Sunday, April 19, 2009
Teen Decomposes Plastic Bag in Three Months
Plastic takes thousands of years to decompose -- but 16-year-old science fair contestant Daniel Burd made it happen in just three months.
The Waterloo, Ontario high school junior figured that something must make plastic degrade, even if it does take millennia, and that something was probably bacteria.
(Hey, at between one-half and 90 percent of Earth's biomass, bacteria's a pretty safe bet for any biological mystery.)
Burd mixed landfill dirt with yeast and tap water, then added ground plastic and let it stew. The plastic indeed decomposed more quickly than it would in nature; after experimenting with different temperatures and configurations, Burd isolated the microbial munchers. One came from the bacterial genus Pseudomonas, and the other from the genus Sphingomonas.
Burd says this should be easy on an industrial scale: all that's needed is a fermenter, a growth medium and plastic, and the bacteria themselves provide most of the energy by producing heat as they eat. The only waste is water and a bit of carbon dioxide.
The Painting is by Henri Rousseau