Bacteria capable of eating and digesting plastic

Laboratory experiments show that there is at least one species of bacteria with the ability to “eat and digest” plastic.

The research has been carried out by the international team of Maaike Goudriaan, from the Royal Netherlands Institute for Marine Research (NIOZ).

The bacteria in question are of the species Rhodococcus ruber.

Based on a model with plastic in artificial seawater in a laboratory, Goudriaan and his colleagues have calculated that bacteria can break down about 1 percent of the plastic supplied to them each year. Decomposition releases carbon dioxide (CO2) and other substances that are not toxic.

It should be made clear, as Goudriaan emphasizes, that this is by no means a solution to the problem of plastic debris accumulating in the oceans. What the study reveals is where a part of the plastic that disappears in the sea ends up.

Goudriaan had a special plastic made for these experiments, with a different form of carbon, specifically the carbon-13 isotope.

When he fed the plastic to bacteria after previously treating it with “sunlight” (an ultraviolet lamp) in a bottle of simulated seawater, he observed that this special version of carbon appeared as carbon dioxide (CO2) above the surface. Water.

Plastic particles that measure around 2 millimeters. (Photo: NIOZ. CC BY)

The ultraviolet light treatment was necessary because sunlight is known to partially break down plastic into chunks small enough to be easily consumed by bacteria.

The results of this pioneering study therefore show that Rhodococcus ruber bacteria digest plastic, leaving CO2 and other substances in their place.

It was already known that bacteria of this species can form a biofilm on plastic. It had also been verified that the plastic disappears under this biofilm. But now Goudriaan and his colleagues have shown that bacteria actually digest plastic.

The study is titled “A stable isotope assay with 13C-labeled polyethylene to investigate plastic mineralization mediated by Rhodococcus ruber”. And it has been published in the academic journal Marine Pollution Bulletin. (Font: NCYT by Amazings)