“Chinese scientists say they have identified a blend of marine bacteria that appears capable of breaking down polythene, one of the most ubiquitous plastics on the planet and source of much of the pollution in the world’s oceans.
While the plastic-eating qualities of bacteria are already well known to the scientific community, the research by the Institute of Oceanology, Chinese Academy of Sciences in Qingdao, east China’s Shandong province, is the first to establish a direct link to polythene (PE).
In the study, which was published in the Journal of Hazardous Materials on April 23, a team led by Sun Chaomin said they had discovered a combination of bacteria that was able to break down not only polyethylene terephthalate (PET) – from which bottles are made – but also polythene, which is used to make bags.
“Compared to the extensive studies into PET-degrading bacteria and enzymes, research into PE degradation lags well behind,” the researchers said.
The team said they added bacteria to samples of polythene and polyethylene terephthalate, and after repeated tests it became clear that a particular combination of three types of bacteria was causing “obvious damage” to the polythene film, including making “numerous heavy cracks and deep holes”.
About 5 million tonnes of plastic are dumped into seas and oceans every year and scientists are keen to find an environmentally friendly way to get rid of it.
According to the paper, plastic pollution is responsible for the deaths of about 1 million birds and 10,000 marine animals annually, and PE and PET are among the worst offenders.
While scientists have identified more than 430 microorganisms that can degrade different types of plastics, Wolfgang Streit, a microbiology and biotechnology professor at the University of Hamburg in Germany, who was not involved in the Chinese study, said the findings were interesting.
“[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 capabilities of the mix of bacteria Sun and his team identified were the “best I have ever seen”, he said, but cautioned that further study was needed.
“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.”…