BRITAIN – Brunel University researchers in London are investigating if bacteria found in polystyrene trash could be utilized to degrade polyester fibers.
This study is yet another illustration of how researchers are discovering that bacteria and other microbes seem to be acquiring biological processes to degrade manmade polymers in the environment.
The research team enriched polystyrene waste from an Irish beach to isolate microorganisms shown to contain three enzymes that could aid in the degradation of plastic fibers, as described in the study “Enrichment of native plastic – associated biofilm communities to enhance polyester degrading activity.”
To identify communities that had increased plastic degrading skills after simply having the waste plastic as a carbon source, the scientists gathered native bacterial communities from waste plastic and then conducted an enrichment experiment.
They noticed a shift in the makeup of the community and discovered a strain of bacteria called Pseudomonas stutzeri that has three well-known enzymes that may be involved in the breakdown of polyester.
Dr. Ronan McCarthy, the report’s author, explained: “Many of the known enzymes and microorganisms that degrade plastic have low efficiency by nature, so we need to choose organisms with higher efficiency or modify the enzymes to operate better.
“Through our enrichment experiment, we discovered that native plastic waste communities can be enhanced for populations that have better degrading activity.
The enrichment experiment settings can be adjusted to optimize the separation of bacteria that are suitable for commercial batch culture. This method can be used with any waste plastic. Three potential enzymes that might be involved in the degradation of polyester were also found.
He continued that the objective was to identify and isolate natural bacterial communities from waste plastic. The researchers discovered that most bacteria were encouraged to develop biofilm colonies on expanded polystyrene in the lab.
According to the paper, this could be a result of the fact that expanded polystyrene has several air holes and floats in the water, which enables a lot of bacteria to adhere to it and stay shielded from the surroundings.
The enhanced community was collected and examined for its capacity to degrade plastic after the enrichment experiment. They first contrasted the capacity of the two communities to break down polycaprolactone (PCL), a low melting point polyester.
Seven of the enhanced communities were able to degrade PCL and did so more effectively than the original community; in the majority of cases, the original community showed no indication that it could do so.
Future research might concentrate on applying the same enrichment experiment to various samples of plastic garbage to find new bacterial species that can break down various kinds of plastic.
“It provides a potentially fruitful method of enhancing species that can flourish on plastic trash. The more bacteria we discover that can break down a wider variety of plastic, the more choices we have for using microorganisms in industrial settings to break down plastic waste, said Dr. McCarthy.
