Integrated biological approach for the enhanced degradation of lindane

400-406Lindane is a persistent organic pollutant (POP) and its removal from various environmental compartments is a global priority. In the present study, three lindane degrading bacterial cultures, viz. Pseudoarthrobacter sp., Pseudomonas sp. and Klebsiella sp., were selected from among ten isolates obtained from lindane-exposed soils by enrichment culture technique. The cultures exhibited a maximum lindane degradation efficiency of ~50%, having little significance in bioremediation. However, in the presence of protozoa (ciliates) obtained from the same enrichment culture, lindane degradation efficiency of bacterial cultures increased to the tune of 90-92% with concomitant formation of 1,2,4-trichlorobenzene, a key degradation product. Lindane degradation by the bacterial cultures was also found to get enhanced by 10-15% in the presence of root exudates of lindane-tolerant plants, viz. corn, chili and coriander, even though these plants were unable to uptake any lindane and thus were unsuitable for phytoremediation per se. These data highlight the need for an intensive investigation on (a) bacteria-protozoa interactions for bioremediation of POPs and (b) use of POP-degrading bioinoculants in the rhizospheric soil of resistant plants as a possible alternative, in the absence of a viable conventional remedial option