IMMUNOLOGY OF METHANOGENIC BACTERIA

The purpose of this brief review is to highlight some of the findings made in the authors' laboratories using immunologic methods and antibody probes developed for analysis of methanogens directly in samples from bioreactors, avoiding culture isolation. A considerable diversity of methanogens was revealed by antigenic fingerprinting in bioreactors, larger than previously suspected. It was also found that the number and immunologic characteristics of the methanogenic subpopulations form a pattern distinctive of bioreactor type, feedstock and operating conditions. This pattern changed in response to perturbations and to temperature shifts. Time course quantitative measurements of methanogenic subpopulations demonstrated that these subpopulations undergo sequential changes during bioreactor operation. Parallel microbiologic, physiologic, and chemical determinations demonstrated the reliability of the immunologic methods and their potential for bioreactor monitoring and for manipulating microbes (e.g. to exclude a strain from a bioreactor). These immunologic methods were used to elucidate and monitor the methanogenic flora of a granular consortium over a period of several months. Each methanogenic subpopulation examined responded to a shift in temperature with changes in cell numbers and in its topography within the consortium.