What trees can teach us about plastic
A splintering crack is followed by a slow rumbling, as a tree falls to the ground. After standing and watching over the secrets of the forest for centuries, this tree has finally laid down. This happens time and time again in forests. And when we get to walk through these forests, we witness the magic of these fallen trees. Turkey tail mushrooms grow out of the side of these logs like tiny balconies made just for faeries to land on and survey the world. The moss climbs over them, transforming dark wood into vibrant and varying shades of green. There is mystery and magic in each of these small scenes. We can see where pieces of the log, once whole, have dropped off in pieces, slowly returning to become soil.
Fallen trees couldn’t always decompose
But about 380 million years ago, this story did not happen. 380 million years ago, a tree would fall in the forest, and it would lie down next to all of the trees that had come before it. Dead but never decomposing. 380 million years ago trees littered the ground much like the way plastic litters the ground today. Accumulating. Dead but eternal. This was during the middle of the Devonian period, when trees first evolved. Over time, the rise in global plant matter meant that CO2 was pulled out of the air and high amounts of oxygen were emitted back into the atmosphere. A high oxygen content meant that things would just… combust. And for 80 million years that was the cycle for plants and trees. They would grow, pull CO2 out of the air, emit oxygen back into the air. The oxygen would create huge fires, burning up the plant matter, and emitting CO2 back in the air.
Why? Why did these trees pile up? Woody plants and trees have a special component that helps them create trunks that protect them from fire and disease. In fact, it is the component that helps them make trunks in the first place. And that is lignin. Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants, things like wood, bark, It’s a complex biological substance, and 380 million years ago there was nothing in existence that could break it down. It took 80 million years for the first bacteria and fungi to develop that could break these molecules apart and break them down. For 80 million years the plants and the trees piled up, compressing under their own weight to create coal and sitting in swamps to create peat bogs.
A modern day, synthetic lignin
And all I can think of when I read this is… plastic. Humans have created a modern day lignin, and it’s plastic. Now, I’m not a scientist, but here is what I do know (or think I know): A polymer is a large molecule, composed of a long chain. Each link in the chain is called a monomer, and is a smaller component of this large molecule. Polymers can are both unique and complex because they are so large and made of all of these monomers.
Lignin and plastic are both polymers. Lignin is a biopolymer while plastic is a synthetic polymer, but that synthetic polymer is made from petrochemicals. Basically, we made a synthetic lignin, and we need to figure out a way to break it down into monomers. Those monomers can’t decompose, but they can be metabolized by bacteria. Basically a bacteria that eats plastic. I talked about this a few years ago in my newsletter. I discussed a bacteria that was found to have evolved in a Japanese dump, feasting on plastic, and a student at Reed College who isolated and bred three different kinds of plastic-eating bacteria. But I’ve been curious, how have things evolved (pun intended) since then?
What we can learn from fungi and bacteria
Now in 2026, scientists have now identified over 200 different enzymes and more than 436 species of plastic degrading bacteria, and fungi, that work on breaking down different types of plastic. Scientists are working on amplifying these enzymes so that plastic can be broken down more quickly, and in some cases use the broken down materials to re-make plastic as a resource saving measure.
Researchers have bio-engineered an existing enzyme in the bacteria Ideonella sakaiensis to break down PET plastics in hours to days at lower temperatures. Previously the process took months and required higher temperature to work. Researchers have successfully degraded 51 types of PET products so far.
Scientists have also identified a few new PET-degrading enzymes in areas where they weren’t previously known. Scientists have identified a novel PET-degrading enzyme in sewage-sludge bacteria, specifically Comamonas testosteroni. The enzyme is able to eat through polymers like those found in laundry detergents and degrade the polymers to the monomers. They’ve also found a new PET-degrading enzyme(PET46) in microbes from deep-sea environments. At the molecular level, PET46 is very similar to another enzyme called ferulic acid esterase, that degrades lignin in plants. Scientists know that lignin and PET have many structural similarities, so the PET-degrading enzymes found in nature may also be important for composting wood in forest soils, for example. This is exciting because it shows that these plastic degrading enzymes are present wherever our plastic may end up; be it in the sewer or in the ocean. It really highlights how prevalent the plastic problem is, if they’re identifying plastic eating microbes out in the deep sea.
Researchers have also started to learn that bacteria, fungi, and enzymes can eat through biodegradable plastic easier and more quickly than traditional plastics. Maybe this could help change our consumption model for plastic so that short use or single use plastics are only biodegradable plastic? This could even be helpful as part of a larger step of phasing out plastics for day to day use altogether. The last several years of research have shown that these plastic degrading enzymes, bacteria, and fungi are more prevalent than we once believed. When we look away, even briefly, it’s easy to forget that nature is always working through problems. And once again, a synthetic problem that we made has the potential to be addressed through nature, either by us letting it solve the problem or even with a little nudge to help it move more quickly.
Resources
Great Moments in Plant Evolution, Part 2: The Origin of Trees and Forests
The Shocking Truth About Lignin, How Nature’s Toughest Material Breaks Down
Plastic eating microbes could help tackle our environmental mess
Do microbes prefer biodegradable plastic?
How a plastic-eating enzyme could inspire a truly circular economy