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.
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!
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!
Anyway, this new species is named Ideonella Sakaiensis! (Don’t laugh too hard when I attempt to pronounce this during the podcast!)
How did this happen? Why did these plastic eating bacteria evolve?
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.
That’s a bit of a mouthful.
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.
Plus, the bonds between polymers don’t break apart with a chemical reaction the same way that natural compounds do.
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.
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.
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 IN HUMAN BLOOD
Update on March 22, 2022
Microplastics have been found in human blood for the first time by scientists who say the discovery shows the tiny particles can travel around the body and may even lodge in organs. (study on microplastics in human blood here)
So who came up with this idea for polymers in the first place?
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.
I’d love to talk more about natural polymers but let’s get back to plastics.
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.
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.)
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?
What is an enzyme? (photo from Wikiversity)
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!
CREATING THESE SUPER ENZYMES
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.
Then, they engineered a connection between the two enzymes to create a super-enzyme! This increased the plastic breakdown 3 x faster.
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.
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!
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.
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.