A plastic-eating enzyme was developed by researchers at the University of Texas, which could prevent billions of pounds of plastic from ending up in landfills.
Followers of science news may remember stories like Science Fair Project Isolates Plastic-Eating Microbes from 2008, about a 17-year-old science fair winner who got bacteria to degrade plastic bags by 43%, or New Enzyme Discovery is a New Step Towards Beating Plastic Waste from last month, about British scientists who discovered an enzyme that could degrade PTA, a component of plastic bottles.
You've probably seen numerous articles with titles that sound similar: "New super-enzyme eats plastic bottles six times faster," "Plastic-eating bacteria could help aid global recycling efforts," etc. These articles give the impression that there is a magic bullet—which is unquestionably recyclable—that will solve the world's enormous plastic problem.
Why is it taking so long? Why are these microorganisms just lurking around while we're dealing with a crisis?
It seems there are a few reasons why things aren't straightforward:
There are many kinds of plastics, and bacteria can only deal with one or two of them under certain conditions
Many enzymes or bacteria only work for one specific kind of plastic, and much of our trash combines several kinds of plastic.
Most plastic-recycling efforts focus on PET, the plastic used in plastic bottles. PET represents about 20% of global plastic waste. It’s chemically easier to break down than polyethylene or polypropylene, types used in plastic film and food packaging.
That’s an important caveat: most of these solutions would only put a dent in our plastic problem, rather than solve it entirely.
Frequently, the processes or microbes only function at particular temperatures, in particular habitats, or after a certain amount of time has passed. The less viable it is to accomplish anything at scale, the harder it is to create the conditions. This also implies that microorganisms are unlikely to address the problem of plastic pollution in nature.
These specialty bacteria are really expensive
These procedures could be pricey. Additionally, the majority of treatments merely reduce plastic to its monomers, which are essentially only useful for producing new plastic.
This has two issues: first, it doesn't lower the amount of plastic in the world, and second, it already costs very little to make more plastic. Building an expensive facility, transporting loads of waste there, and letting microbes slowly produce elements that are worth next to nothing and still aren't biodegradable is neither a good business strategy nor, in some cases, an effective use of tax dollars.
These bacteria are not very efficient under natural conditions and there is a risk of spreading
A common misconception is that these bacteria might be released to consume the enormous amounts of plastic that are now in our landfills, oceans, and litter.
However, even if an enzyme or bacteria could function in completely uncontrolled circumstances, they might produce hazardous byproducts, damage currently-used plastic, or need to be released in extremely large numbers in order to have an impact.
Therefore, these technologies are not a completely new alternative at this time, but rather could only be utilised within our current recycling systems. All the plastic that we want the bacteria to eat will still need to be sorted, gathered, and processed.
We don't have plastic-eating bacteria that could be used on a large scale, but there's recent good news
Researchers are tackling these issues, and the situation is becoming better from Japan to Saudi Arabia to the US National Renewable Energy Laboratory.
For instance, a recent discovery from UT-Austin revealed an enzyme that can break down plastic in a couple of hours and function at a temperature that is quite accessible at 50 Celsius (122 Fahrenheit). And an AI program that could iterate and boost performance was used to find it.
And the first demonstration facility for the recycling of plastic using enzymes just started operating. It is operated by the French company Carbios, who recently declared success in producing new PET plastic bottles using a method that renders them perpetually recyclable.
That is a development that merits acknowledgment. Even while plastic can currently only be recycled into lower-quality plastic for specialized applications like carpeting (over 80% of plastic cannot be recycled, including over 90% in the US),
Traditional mechanical recycling methods need garbage to be sorted, shredded, cleaned, melted, and pelletized—and discard any batches contaminated with food or incompatible materials. They are costly and inefficient. Chemical recycling procedures frequently produce noxious byproducts on their own.
While Carbios doesn't anticipate their plastic to be as inexpensive as newly created kinds, they do hope environmentally conscious businesses and customers will pay a little bit more for it. Carbios plans to build a commercial-scale factory by 2024. Additionally, its strategy will make it possible to recycle plastic from mixed waste more effectively and with less waste.
If innovative procedures can help reduce our plastic problem, only time will tell.
Meanwhile, MIT's cellulose-based solution and businesses that use microbes to generate sustainable materials are all developing biodegradable alternatives that can completely replace plastics. European governments are adopting a different strategy and prohibiting plastics that are more difficult to recycle.
Of course, you don't have to wait for any of them; people all around the world are coming up with innovative ways to cut back on their own use of plastic. We don't have to rely on magical microbes to do our dirty work, as exciting as they may be.
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