Bottiglia di plastica in mare

The plastic eaters

An important material for man, but also a great source of pollution. The solution is to recycle it or... eat it.

by Stefano Bevacqua
24 June 2020
5 min read
by Stefano Bevacqua
24 June 2020
5 min read

Scientific research has led to inventions and the development of technology, which over the past hundred years have played a crucial role in improving our ability to deal with a range of diseases, improving life expectancy and raising living standards. Among these inventions is plastic, a word which now evokes something of a dichotomy because of the way we use and consume this material. Let's look at how its use has become widespread and indispensable in relation to recent events, which have seen us grappling with the onset of the Covid-19 pandemic and imagine how we would have managed without it. Imagine an intensive care unit without plasma bags, IV tubes and protective visors. Or the shop around the corner without a Plexiglas protective barrier on its counter. These are just some examples of the importance of a material which has been somewhat demonised over the last few decades, in relation to plastic pollution, but which, when necessary, plays a decisive role in actively supporting our health systems and safeguarding our existence.

The pros and cons of plastics

This material is extremely useful and indispensable in many of the ways we use it. Think of bottles that were previously only made of glass, the smartphone that you're reading this on or the computer used to write it. Without plastic they would weigh and cost ten times more. But plastic is also a problem, because of the chronic and widespread way it is disposed of in the environment after its use. Now its advantages and most formidable qualities, its stability, chemical inertia and resistance to decomposition, have turned into defects. But as the pandemic has clearly shown, giving up plastic would be not only be detrimental; one might say it would be impossible. For many years now, the aim has been to find ways to produce, use and dispose of plastics that can reduce its dispersal in the environment as much as possible.

Through Versalis, Eni has been at the forefront of this work for many years, promoting various industrial strategies to solve the problems that come with plastic, without giving up its advantages. We are working on designing products that are easier to recycle and developing innovative technology to improve process efficiency. We have also joined the Circular Plastics Alliance, the plan launched by the European Union to boost the recycled plastics market. It is committed to ensuring 10 million tonnes of recycled plastics are used every year in the production of new products by 2025.

I mangiaplastica

Plastic: because recycling it is essential

A still underused resource

Let's begin with some figures, which illustrate the scale of the problem. 8.3 billion tonnes of plastic was produced worldwide from 1950 to 2015. Three quarters of this became waste and, of this amount, over three quarters ended up in landfill or dispersed in the environment. Yet this is an energy resource, in terms of waste-to-energy uses, but above all because of its potential for reuse. To take advantage of this resource, separating the waste is necessary. But this is just the first essential step of the virtuous cycle. The next is recycling and this poses its own difficulties and problems of various kinds. Plastics must be separated by type and colour to be able to use them at the end of the product's useful life. The physical characteristics of recovered products don't always allow them to be reused in all types of new production.

Plastic-eating bacteria

One solution is to dissolve plastic using the enzymes produced by some bacteria. This is an important breakthrough, especially for PET recycling, the acronym for polyethylene terephthalate, which is used to produce bottles or in the manufacture of polyester fabrics. PET accounts for about a fifth of all plastic produced worldwide and almost half of that is in plastic bottles. The very quality that makes PET ideal for liquid and solid food packaging, that it does not naturally decompose, is, again, its downfall. Worse still, if disposed of, it breaks down into tiny particles which remain in the environment.

The most common recycling techniques involve reducing PET down into reusable tablets, which then go on to be used in other production cycles. But only transparent waste can be processed in this way and the resulting polymer chain is much shorter than the original one, making it less useful. The ideal solution would be to split PET into its basic constituents, terephthalic acid and ethylene glycol. In 2016, a Japanese research team identified a bacterium called Ideonella sakaiensis, which produces an enzyme capable of degrading the PET chain into its basic elements. But reaction times are very long, making commercial use unlikely.

However, a French research group, jointly run by the Toulouse Biotechnology Institute and a private company, has managed to discover another family of bacteria capable of secreting an enzyme, a cutinase, which is very efficient in breaking down PET, ten thousand times faster than the microorganism discovered by the Japanese. This could be a decisive forward step, but only time will tell. In the meantime, the real revolution will come when we stop seeing the environment as a landfill that we can forget about, ensconced in the comfort of our homes.