Research Highlight

Friends from bugland

Subhra Priyadarshini

doi:10.1038/nindia.2007.1 Published online 1 May 2007

Common Effluent Treatment Plants (CETPs), which collect garbage from industry clusters, house a large number of 'good bacteria' capable of cleaning up water, environment scientists have found. The finding, they contend, could completely change the way industries treat their wastewater1.

A clutch of ‘good bacteria’


CETPs, the biological wastewater treatment facilities, receive inputs from a variety of industry. About 25 to 30 different kinds of bacteria work as a community and biodegrade the thousands of harmful chemicals in this wastewater.

While studying two CETPs in Mumbai and Hyderabad, the researchers identified over 200 kinds of bacteria by sequencing their DNA through a technique called 16 rDNA cloning. These bacteria, some of them unidentified, showed tough action against certain kinds of chemicals in the wastewater.

Lead researcher Hemant Purohit says more than half of the bacteria cloned from the wastewaters were unidentified and not culturable by known techniques. These represent the vast unexplored bacterial diversity of CETPs. "Unfortunately, the biomass is treated as a 'black box' in wastewater treatment. Our study is an initial analysis of bacteria in them responsible for conversion of toxic pollutants into harmless compounds," he says.

The team recorded data from three seasons. Of the 37 genera of bacteria identified, six could be detected using both culture-based and culture independent tools while the remaining 31 were detected by either of the two methods. "This shows how important it is to use both tools to analyse such ecosystems," Purohit says.

While environment genomic experts have extensively explored soil microbes, very few studies have mapped microbial populations responsible for converting harmful compounds into harmless ones. In all, the scientists detected a total of 76 culturable and over 200 unidentified strains. They will now study the strains to identify antibiotics that could kill certain bacteria in the microbial ecosystems.

The authors of this work are from: Environmental Genomics Unit, National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440 020, India; Department of Microbiology, Ghent University Hospital, De Pintelaan 185, B9000 Gent, Belgium


  1. Purohit, H. J. et al. Eubacterial diversity of activated biomass from a common effluent treatment plant. Res. Microbiol. 158, 494-500 (2007). | Article | PubMed |