Chinese scientists claim to have discovered a strain of marine bacteria capable of degrading polythene, one of the most common plastics on the planet and a major source of contamination in the world’s oceans.
Although bacteria’s ability to consume plastic is well established in the scientific community, the research conducted by the Chinese Academy of Sciences’ Institute of Oceanology in Qingdao, Shandong Province, is the first to create a direct connection to polythene (PE).Sun Chaomin led a team that discovered a combination of bacteria that could break down not only polyethylene terephthalate (PET), which is used to make bottles, but also polythene, which is used to make bags, according to the report, which was published in the Journal of Hazardous Materials on April 23.
“Compared to the extensive studies into PET-degrading bacteria and enzymes, research into PE degradation lags well behind,” the researchers said.
The researchers said they introduced bacteria to polythene and polyethylene terephthalate samples and found that a specific combination of three bacteria was causing “obvious harm” to the polythene film, including “numerous heavy cracks and deep holes,” after repeated tests.Every year, approximately five million tonnes of plastic are poured into seas and oceans, and scientists are eager to find an environmentally sustainable way to dispose of it.
Plastic contamination kills about one million birds and 10,000 marine animals per year, according to the report, and PE and PET are among the worst offenders.
Despite the fact that scientists have identified over 430 microorganisms capable of degrading various types of plastics, Wolfgang Streit, a microbiology and biotechnology professor at the University of Hamburg in Germany who was not involved in the Chinese research, said the findings were intriguing.
“[Scientists] have a good understanding of how PET is degraded. We have enzymes for PET. But for PE, there is not a single enzyme known that degrades it,” he said.
The degradation abilities of the bacteria mix found by Sun and his team were the “best I have ever seen,” he said, but he cautioned that more research was required.
“By simply having a bacterial community that degrades plastic … it is not easy to define the exact bacteria and enzyme that does [the work],” he said. “That is another couple of years’ work to come down to that.”
More science, better legislation, and corporate responsibility are all needed, according to Douglas Woodring, the founder and managing director of Ocean Recovery Alliance, a Hong Kong and US-based environmental organization.
“While I am not dismissing the new discovery, we should not be overexcited and put all our hope on one solution,” he said. “We have all of the technologies needed to resolve the plastic pollution crisis today, but they are not being used.”
PET, he said was “one of the easiest of all plastics to collect and recycle, yet we still hardly do it on a scale that matches the volumes of bottles put into our economies”.
According to Paul Zimmerman, chairman of Drink Without Waste, a Hong Kong-based plastic recycling project, the new results must also be considered logistically.
“Collecting plastic from the ocean is expensive. Unless you suggest that the bacteria is released in the ocean to eat the plastics up, but that creates a high risk of changing nature and unintended consequences,” he said.
Source: South China Morning Post