Microbes in cow’s stomach can degrade plastic, study suggests
With the use of single-use plastics creating an ever-growing pollution problem, scientists are searching for ways to degrade the material, with research in recent years considering microorganisms, including bacteria and fungi, as a biological means of recycling plastic in an environmentally friendly way.
Researchers at the University of Natural Resources and Life Sciences in Vienna hypothesised that some of the microbes in the cow’s rumen, the largest compartment of a cow’s stomach, should be able to degrade polyesters, due to their diets. Cows consume a natural polyester produced by plants, called cutin, which can be found in peels of tomatoes and apples, Dr Doris Ribitsch, a senior scientist on the research team told Live Science.
The researchers examined the effect of liquid from the rumen on three types of polyesters by incubating each plastic for three days. It was tested on PET (a synthetic polymer often used in food packaging); PBAT (biodegradable plastic commonly used in compostable plastic bags); and PEF (a material derived from plant or vegetable sources). Each type was tested in both film and powder form.
The study, published in the journal Frontiers in Bioengineering and Biotechnology, found that all three plastics could be degraded by the microorganisms found in rumen, although they broke down PEF best. The plastic powders broke down quicker than plastic film.
The team analysed DNA from the liquid to identify which microbes were behind the degradation, finding that 98 per cent were bacteria.
The research could in turn allow scientists to identify the bacteria driving the material’s degradation and the enzymes they produce. They could then be genetically engineered and used in the recycling process.
Dr Ribitsch said the research team was also trying to find microbes that can consume more stubborn plastics such as polyethylene – and wonders if they could also possibly be found in the stomachs of cows. “Maybe we can find, in such huge communities, like in the rumen liquid, enzymes that can also degrade polypropylene and polyethylene,” she told Live Science.
At present, most of the UK’s plastic waste is burned or dumped, often after being shipped out to other countries. A Greenpeace investigation earlier this year found plastic bags and packaging from UK retailers and supermarkets dumped at sites across southern Turkey, leading the organisation to condemn British firms for dumping their waste abroad.
See more here: msn.com
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Peter F Gill
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Most plastics have been around for less than 100 years. For example nylon was discovered in 1932 by DuPont’s Wallace Carothers. It is to be expected that creatures in the natural world will evolve to include plastics in their diet. In the meantime pyrolysis or combustion with appropriate clean up of effluents is probably the best way of dealing with wastes.
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Mark Tapley
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There is no evolution. Cattle, goats, deer, camels etc. are ruminants with complex digestive systems with four stomachs. The fourth stomach is a fermentation chamber using microscopic animals to digest all the cellulose and roughage that other single stomach animals cannot. It is amusing that the so called vegans point to cattle as an example of the way we should eat, when humans have a comparitably simple digestive system similar to a dog. We are not designed (no evolution) to process large quantities of cellulose, fiber or grains.
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Mark Tapley
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Correction: 3rd stomach of the four. Then on to #4.
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Herb Rosr
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Why don’t they check the bacteria in goats? They seem to eat everything.
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Oldavid
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I suggest we look at the bacteria in termites. Those little fellas even eat plastic insulation on underground cables and motor car tyres if left undisturbed for long enough… at least the type of termites found in sub tropical Western Australia do.
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tom0mason
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As it often happens, especially when considering the long term destruction of plastics, man and his science is more than a country mile behind nature. Insects, slimes, and microbes have been consuming natural polymers for an exceedingly long time, why should these creatures not be able to ingest and consume man-made polymers?
Sure, man-made polymers will be a little more difficult but IMO the natural world will find a way as man-made plastics are simple chemically with reasonable high energy availability when broken-down. I predict that variants of natural insects, molds, bacteria, etc., will enter the naturally and come to the for worldwide as these plastics pile-up, and these microbes and creatures will be more than capable of digesting mankind’s wasted plastics.
Also I note that when I last went close to a landfill site most plastics (mostly plastic bags but also nylon and acrylic waste) were in what I can only call a state of decomposition.
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