Biodegradation of Chloroaromatic Pollutants by a Bacterial Consortium from Paper and Pulp Mill Effluents

Chlorinated aromatic compounds are the major environmental pollutants because of their widespread use, toxicity and recalcitrance. The chloroaromatic pollutants from bleached Kraft pulp and paper mill effluents are released into the soil and water leading to their contamination. Bioremediation of industrial effluents using microorganisms may provide an effective and cost-effective method for detoxification. We have isolated a bacterial consortium capable of degrading chloroaromatic compounds from pulp and paper mill effluents by enrichment on 4-chlorobenzoic acid as sole source of carbon and energy. The four different bacterial isolates obtained from consortium were identified to be belonging to Pseudomonas species on the basis of their morphological and biochemical characteristics and by phylogenetic analysis based on their 16S rRNA gene sequences. The bacterial consortium utilized higher concentration (upto 5g/l) of 4-chlorobenzoic acid compared to individual isolates which utilized it upto 2g/l only. These indigenous bacterial isolates were found to be versatile in degrading a variety of chloroaromatic compounds including fluoro- and iodobenzoic acids, which are reported to be priority pollutants.