IIT-Bombay researchers find bacteria that may help remove pollutants

MUMBAI: While carrying out a routine experiment on degradation of pollutants, researchers from IIT-Bombay have stumbled upon an organism which preferentially feeds on hazardous aromatic pollutants over glucose. The discovery of this strain of bacterium, called Pseudomonas putida CSV86, can help in eliminating a diverse range of aromatic pollutants such as naphthalene (in household insect repellents), benzoate (in food preservatives), plastics and industrial chemicals.




The findings of the study, which was published in the journal Applied and Environmental Microbiology, will not only help in getting rid of pollutants in waste water by breaking them down into safer chemicals, but further gene study could have implications in the field of agriculture too.

Most living organisms are known for consuming glucose over other complex compounds in the process of degradation, explained professor Prashant Phale, from the department of biosciences and bioengineering at IIT-Bombay, who led the study. “This preferential behaviour of living organism choosing the simple source of carbon first - in this case glucose - is well known as carbon catabolite repression in biochemistry. However, this particular strain of bacteria showed the exact opposite behaviour when we studied it in isolation. Given glucose and aromatic compounds together, the organism preferentially metabolises aromatic compounds first. It moves on to glucose only when the aromatic compounds are exhausted,” said Phale. The bacterium’s peculiar order of preference can help in removal of harmful pollutants even in the presence of simpler carbon sources.

“It is the first time that such an organism has been discovered,” said Phale. In most bacteria, the presence of simple carbon sources like glucose supresses the expression of genes (process by which information from a gene is used in synthesis of a functional gene product) that help in breaking down aromatic compounds. This phenomenon is reversed in the CSV86 strain, with aromatic compounds suppressing the use of glucose. The researchers are trying to do experiments at molecular level on why the organism behaves differently. “We are trying to identify the factors/proteins involved in rendering preferential utilisation of aromatics over glucose,” said Phale.

“My lab is continuing its work on this strain, which was isolated from Indian soil. The strain, displaying the unique property, is only with us at IIT-Bombay and has not been reported by any research group or in any scientific literature,” said Phale. He added that their findings could help in producing genetically engineered CSV86 strain to efficiently break down any desired aromatic compound. “It could also find an important application in the field of agriculture. The strain introduced into the soil could be used to preferentially degrade aromatic components of pesticides and insecticides to naturally cleanse the environment without harming the plants. This bacterium belongs to genus Pseudomonas, which promotes plant growth,” added Phale.