downtoearth-subscribe

Plastic busters

scientists in Sri Lanka have found a new way to safely dispose plastic materials. They enlisted the services of a bacterium and a fungus that feed on hydrocarbons to break down polymer chains in polythene products.

An estimated 60 million tonnes of polyethylene are produced annually the world over. But polymers have been an environmental concern as they take thousands of years to completely decompose. The use of microbes for hastening plastic degradation has been tried earlier too, but never so effectively.

The scientists from Institute of Fundamental Studies and Post Graduate Institute of Science and University of Peradeniya analysed microbes that grow on different types of polythene products buried in soil for 2-4 years. Out of 25 bacteria and six fungi, the bacterium, Penicillium frequentans, and the fungus, Bacillus mycoides, were found to be the most effective.

In their experiments, the scientists found that when the microbes work in tandem, better results are obtained. In 21 days, the weight of polythene pieces, put in a test tube with both the microbes present, reduced by 7 per cent as against 0.5 per cent reduction observed in the test tube in which only the bacteria was present and no change when only the fungus was present. The findings appeared in the January 10 issue of Current Science (Vol 90, No1).