QUANTIFICATION OF METHANOGENIC GROUPS IN ANAEROBIC BIOLOGICAL REACTORS BY OLIGONUCLEOTIDE PROBE HYBRIDIZATION

The microbial community structure of anaerobic biological reactors was evaluated by using oligonucleotide probes complementary to conserved tracts of the 16S rRNAs of phylogenetically defined groups of methanog ens. Phylogenetically defined groups of methanogens were quantified an d visualized, respectively, by hybridization of P-32- and fluorescent- dye-labeled probes to the 16S rRNAs from samples taken from laboratory acetate-fed chemostats, laboratory municipal solid waste digestors, a nd full-scale sewage sludge digestors. Methanosarcina species, members of the order Methanobacteriales, and Methanosaeta species were the mo st abundant methanogens present in the chemostats, the solid-waste dig estors, and the sewage sludge digestors, respectively.