While thousands of insects and pests are evolving to resist the poisons we use against them, here is a bacteria that readily gobble up the pesticides, breaks them up and make them absolutely harmless.
The scientists at the Environmental Science Department of the University of Kerala have isolated a strain of bacteria that can completely degrade the pesticide, chlorpyriphos.
This finding is highly significant because the bacterium can be made use of in cleaning up the already contaminated soil. The pesticide residue in the soil can be degraded into substances that are totally benign.
This particular bacteria, identified by the scientists as Ochrobactrum thiophenivorans, finds chlorpyriphos a tasty meal, degrading it completely.
“Microbes capable of degrading pesticides, though very few in number, have been reported earlier. But is very rare to get a bacteria that completely degrades a pesticide,” said V Salom Gnana Thanga, head of the Department of Environmental Science, who conducted the study along with R Bindhiya, a research scholar.
Chlorpyrifos is a broad spectrum insecticide, a chemical used to kill a wide variety of insects. It is effective in controlling a variety of insects, including cutworms, corn rootworms, cockroaches, grubs, flea beetles, flies and termites. Used worldwide as an insecticide on grain, cotton, field, fruit, nut and vegetable crops, reports on its degradation are very few.
What was of concern was the way in which the pesticide residue was affecting non-target organisms, including other microbes whose functions were critical to crop production, soil sustainability and environmental quality.
These organophosphorous compounds have also been implicated in the nerve and muscular diseases in human beings
What the team of scientists at the Kerala University did was to collect a large number of soil samples, especially agricultural soil that had a history of repeated pesticide application. They managed to isolate five strains of bacteria from the soil in and around Vembayam. To their surprise they found that all the five strains tolerating the pesticide well under lab conditions.
“However one strain, Ochrobactrum thiophenivorans could completely degrade the chlorpyriphos under lab conditions. Once we complete our studies on this bacteria, it would have great significance in cleaning up the pesticide waste in the environment,” said Salom Gnana Thanga, who has been awarded a UGC grant to continue the work.
The nourishing growth medium in which this bacterium grows the best, has been standardised by the KU scientists. Once the bacteria starts multiplying in this medium, several generations of bacteria can be grown in a day and field application of the same can lead to reduced toxicity from pesticide residues.