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The Revolution of Plastic-Eaters

The accumulation of trash, especially plastic, over the last century is becoming an important issue regarding the pollution of the landscape. Moreover, it is causing a problem in terms of harming biodiversity. The thing is, plastic has always had a great role in economic development. We can do nearly everything with this material. But, what if the scientists had found new bacteria with the ability of decomposing plastic?

It is no lie that our world is constantly threatened by human activities, to the point that the Earth has even tried to adapt to the coming change. According to research done by Thinkstock, in 2013, we had produced only a total of 56 million tons of plastic in the world. In 2014, however, we produced the astonishing number of 311 million tons. In fact, plastic is the most residual material we discard. Nearly every daily-use object is made out of plastic since it is hard, resistant, has precise elasticity, and can be transparent.

We mainly use plastic which includes, which stands for polyethylene terephthalate and is the most common thermoplastic polymer resin of the polyester family. It is primarily used in fibers for clothing, containers for liquids and foods, and thermoforming. It is a long-life material in natural environments when not managed in a proper way. We use this plastic mostly for bottling, it represents 16% of the total amount of plastics we produce. Furthermore, its inefficient recycling makes it difficult to biodegrade, taking between 100 and 1,000 years to decompose completely.

Ideonella sakaiensis is the name that a group of researchers led by Dr. Kohei Oda from Kyoto’s Institute of Technology decided for these bacteria back in March of 2016.  Their main goal is to speed up the decomposing action, which would shorten the process up to a couple weeks thanks to two of the main enzymes it produces: PETase and MHETase.

These two proteins allow Ideonella sakeiensis to process and eat plastic; the enzyme PETase is expelled by the bacteria itself and transforms PET in an intermediate compound (called MHET), then swallowed again. Then, inside MHETase intervenes and the compound is disintegrated. What we at first called PET is now separated into two basic compounds: ethylene glycol and terephthalic acid, both easily recycled and reused.

This idea is not new; fungi capable of eating plastic had already been discovered in the past, but producing them artificially was not so simple. This time, they have been able to recreate in the laboratory the enzymes of the bacteria that are in charge of the process, so there is hope to be able to modify them genetically to create more efficient types of bacteria.

What’s more, this breakthrough raises a big evolutionary enigma as PET plastic has only existed for seventy years. This means that the bacteria is probably years younger (more or less, when recourses started to accrue) than its food source. During the next few months, scientists will be able to investigate this new bacterium, whose genes only activate in the presence of PET, to see if it is possible to adapt it to other types of plastics. If so, we could be facing an ideal solution to the problem of recycling and treatment of plastic waste, which threatens our planet and becomes a bigger problem year after year.

Editor: Kaylynn Crawford, Ruby Halfacre, and Shreya Singireddy