More than 50 tons of plastic is produced globally each year which litters virtually every corner of the world and contributes to several environmental hazards. Fortunately, now it seems that we may have some source to clean this mess of ours.
Plastic i.e. Polyethylene terephthalate (PET) is the polymer which is extensively used for its remarkable characteristics, such as strength to weight ratio (light weight), shatter resistance, chemical resistance, and transmissivity. This polymer of ethylene glycol and terephthalate is moulded into bottles and containers and is commonly used all over the world. But apart from these desirable properties, its non-biodegradable nature makes natural degradation through biological processes impossible. It starts accumulating in our environment and results inplastic pollution that has negative impact on life at every level from marine to terrestrial and ultimately, to humans too. It puts chemical burden on environment by releasing toxic chemicals such as benzene, acetone, toluene, and trichloroethane. Thus plastics are a source of emission of poisonous gases and volatile compounds.
In addition to this chemical burden, plastic debris presents hazardous impact on the life of living beings. Phthalate found in plastic negatively affects the reproductive processes, impairs development, and acts as an endocrine disruptor.
Thankfully, there are some good environment-friendly bacteria that put an end to this undesirable property of such a widely used substance.
A team of Japanese scientists of Kyoto Institute of Technology, Matsugasaki, Kyoto, discovered bacteria that break down and metabolize plastic. They collected PET debris from PET bottle recycling site and screened the sample for micro-organisms. They found a mixture of bacteria that catabolizes PET film and converts the carbon present in PET into carbon dioxide. After testing the mixture, researchers isolated the bacterium that degrades and assimilates PET and named it Ideonella sakaiensis. The bacterium secretes certain enzymes which degrade the PET. After adhering to the PET surface, an enzyme PET hydrolase (PETase)acts upon PET to release intermediate compound Mono-(2-hydroxyethyl) terephthalate (MHET) which is acted upon by another enzyme MHETase to provide the bacterium with carbon and energy and eventually catabolize plastic into its monomers: ethylene glycol and terepthalic acid.
The researchers report that Ideonella sakaiensis could break down a thin film of PET in this way over the course of six weeks. The enzyme system can be manufactured by using genetically engineered bacteria to clean up the mess and eliminate world’s massive plastic problem that is otherwise impossible owing to its inert nature and chemical resistance.
This research has fuelled the excited speculation that one day we could get rid of this mess which we have been creating. Now, hopes are high that this new approach to plastic recycling and decontamination may alleviate plastic pollution to some degree.