Bacteria can use plastic waste as a food source, which is not as good as it seems: ScienceAlert

Bacteria can use plastic waste as a food source, which is not as good as it seems: ScienceAlert
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Plastic pollution is out of control. More every year 8 million tons some of the synthetic polymers enter the ocean and some sinks to the floorreturns to The coastor collects in the middlea significant part is not so easily calculated.

All this missing plastic is a mystery, but some researchers think hungry microbes are partly responsible.

Laboratory experiments have now shown that a species known as marine bacteria rhodococcus rubercan slowly break down and digest the prepared plastic polyethylene (PE).

Mainly used in packaging, PE is the most produced plastic in the world and it is not clear whether it is R. ruber If it eats this waste in the wild, a new study confirms that it can at least do that.

Previous studies they found strains R. ruber floating in dense cell films on marine plastic. Moreover, a preliminary study in 2006 he suggested plastic underneath R. ruber it was breaking down at a faster rate than normal.

A new study confirms that this is the case.

“This is the first time we have demonstrated that bacteria digest plastic into CO2 and other molecules in this way.” he says Maaike Goudriaan, a microbial ecologist from the Royal Netherlands Institute for Marine Research (NIOZ).

To mimic the natural ways plastic breaks down on the ocean surface, Goudriaan and his colleagues exposed plastic samples to artificial seawater and placed them in artificial seawater.

“The UV treatment was necessary because we already know that sunlight breaks the plastic down into bite-sized pieces for bacteria, in part.” explains Gudrian.

Next, the team introduced a strain R. ruber to the scene.

Measuring the level of an isotope of carbon released from decomposing plastic called carbon-13, the authors estimated that the polymers in their experiment decay at about 1.2 percent per year.

The team can’t be sure how much the UV lamp decomposed the plastic compared to microbial activity, but bacteria clearly played a role. After the experiment, bacterial samples showed fatty acid membranes enriched with carbon-13.

The rate of plastic degradation determined in the present study it is very slow is to completely solve the problem of plastic pollution in our oceans, but it also shows where some of the plastic that is missing from our planet is going.

“Our data show that sunlight could thus have destroyed a significant proportion of all floating plastics dumped into the oceans since the 1950s.” he says microbiologist Annalisa Delre.

After that, microbes could come in and digest some of the Sun’s remains.

There have been researchers since 2013 warned microbes multiplying on plastic patches in the ocean and forming a synthetic ecosystem known as the “plastisphere”.

There is even evidence that some of these microbial communities exist they adapt eating different types of plastic.

Previous studies have identified specific bacteria and fungi. on land and in the sea, looks like plastic food. But this knowledge can help us better recycle our waste Its other uses before ending up in the wild are controversial.

Some scientists have suggested releasing plastic food equivalents at pollution hotspots The Great Pacific Garbage Patch.

Others I’m not so sure that’s a good idea. engineered enzymes and bacteria breaking down plastic may sound like a great way to eliminate our waste, but some experts worry about unintended side effects on natural ecosystems and food webs.

After all, decomposing plastic isn’t necessarily a good thing. Microplastics are more difficult to clean than larger pieces, and these small residues can seep into food webs. For example, filter feeders can mistakenly capture small pieces of plastic before microbes.

One to learn In 2020, every seafood sample tested at a market in Australia contained microplastics.

This is what it does to human or animal health completely unknown.

“Prevention is better than cleaning” argue Gudriaan.

“And only we humans can do that.”

The study was published Marine Pollution Bulletin.

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