Enzymex calculator11/6/2022 These two chemicals are the building blocks of PET, so Ideonella sakaiensis 201-F6 can completely reverse the manufacturing process that made PET. A second enzyme called MHETase then goes to work, producing ethylene glycol and terephthalic acid. The first is a PETase that breaks the long PET molecules down into smaller molecules called MHET. Ideonella sak a iensis 201-F6 produces two unique enzymes. For example, our saliva contains an enzyme called amylase that breaks up the long molecules of starch found in foods such as bread. They are crucial to life: our digestive system relies on enzymes to break down the complex chemicals in food into simpler ones that our bodies can absorb and use. Enzymes are complex molecules that can speed up chemical reactions. The key to this ability was a pair of enzymes made by the bacteria. In 2017, China banned trade in most plastic waste, putting pressure on the EU and US to find new ways to deal with the issue. Not only that: Oda’s team reported that the bacterium could use PET as its main source of nutrients, degrading the PET in the process.Ī Chinese labourer sorts plastic bottles for recycling, 2015. This microbe could grow on pieces of PET. It found a new strain of bacterium, called Ideonella sakaiensis 201-F6. Oda’s team took samples of sediment and wastewater that were contaminated with PET, and screened them for micro-organisms that could grow on the plastic. The chemical bonds in PET chains are strong, so it is long-lasting – exactly what you do not want in a single-use plastic. These are assembled from smaller molecules strung together into chains. Like all plastics, PET is a material made up of long string-like molecules. Oda’s team visited a recycling site that focused on items made of polyethylene terephthalate (PET), a clear plastic that is used to make clothing fibres and drinks bottles. In 2016 researchers led by microbiologist Kohei Oda of the Kyoto Institute of Technology in Japan reported a surprise discovery. But we do need a revolution in how we handle plastics, and this is where the micro-organisms come in. For example, plastic bottles are far lighter than glass ones, so transporting them requires less energy and releases a smaller amount of greenhouse gases. The solution is not to stop using plastics altogether, because they are incredibly useful. A 2021 report found that the US plastics industry alone releases 232m tonnes of greenhouse gases every year, the equivalent of 116 coal-fired power plants. Plastic manufacturing also releases greenhouse gases that contribute to global warming. Making plastic requires extracting fossil fuels such as oil from the ground, with all the pollution risks that entails. That does not sound so bad, but a lot of it is single-use plastic, which is inherently wasteful. “Over time we really don’t know what effects these have,” says Tiffany M Ramos of Roskilde University in Denmark. As well as the dangers of the plastics themselves, they contain a lot of additives that leach out into the water. Despite the popular image, only a small fraction of this ends up in the ocean – but the seas may still be absorbing more than 10m tonnes of plastic every year. In 2016 the world generated 242m tonnes of plastic waste, according to the World Bank. Photograph: Ernesto Benavides/AFP/Getty ImagesĪ huge fraction of this goes to waste. Pictured below, volunteers collect plastic rubbish from a beach in Lima, Peru. In 2016, the world produced 242m tonnes of plastic waste.
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