Variation of bacterial communities of anaerobic reactors treating an effluent contaminated with perchloroethylene

The effect of perchloroethylene (PCE) and the type of biomass (suspended and immobilized) on the diversity of microbial populations by 16S rDNA fragments amplified by PCR for bacteria (and further separated by DGGE) in two types of laboratory-scale methanogenic reactors (two complete mix reactors with suspended biomass, CM1 and CM2, and one fluidized-bed bioreactor with immobilized biomass, AFBBR) was studied. The bacterial and archaea communities in the CM were richer than those of AFBBR during three operations periods. Generally, microbial profiles in each reactor varied with time in a given period of operation. Despite the relative variation of microbial consortia with time, bioreactors showed steady state biochemical performance. PCE had a negative impact on the richness of CM consortia whereas this impact was less noticeable in the AFBBR. This is an abstract of a paper presented at the proceedings of the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).