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AIf you're reading this, a strange object that looks like a 2000-foot floating pool noodle drifts slowly across the north-central Pacific Ocean. This object is designed to solve a huge environmental problem. In doing so, he draws attention to a number of others.
It is estimated that 5,000 billion pieces of plastic float in the world's oceans. The mass noodle will cross the Great Pacific Garbage Patch, under the effect of wind and currents, and pick up the plastic she will encounter on the way. Ocean Cleanup, the organization that has developed the device, promises "the greatest cleaning of history".
See also: The Great Pacific dump is officially twice as big as Texas
If it works, the device – called discreetly System 001 – could make a difference in the huge amount of plastic carried by the ocean. But once the plastic is collected, the options are not good. This is where an environmental ethicist like me begins to think about the future of this plastic. Of course, the ocean is better without it, but the problem of plastic has many more layers than it seems.
The fight of the sort
Plastic recycling is only possible if it can be meticulously separated into different types of chemicals. What people generally describe with the single word "plastic" includes seven main types of materials – those used to make soda bottles, trash bags, plastic bags, shopping bags, yoghurt pots, nets fishing, foam insulation and nonmetallic parts of many household appliances. Recycle each of these types, which you may know under their acronyms (such as PETE, LDPE, PVC, PP and HDPE) requires a different chemical process.
That's why many household recycling programs ask residents to sort their plastics – and why communities that let people put recyclables of all types in one bin use people and machines to sort them out after their collection.
Sorting will not be easy with the plastic in the ocean. All types of plastic are mixed and some have been degraded chemically and physically by the action of the sun and waves. Much of it is now in tiny pieces called microplastics, hanging just beneath the surface. The first difficulty, but by no means the last, will be to sort out all that plastic – plus algae, barnacles and other marine species that may have attached to floating debris.
Recycling or recycling?
Ocean Cleanup is working on the best way to reprocess and mark the collected material, hoping that a buoyant market will emerge for its single source product. While the company's engineers and researchers can find a way to sort everything, there are physical limitations to the utility of the collected plastic.
Recycling involves grinding materials into very small pieces before melting and reforming them. An inevitable part of this process is that every time the plastic is recycled, its polymers – the long chemical sequences that provide its structure – become shorter.
In general, lighter and more flexible types of plastic can only be recycled in denser, harder materials, unless large amounts of virgin virgin plastic are added to the mix. After one or two cycles of recycling, the possibilities of reuse become very limited. At this point, the "recycled" plastic material is transformed into textiles, car bumpers or plastic timber, none of which are found elsewhere than in the landfill. Plastic becomes garbage.
Plastic Composting
And if there was a way to make sure the plastic was truly recyclable in the long run? Most bacteria can not degrade plastics because polymers contain strong carbon-carbon chemical bonds different from all that bacteria have evolved alongside nature. Fortunately, having been in the environment with plastics thrown away by humans for several decades, bacteria seem to be evolving to utilize this synthetic raw material that permeates modern life.
In 2016, a team of biologists and materials specialists discovered a bacterium that could consume the type of plastic used in beverage bottles. The bacterium transforms PET plastic into more basic substances that can be turned into virgin plastics. After identifying the key enzyme in the plastic digestion process of the bacteria, the research team then deliberately designed the enzyme to make it more effective. One researcher stated that the engineering work had managed to "outperform".
At this point, advances only work in laboratory conditions and on one of seven types of plastics. But the idea of going beyond the natural evolution is where the ear of an environmental philosopher goes on alert.
Synthetic enzymes and bacteria
The discovery of the plastic-eating bacteria and its enzyme took a long time to monitor, wait and test. Evolution is not always fast. The results suggest the possibility of discovering additional enzymes that work with other plastics. But they also raise the possibility of taking things in hand and designing new enzymes and microbes.
Already, completely artificial proteins encoded by synthetically constructed genes act as artificial enzymes and catalyze reactions in cells. One researcher says, "We can develop proteins – it usually takes billions of years – in a few months." In other laboratories, synthetic genomes entirely composed of chemical flasks are now able to operate bacterial cells. It is thought that fully synthetic cells (genomes, metabolic processes, functional cellular structures, etc.) are only a decade away.
See also: A 7th grader built a submarine rover to save the oceans from microplastics
This new era of synthetic biology promises not only to change what organisms can do; it threatens to change what organisms really are. Bacteria will no longer simply be natural life forms; some, if not many, will be microbes specially designed to provide useful functions for humans, such as composting plastics. The border between life and the machine will become blurred.
The polluting plastics of the world's oceans must be cleaned. Bringing them to the ground would reinforce the fact that even on a global scale, it's impossible to throw garbage in the trash – it just goes elsewhere for a while. But people have to be very careful about the kind of technological solutions they use. I can not help but see the irony of trying to solve the very real problem of too many synthetic materials that litter the oceans by introducing billions of proteins or synthetic bacteria into the world. clean them.
This article was originally published on The Conversation by Christopher J. Preston. Read the original article here.
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