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.

Unique Waste Cleanup for Rural Areas Developed

Source: Washington State University
Summary: A unique method has been developed to use microbes buried in pond sediment to power waste cleanup in rural areas. The first microbe-powered, self-sustaining wastewater treatment system could lead to an inexpensive and quick way to clean up waste from large farming operations and rural sewage treatment plants while reducing pollution.

Washington State University researchers have developed a unique method to use microbes buried in pond sediment to power waste cleanup in rural areas.

The first microbe-powered, self-sustaining wastewater treatment system could lead to an inexpensive and quick way to clean up waste from large farming operations and rural sewage treatment plants while reducing pollution.

Professor Haluk Beyenal and graduate student Timothy Ewing in the Voiland College of Engineering and Architecture discuss the system in the online edition of Journal of Power Sources and have filed for a patent.

Cutting Greenhouse Gases

Traditionally, waste from dairy farms in rural areas is placed in a series of ponds to be eaten by bacteria, generating carbon dioxide and methane pollution, until the waste is safely treated. In urban areas with larger infrastructure, electrically powered aerators mix water in the ponds, allowing for the waste to be cleaned faster and with fewer harmful emissions.

As much as 5 percent of energy used in the U.S. goes for waste water treatment, said Beyenal. Most rural communities and farmers, meanwhile, can't afford the cleaner, electrically powered aerators.

Microbial fuel cells use biological reactions from microbes in water to create electricity. The WSU researchers developed a microbial fuel cell that does the work of the aerator, using only the power of microbes in the sewage lagoons to generate electricity.

The researchers created favorable conditions for growth of microbes that are able to naturally generate electrons as part of their metabolic processes. The microbes were able to successfully power aerators in the lab for more than a year, and the researchers are hoping to test a full-scale pilot for eventual commercialization.

Hope for Dairies

The researchers believe that the microbial fuel cell technology is on the cusp of providing useful power solutions for communities.

"Everyone is looking to improve dairies to keep them in business and to keep these family businesses going,'' said Ewing.

The technology could also be used in underdeveloped countries to more effectively clean polluted water: "This is the first step towards sustainable wastewater treatment,'' Ewing said.

Beyenal has been conducting research for several years on microbial fuel cells for low-power electronic devices, particularly for use in remote areas or underwater where using batteries is challenging. Last year, he and his graduate students used the microbes to power lights for a holiday tree.

Story Source: Washington State University. "Unique waste cleanup for rural areas developed." ScienceDaily. ScienceDaily, 18 September 2014. www.sciencedaily.com/releases/2014/09/140918210136.htm.