Alex Wilkins is a writer.

A giant pile of plastic waste

Most recycling methods only work on one type of plastic, which makes it difficult to break down.

There is a photo of neenawat khenyothaa.

A mix of plastic rubbish has been converted into a useful product using a combination of catalysts and engineeredbacteria. The technique could be used to make other types of plastic.

It is difficult to design facilities that can cope with a mixture of plastic waste because processes that convert plastic waste into useful chemicals tend to focus only on one plastic.

Beckham and his colleagues at the National Renewable Energy Laboratory in Colorado have designed a two-step process that uses catalysts and a modified soil bacterium to treat plastic waste.

Polyhydroxyalkanoates, which are frequently used in medical applications such as sutures or in repairing tendons, were transformed by the group.

One component of the process is borrowed from a common industrial method. Oxygen and chemical catalysts are used to break down carbon bonds in the mixed plastic waste.

Beckham says that step one is like a big hammer, and that you just take oxygen and chemical catalysts to make bioavailable intermediates.

Beckham and his team engineered the bacterium to produce polyhydroxyalkanoates in this study, but it should be possible to get it to produce other more widely used products. They want to extend the method to cope with a greater variety of plastic.

Beckham believes that if the organisms can eat or consume the oxygenated intermediates, then they could make anything.

A new recycling chain for mixed plastic waste could be formed by combining chemical breakdown and biological conversion.

He says that the idea of pretreating the polymers to get a diverse set of feedstocks is important.

The process needs to be shown to make economic sense in the real world in order for it to work.

The journal is called Science.

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