Scientists find bacteria and fungi that eat plastic waste
A diverse microbiome of bacteria and plastic-degrading fungi lives in salt marshes on the coast of Jiangsu, China. It was identified by an international team of scientists who counted 55 bacterial and 184 fungal strains that are able to break down a biodegradable polyester called polycaprolactone (PCL), often used in polyurethane production, a press release from the Royal Botanic Gardens, Kew, said.
“The growing body of scientific evidence sheds light on the environmental potential for plastic degradation that needs to be unlocked,” Dr. Irina Druzhinina, senior research leader in Fungal Diversity and Systematics at Royal Botanic Gardens (RBG) Kew, told EcoWatch in an email.
The study, “The distinct plastisphere microbiome in the terrestrial-marine ecotone is a reservoir for putative degraders of petroleum-based polymers,” was published in the Journal of Hazardous Materials.
The scientists took samples of the plastic-degrading microorganisms from Dafeng, near China’s Yellow Sea Coast and a UNESCO-protected site, in May of 2021. A terrestrial plastisphere — a relatively new term to terrestrial ecology — was confirmed. The microbiome of the coastal plastic debris was also different from the soil that surrounded it.
“The initial exploration of microbial biofilms on plastic waste primarily focused on the marine environment. In our study, we chose to examine the marine-terrestrial ecotone (the borderline ecosystem) due to its unique characteristics, which make it somewhat reminiscent of the marine environment while being significantly richer in carbon and other nutrients. Delving into these highly diverse microbiomes was a bold decision, but it proved rewarding,” Druzhinina told EcoWatch.
“Our sampling strategy deliberately avoided the most heavily polluted coastal areas. Instead, we aimed to observe the natural behavior of microbiomes in colonizing plastic debris. The DaFeng natural wetlands in Yancheng, included in the UNESCO World Heritage List, became our chosen location. This area is home to a diverse array of bird species, including the extremely rare Chinese crested-tern (Thalasseus bernsteini) with its distinctive yellow beak, as well as the stunning and endangered red-crowned cranes (Grus japonensis).”
The extent of the plastic pollution problem has steadily increased since the 1970s. Each year, 400 million tonnes of plastic waste is produced, according to the United Nations Environment Programme, and increasingly more often scientists are looking to bacteria, fungi and other microorganisms to help deal with it
Thus far, 436 species of bacteria and fungi have been discovered that break down plastic. The scientists from Kew and their partners are hopeful that their latest discovery may lead to the designing of efficient enzymes to degrade plastic waste biologically.
A “microbial reef” for bacteria and fungi has been created by the plastics that have ended up in aquatic ecosystems because of their hydrophobic surface and longevity. And with some biodegradable plastics, microbes are provided with a carbon — or food — source.
Fifty plastic waste samples were collected by the researchers at Dafeng from seven types of petroleum-based polymers: polyurethane (PU), polypropylene (PP), polyvinyl chloride (PVC), expanded polystyrene (EPS), polyethylene terephthalate (PET), polyethylene (PE) and polyamide (PA).
Source: World Economic Forum
