A study of three anaerobic methanogenic bioreactors reveals that syntrophs are diverse and different from reference organisms

Abstract

Calibrated antibody probes for homoacetogenic, syntrophic acetogenic, and sulfate‐reducing Bacteria were generated and used, along with probes for methanogenic Archaea, to elucidate the bacterial biofilm population of three fluidized bed bioreactors fed with different substrates. The new probes were for Clostridium formicoaceticum, Syntrophomonas wolfei subsp. wolfei, Syntrophospora bryantii, Syntrophococcus sucromutans strain S195, and Desulfobulbus propionicus strain 1pr3. Microscopic and electron microscopic analyses showed a complex microbial flora in the three bioreactors. This was confirmed by the antigenic fingerprinting method which showed a diversity of methanogens and syntrophs. The subpopulations that could be identified were only moderately or weakly related to reference immunotypes, and were quantitatively small. Thus, these and the major populations from the quantitative and functional standpoints, belong to as yet uncharacterized immunotypes, and possibly include new strains and species.

Quantitative detection of culturable methanogenic archaea abundance in anaerobic treatment systems using the sequence-specific rRNA cleavage method

“…In reactor 1, approximately half of the detectable methanogens was affiliated with the genus Methanobrevibacter commonly observed in mesophilic methanogenic bioprocesses treating several types of wastewater (Grotenhuis et al, 1991;Wu et al, 1991;Harmsen et al, 1996;Zellner et al, 1997). It was reported that the relative abundances of Methanobrevibacter-related methanogens represented o1.5% of total microbial populations during the start-up operation of a UASB process (Zheng et al, 2006).…”

Methane yield and microscopic observation as monitoring biofilm behaviour parameters, during start up phase of anaerobic inverse fluidized bed reactor

“…separation of treated water from biomass, increased solid retention time, greater surface contact between organic matter and biomass, and a compact system design (Garcia-Calderon et al, 1998;Sowmeyan and Swaminathan, 2008a). A serious disadvantage is the long required start-up period due to low biofilm growth rate (Zellner et al, 1997;Alvarado-Lassman et al, 2010). Traditional biofilm growth characterization methods involve periodic observation and biomass sampling for external analysis to determine solids, proteins, polysaccharides, and phospholipids contents.…”

Detection of Active Butyrate-Degrading Microorganisms in Methanogenic Sludges by RNA-Based Stable Isotope Probing

“…We have detected only three clones (two clones from sludge TP and one clone from sludge MBF) related to Syntrophomonadaceae species that were typically shown to be fatty acid-degrading microorganisms under the methanogenic conditions in this study (Table 1). Previously, Zellner et al reported that organisms related to Syntrophomonadaceae species were not abundant enough to contribute to the observed butyrate turnover rate in the bioreactors (25). They concluded that the main syntrophic butyrate-oxidizing bacteria in the reactors might be an as-yet-unknown species.…”

“…Due to the fastidious nature of this syntrophic metabolism, isolation of butyrate-degrading syntrophs has been difficult and thus information on butyratedegrading bacteria is based on some isolates belonging to the family Syntrophomonadaceae. Due to this lack of knowledge and the lack of appropriate molecular markers, culture-independent studies have focused only on species of the family Syntrophomonadaceae (5,15,25). Consequently, the natural diversity of syntrophic butyrate-degrading bacteria has not been studied in any detail.…”