Bacteria finds a way to help recycle plastics

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Plastic munching enzymes from a bacterium

Recycling plastics using enzymes developed from bacteria is a game changer. Some plastics can be recycled but each time you recycle it you lose quality. This new approach combines two plastic-munching enzymes developed by a bacterium. In 2016 a species of bacterium was discovered in a Japanese recycling plant. The bacterium had learned how to digest plastic. It caused a sensation at the time and has instigated a global effort to work out how it happened and to exploit it.

Plastic munching enzymes from a bacterium

Plastic munching enzymes from a bacterium. Image: Phys.org

The scientists realised that as plastic was a new product to nature there were no creatures on the planet that could use it as food. Evolution took its time in exploiting plastic. Nature discovered a biological niche. The scientists drilled down to what was happening and found that two enzymes working together called PETase and MEHTase degrades plastic into simpler chemicals. They decided to link the two enzymes together to create a super enzyme which dramatically speeded up the process. In fact there was a six-fold speed improvement compared to using the enzyme PETase alone.

As the enzymes broke down the polymers to individual building blocks they could then be recombined into true virgin plastic without using oil. This had great benefits. Prof McGeechan whose work is published in “Proceedings of the National Academy Of Sciences”, said “If you compare making a plastic bottle with enzyme monomers to digging up fossil fuels and transporting them all over the place, there’s a 70% energy saving”.

Mark Lorch from the University of Hull, who wasn’t involved in research, said, “..that nature will, eventually, be able to clean up our mess”.

Indeed, nature will find a way to clean up the mess made by humans. In this case bacteria may be saving the day. Clearly individual countries are unable to slow the production of plastic and minimise the careless way in which it finds its way into the oceans. Therefore, a way forward is to degrade the plastic into a usable product which can be transformed into high quality plastic once again. Let’s see some fishing ships fishing for plastic waste rather than fish! One day there may be more money in fishing for plastic and recycling it then fishing for marine wildlife. That’ll be the day.