Wax Worm Caterpillar Will Eat Plastic Shopping Bags: New Solution to Plastic Waste?

Date: April 24, 2017
Source: Cell Press
Summary: Generally speaking, plastic is incredibly resistant to breaking down. That's certainly true of the trillion polyethylene plastic bags that people use each and every year. But researchers may be on track to find a solution to plastic waste. The key is a caterpillar commonly known as a wax worm.

This image shows a wax worm chewing a hole through plastic. Polyethylene debris can be seen attached to the caterpillar.
Credit: Federica Bertocchini, Paolo Bombelli, and Chris Howe

Generally speaking, plastic is incredibly resistant to breaking down. That's certainly true of the trillion polyethylene plastic bags that people use each and every year. But researchers reporting in Current Biology on April 24 may be on track to find a solution to plastic waste. The key is a caterpillar commonly known as a wax worm.

"We have found that the larva of a common insect, Galleria mellonella, is able to biodegrade one of the toughest, most resilient, and most used plastics: polyethylene," says Federica Bertocchini of the Institute of Biomedicine and Biotechnology of Cantabria in Spain. A previous study (doi: 10.1021/es504038a) has shown that Plodia interpunctella wax worms, the larvae of dian mealmoths, can also digest plastic.

Bertocchini and her colleagues made the discovery quite by accident, after noticing that plastic bags containing wax worms quickly became riddled with holes. Further study showed that the worms can do damage to a plastic bag in less than an hour.

After 12 hours, all that munching of plastic leads to an obvious reduction in plastic mass. The researchers showed that the wax worms were not only ingesting the plastic, they were also chemically transforming the polyethylene into ethylene glycol. This is suspected to be the case in Plodia interpunctella as well.

Although wax worms wouldn't normally eat plastic, the researchers suspect that their ability is a byproduct of their natural habits. Wax moths lay their eggs inside beehives. The worms hatch and grow on beeswax, which is composed of a highly diverse mixture of lipid compounds. The researchers say the molecular details of wax biodegradation require further investigation, but it's likely that digesting beeswax and polyethylene involves breaking down similar types of chemical bonds.

"Wax is a polymer, a sort of 'natural plastic,' and has a chemical structure not dissimilar to polyethylene," Bertocchini says.

As the molecular details of the process become known, the researchers say it could be used to devise a biotechnological solution to managing polyethylene waste. They'll continue to explore the process in search of such a strategy.

"We are planning to implement this finding into a viable way to get rid of plastic waste, working towards a solution to save our oceans, rivers, and all the environment from the unavoidable consequences of plastic accumulation," Bertocchini says. "However," she adds, "we should not feel justified to dump polyethylene deliberately in our environment just because we now know how to bio-degrade it."

Journal Reference:
Bombelli et al. Polyethylene bio-degradation by caterpillars of the wax moth Galleria mellonella. Current Biology, 2017 DOI: 10.1016/j.cub.2017.02.060

Story Source:
Cell Press. "Wax worm caterpillar will eat plastic shopping bags: New solution to plastic waste?." ScienceDaily. ScienceDaily, 24 April 2017. www.sciencedaily.com/releases/2017/04/170424141338.htm.

Gut Bacteria from a Worm Can Degrade Plastic

Date: December 3, 2014

Source: American Chemical Society

Summary: Plastic is well-known for sticking around in the environment for years without breaking down, contributing significantly to litter and landfills. But scientists have now discovered that bacteria from the guts of a worm known to munch on food packaging can degrade polyethylene, the most common plastic.The finding could lead to new ways to help get rid of the otherwise persistent waste, the scientists say.

Some bacteria from the guts of waxworms could help us eliminate plastic trash.
Credit: ACS

Plastic is well-known for sticking around in the environment for years without breaking down, contributing significantly to litter and landfills. But scientists have now discovered that bacteria from the guts of a worm known to munch on food packaging can degrade polyethylene, the most common plastic. Reported in the ACS journal Environmental Science & Technology, the finding could lead to new ways to help get rid of the otherwise persistent waste, the scientists say.

Jun Yang and colleagues point out that the global plastics industry churns out about 140 million tons of polyethylene every year. Much of it goes into the bags, bottles and boxes that many of us use regularly -- and then throw out. Scientists have been trying to figure out for years how to make this plastic trash go away. Some of the most recent studies have tried siccing bacteria on plastic to degrade it, but these required first exposing the plastic to light or heat. Yang's team wanted to find bacteria that could degrade polyethylene in one step.

The researchers turned to a plastic-eating moth larva, known as a waxworm. They found that at least two strains of the waxworm's gut microbes could degrade polyethylene without a pretreatment step. They say the results point toward a new, more direct way to biodegrade plastic.

The authors acknowledge funding from the National Natural Science Foundation of China, the National Basic Research Program of China and the Shenzhen Key Laboratory of Bioenergy.

Story Source: The above story is based on materials provided by American Chemical Society.

National Academies – Report on Sustainable Reuse and Recycling

Energy and Water Considerations for the Sustainable Reuse and Recycling of Materials

In September 2013, the STS Program convened a meeting of research leaders and technical experts in private industry as well as representatives from government and academia to examine the energy-water considerations of material reuse and recycling. The meeting examined the data and research needs for assessing the energy-water linkages with the reuse and recycling of waste streams and materials; the technologies and approaches needed to further recycling and reuse strategies; and how the public and private sectors can leverage the efforts of key stakeholders to further technological development, innovation, data collection, and research. This meeting summary synthesizes the discussions held during the event.

Source: For more information, go to http://sites.nationalacademies.org/PGA/sustainability/PGA_084717.

Click here to download the meeting summary