A marine fungus has been discovered that is capable of decomposing polyethylene plastic, but only if it has been previously exposed to ultraviolet radiation from sunlight. This information has been published by NIOZ researchers and others in the scientific journal Science of the Total Environment. Scientists expect other plastic-degrading fungi to inhabit the deep ocean.
Discovery of the marine fungus
The fungus Parengyodontium album, which coexists with other marine microbes in thin layers of plastic debris, has shown the ability to break down polyethylene (PE) particles, the most common plastic in the ocean.
[post_relacionado]Researchers from the Royal Netherlands Institute of Marine Research (NIOZ) together with colleagues from the Utrecht University the Ocean Cleanup Foundation and several European research institutes, discovered this phenomenon. This fungus joins a very small list of marine fungi with the capacity to degrade plastics, of which only four species were known until now.
How does this marine fungus degrade plastic?
The research team has meticulously followed the plastic degradation process. Scientists collected plastic trash in critical areas of the North Pacific Ocean and isolated the marine fungus by culturing it in the laboratory with plastics containing labeled carbon. Annika Vaksmaa, lead author of the study, explained that these carbon isotopes allow carbon to be traced through the food chain. This method has allowed them to accurately quantify the degradation process.
Vaksmaa was enthusiastic about this scientific breakthrough, noting that they can measure the process of PE degradation by P. album, which occurs at a rate of 0.05% per day. In addition, they observed that the fungus converts most of the carbon in the EP into carbon dioxide, a greenhouse gas whose release in this case is similar to that of human respiration, so it does not represent a problem.
Marine fungus and the influence of sunlight on plastics
The research revealed that sunlight is essential for the fungus to use PE as an energy source. Under laboratory conditions, P. album only decomposes PE that has been exposed to ultraviolet light for a period of time. This means that in the ocean, the fungus can only degrade floating plastics near the surface. Although ultraviolet light was already known to break down plastic mechanically, this study shows that it also facilitates its biological decomposition by marine fungi.
Since many plastics sink before being exposed to sunlight, P. album cannot degrade them all. Vaksmaa is confident that there are other as yet unidentified fungi that could also degrade plastics in the deep ocean. With a great diversity of marine fungi, it is likely that more species are contributing to this process, although many questions remain about the degradation of degradation in the ocean .
Urgent need for plastic degrading organisms
The need to find organisms that degrade plastic is urgent. More than 400 billion kg of plastic are produced each year, an amount that is expected to triple by 2060. Much of this waste ends up in the sea, from the poles to the tropics, accumulating on ocean surfaces and in the ocean depths.
Vaksmaa points out that huge amounts of plastic are trapped in subtropical gyres, with around 80 million kg of floating plastic accumulated in the North Pacific subtropical gyre alone, one of the world’s six major gyres.
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Source: nioznl
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