A group of plant and molecular biologists from the University of Kelaniya and the University of Peradeniya in Sri Lanka has made an intriguing discovery.
They observed that numerous hardwood-decaying fungi, which are known for breaking down hardwood trees containing lignin, are also capable of breaking down polyethylene, a common type of plastic. Their study, reported in PLOS ONE, involved testing 21 different species of hardwood-decaying fungi in a laboratory setting.
Previous research has already identified around 430 species of fungi and bacteria with the ability to degrade various types of plastic. However, the researchers stumbled upon a new species that not only breaks down hardwood trees but also shows promise in degrading polyethylene.
The investigation began when one of the team members noticed certain fungi breaking down dead hardwood trees in a forest reserve. Breaking down hardwood is challenging due to the presence of lignin, a robust polymer.
Previous studies have shown that fungi use potent enzymes to break down such materials. This led the researchers to wonder whether these fungi could also handle man-made polymers like polyethylene.
To explore this possibility, the team collected 50 samples from the forest and isolated the fungi by species in small sample jars back in the lab. They placed some jars with sheet plastic and others with both plastic and wood. These jars were stored at a temperature of 28 to 30° C for 45 days. After this period, the researchers examined the jars and their contents to determine whether the fungi had broken down the wood or plastic. They used a regular scale to measure the weight changes in the wood since the breakdown of lignin in wood results in the release of carbon dioxide, making the wood lighter.
The team made a fascinating discovery—every type of fungi tested successfully broke the plastic sheet. Surprisingly, they found that more plastic was consumed when wood was absent. This research could have significant implications for tackling the growing problem of plastic waste worldwide. Using fungi to degrade plastic waste could potentially be a valuable approach to managing the vast amounts of plastic produced each year.
