Scientists have unearthed a group of extraordinary bacteria capable of feasting on plastic. This remarkable finding not only promises to tackle the pressing issue of pollution but could also hold great potential for economic growth, according to a recent study.
While previous enzymes used in industrial applications for plastic degradation required high temperatures above 30°C, the newly discovered cold-adapted microbes operate efficiently at lower temperatures, making them a cost-effective and environmentally friendly solution.
Plastic-digesting Bacteria
Researchers from the Swiss Federal Institute WSL embarked on a quest to explore the Alps and polar regions, known for their extreme conditions, in search of these unique microorganisms.
Their findings shed light on the remarkable plastic-digesting capabilities of these bacteria.
Lead author Dr. Joel Rüthi, a guest scientist at WSL, explained the significance of their discovery, stating, "Here we show that novel microbial taxa obtained from the 'plastisphere' of alpine and arctic soils were able to break down biodegradable plastics at 15°C. These organisms could help to reduce the costs and environmental burden of an enzymatic recycling process for plastic."
The team collected samples of bacteria and fungi from plastic debris in Greenland, Svalbard, and Switzerland, including litter obtained during the Swiss Arctic Project 2018.
Cultivating these isolated microbes in the laboratory, the researchers used advanced molecular techniques to identify the strains. Astonishingly, they discovered that 56% of the strains possessed the ability to digest plastic, although polyethylene remained resistant.
Among the most impressive performers were two uncharacterized fungal species, Neodevriesia and Lachnellula, which showcased the extraordinary capability to digest all tested plastics, excluding polyethylene.
Additionally, the study revealed that the plastic-digesting ability varied among strains depending on the culture medium.
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Evolutionary Origins
The evolutionary origins of this unique trait remain intriguing. Plastics have only been in existence since the 1950s, indicating that the ability to break them down was not a trait directly selected for by natural evolution.
Dr. Beat Frey, a senior scientist and group leader at WSL, provided insights into this phenomenon, stating, "Microbes have been shown to produce a wide variety of polymer-degrading enzymes involved in the break-down of plant cell walls."
"In particular, plant-pathogenic fungi are often reported to biodegrade polyesters because of their ability to produce cutinases, which target plastic polymers due to their resemblance to the plant polymer cutin."
Although the unearthing of these plastic-consuming bacteria is unquestionably a remarkable advancement, obstacles persist.
The scientists are still in the process of determining the ideal temperature range for the enzymes' effectiveness, but they have observed that the strains generally flourish within temperatures ranging from 4°C to 20°C, with an optimum temperature of approximately 15°C.
Further research is needed to identify the specific enzymes involved, optimize their production, and enhance their stability for large-scale applications.
The revelation of these plastic-digesting bacteria brings hope for a sustainable future where the global plastic waste problem can be effectively addressed.
The study's findings were published in Frontiers in Microbiology.
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