A novel way by which plastic bags decompose in months

09-Jul-08

Landfill-clogging plastic bags that take 20 to 1,000 years to decompose, could now break down in barely few months. Burd, An Ontario high school student has discovered a way to break down plastic in a few months. His hypothesis was that if plastic bags do eventually break down, it should be possible to isolate and concentrate the micro-organism responsible for the decomposition, thus speeding up the process. To test his hypothesis, he took a few soil samples from a local landfill and mixed them with polyethylene, the substance used to make plastic bags, as well as a solution to encourage bacterial growth. After concentrating the solution several times and incubating it for 12 weeks, he took the resulting bacterial culture and tested it on strips of polyethylene. After six weeks, the strips had lost more than 17% of their weight compared to a set of control strips. Burd concluded that a combination of two types of bacteria - Sphingomonas and Pseudomonas - was most effective at breaking down the polyethylene. After isolating these two bacteria, combining them with some sodium acetate and incubating the solution at 37 C, Burd was able to degrade the plastic by 43% in six weeks.