Scientists from Nanyang Technological University (NTU) Singapore developed an artificial worm gut capable of breaking down plastics. This offers hope for a nature-inspired way to address the problem of global plastic pollution.

worm
(Photo: Pexels / Karolina Grabowska)

Artificial Worm Gut That Could Break Down Plastics

By cultivating the microbes in the worms' guts and feeding them plastics, researchers showed a unique way to accelerate the biodegradation of plastics.

Studies have revealed that the Zophobas atratus worm, the larvae of darkling beetles known as superworms due to their nutritional value and are commonly sold as pet food, can survive on a plastic diet. This is because its gut has bacteria capable of breaking down common plastic types. However, their use when it comes to plastic processing has been considered impractical because of the slow feeding rate and worm maintenance rigors.

The scientists have now discovered how these challenges can be overcome. They found that isolating the gut bacteria of the worm and using them to do the job can be done. This can be executed without the need to breed worms on a large scale.

Efforts were documented in the "Establishment of plastic-associated microbial community from superworm gut microbiome" study.

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The Making of the Artificial Worm Gut

To come up with this approach, the researchers fed three superworm groups with different diets of plastic, including polystyrene (PS), polypropylene (PP), and high-density polyethylene (HDPE). This was done in more than 30 days. The control group, on the other hand, received an oatmeal diet.

Such plastics were chosen because they are the most common worldwide. These plastics are utilized in everyday items, such as detergent bottles and food boxes.

After feeding the worms plastic, researchers extracted their gut microbiomes and incubated them in flasks with synthetic nutrients and various plastic types. This led to the formation of an artificial worm gut. In six weeks, the microbiomes were left to grow at room temperature within these flasks.

The researchers observed that compared to the control group, the flasks with the gut microbiomes from the worms fed with plastics had a notable increase in bacteria that degraded plastic. Moreover, the communities of microbes colonizing the plastics within the flasks were simpler and more tailored to specific plastic types than the microbes found on plastics that the worms were directly fed. When such communities are more targeted and straightforward, this implies the potential to have more efficient plastic degradation in actual applications.

Dr. Liu Yinan, the study's first author and a Research Fellow at NTU's School of Civil and Environmental Engineering (CEE) and the Singapore Center for Environmental Life Sciences ENgineering (SCELSE), explain that the study serves as the first reported successful attempt to make plastic-connected communities of bacteria from gut microbiomes of worms that have been fed with plastic. Exposing the microbiomes to certain conditions increased the abundance of plastic-degrading bacteria in the artificial worm gut. This suggests that the approach is replicable and stable at scale.

The scientists want to know more about how the bacteria within the gut break down the plastics at a molecular scale. Knowing such a mechanism would aid scientists in efficiently engineering bacterial communities that degrade plastics.

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