A STUDY OF 3 ANAEROBIC METHANOGENIC BIOREACTORS REVEALS THAT SYNTROPHS ARE DIVERSE AND DIFFERENT FROM REFERENCE ORGANISMS

Calibrated antibody probes for homoacetogenic, syntrophic acetogenic, and sulfate-reducing Bacteria were generated and used, along with prob es for methanogenic Archaea, to elucidate the bacterial biofilm popula tion of three fluidized bed bioreactors fed with different substrates. The new probes were for Clostridium formicoaceticum, Syntrophomonas w olfei subsp. wolfei, Syntrophospora bryantii, Syntrophococcus sucromut ans strain S195, and Desulfobulbus propionicus strain 1pr3. Microscopi c and electron microscopic analyses showed a complex microbial flora i n the three bioreactors. This was confirmed by the antigenic fingerpri nting method which showed a diversity of methanogens and syntrophs. Th e subpopulations that could be identified were only moderately or weak ly related to reference immunotypes, and were quantitatively small. Th us, these and the major populations from the quantitative and function al standpoints, belong to as yet uncharacterized immunotypes, and poss ibly include new strains and species.