My last blog was on how to create bioplastic or biodegradable plastic from banana peels. A very innovative , cheap and simple technique for a very complex and serious problem.
But what should we do of the plastic that has been piling for the last many centuries.Science has the solution for everything, or I believe so.
Scientists have discovered bacteria and worms that have the capability of feeding on plastic. Plastic are long chain polymers that have repeating units of molecules that don’t dissolve in water. Which means that they take a very long time to degrade. With only 9 % of the total plastic being recycled, all life forms on earth are at threat of being intoxicated by the amount of plastic being dumped as trash.
Ideonella sakaiensis is the bacteria that has the capability of feeding on the carbons present in the plastic.These bacteria can digest the plastic used to make single use drink bottles, polyethylene teraphthalate(PET).
It secretes an enzyme PETase that speeds up the chemical reaction by breaking down the ester bond in PET,leaving smaller molecules that could easily be absorbed by the bacteria.The carbon in these smaller molecules is used as a food source by the bacteria.
Ideonella sakaiensis is a Gram- negative rod shaped bacteria that doesn’t form spores.A wild type bacterium is able to break down a thin film(0.2 mm) of PET in approximately 6 weeks. Because the commercially prepared synthetic PET plastic is highly crystalline scientists can adopt techniques to make these bacterium more effective.
Exiguobacterium sibiricum DR11 & Exiguobacterium undae DR14
Exiguobacterium sibiricum strain DR11 and Exiguobacterium undae strain DR14 are two strains of bacteria that were recently discovered by researchers in Greater Noida, Utter Pradesh.
These bacterial strains help to degrade polystyrene, which is a key component of single use plastic such as disposable cups, toys, packaging material etc.They on coming in contact with polystyrene plastic release enzyme that help in hydrolyzing the polystyrene into smaller molecule and create biofilms using up the carbon in the plastic as an energy source.
A wax worm , caterpillar that is usually seen munching on bee combs and are used as bait in fishing are now the stars of the show. These worms are now found to be feeding on plastic bags.
These worms were accidentally discovered by Scientist Federica Bertocchini of the Institute of Biomedicine and Biotechnology of Cantabria in Spain .
While she was cleaning a wax worm manifestation, she cleaned the area and kept a worms in plastic bag. After some time she saw that the worms had escaped the bag by chewing holes into them.
To make sure that these worms were not just shredding the plastic and actually eating them, the scientists pureed the plastic and then the worms were placed in the puree. They noticed a 13 % decrease in the plastic content.
On further examination of the rest of the content they found ethylene glycol residues, confirming polyethylene degradation. But using these worms on landfills to degrade plastic is not possible as they will not be able to survive in zero-oxygen climate that a landfill creates. Further studies and researches in this field can maybe help us find an enzyme that can help degrade the plastic.
Nature gives us many options to survive, It just depends on how much we value it. These bacteria, worms and fungi can truly be revolutionary in our efforts of coping with the plastic pollution. In 2011, researchers found a fungus that could erode polyurethane, another common plastic piling up in trash heaps and oceans globally.
Aspergillus tubingensis is a fungi that can eat plastic. It can degarde polyester polyurethane (PU) .
PU plastic is used in fridge insulation and synthetic leather products.It secrets enzymes that can degrade the plastic polymers into smaller molecules. It also mechanically breaks down the plastic with the help of its strong mycelia.
I hope that we are soon able to biodegrade the plastic that has heaped on our planet with the help of these organisms. Otherwise we may have serious health issues as the level of plastic in our food chain increases.