become a problem and I think we relied on it for packaging for too long instead of looking for alternatives all along.

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  6. Amazing post! Thank you for sharing this important and informative post! This is another really detailed post that I love! I have been trying to use less plastic to help save the planet!

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  7. This was such an interesting and informative post. Plastic packaging is definitely becoming more and more of a problem for sure. Thanks os much for sharing!

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  8. This is a such an amazing informative post, your knowledge of specific subjects is amazing and I believe the post you’ve written here is an important factor we need to think about in the future.

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    • That’s such a lovely compliment! I agree, we need to stay vigilant. The pandemic has taken its toll on humans, and that’s nothing to make light of, but we can’t forget about our planet. Thanks, Luke!

      Reply
  9. That’s fantastic news! I wrote about micro-plastics a while ago when they first crossed my radar, but did not know that a potential solution to the environmental crisis had been devised. The resilience of both nature and human ingenuity is remarkable, thanks for this incredibly informative post!

    Reply
    • I’m glad that you found my post fascinating! I’m trying to find a balance between the backmatter and the headline, so people can make sense of the science and not roll their eyes! Thank you.

      Reply
  10. Absolutely fascinating read! I feel like plastic has always been considered the easy route – but really now we need to be more careful and think about other options. It’s one of the things I’ve been noticing when I order online, if they say how they package it (particularly eco-friendly) – my online shopping has increased a bit since I haven’t really been leaving the house unless I have to.

    Very interesting though, I think it’s brilliant that you can give a science lesson, make it fun and interesting, and most importantly help make people understand the why’s and how we can help. Why something like this is important to learn about. Brilliant! Thanks so much for sharing!

    Reply
    • I haven’t looked for ‘eco-friendly’ when I shop online. Great tip! I’m gratified that you think I’m sneaking in science in a fun and interesting way. That’s my objective, so I appreciate you mentioning this! Thank you!

      Reply
  11. This is a great post! So interesting and I love that you’ve included different viewpoints especially how plastic started as a positive thing and still can be, to a degree. There’s definitely a lot that needs to be done about plastic pollution though. The plastic eating bacteria sounds… interesting!

    Reply
    • Plastic is a positive thing. Imo, it has become too much of a good thing! Maybe we can harness these little bacteria to help us. Bacteria and viruses are powerful. Look at covid. Okay, maybe don’t do that, but you understand all too well. Thanks, Jenny!

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  12. This reminded me of one of our science subscription boxes where we learned about polymers and DNA. I had heard about a plastic munching bacteria but not paid that much attention so your post was absolutely fascinating – so detailed and useful (as always) thank you, Sue! Lisa

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  13. I love how you explain all the science behind such a complicated process! The fact that nature can help lessen manmade waste and pollution gives me so much hope for the future. I will continue to do my part to reduce my use of plastic.

    Reply
  14. This was such an interesting post! Plastic sounding bacteria sounds like it has the potential to be incredibly useful for the planet but I guess time will tell.

    Tash – A Girl with a View

    Reply
  15. Quite informative. While it does protect the subject from humidity etc but the plastic chemical in itself also harms the product too. It also causes leeching. But about the bacteria, I’ve heard of it and yes there was a project on it too. But what I heard or maybe knew was that it only degrades a certain plastic type. Only one regardless is biodegradable but only to an extent, the rest are not. Regardless learned some from your post. Just thought to add a perspective or insight, whichever is factually right. Thanks for sharing x
    Isa A. Blogger
    http://bit.ly/39f9FN0

    Reply
    • Yes, these particular enzymes only break down a specific polymer. Enzyme science has a way to go before it can make a dent in our mountains of plastic waste. But we have to start somewhere. Thank you for sharing your knowledge!

      Reply
  16. Wow, this is such a great post, thanks so much for sharing some fab information as always! I’d heard about microplastics being detected in the air which is quite concerning! I’ll definitely have to check out those reusable straws you’ve mentioned, I keep meaning to purchase some.

    Reply

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