Characterization of microbial communities in anaerobic bioreactors using molecular probes

Abstract

The microbial community structure of twenty-one single-phase and one two-phase full-scale anaerobic sewage sludge digesters was evaluated using oligonucleotide probes complementary to conserved tracts of the 16S rRNAs of phylogenetically defined groups of methanogens and sulfate-reducing bacteria. These probe results were interpreted in combination with results from traditional chemical analyses and metabolic activity assays. It was determined that methanogens in "healthy" mesophilic, single-phase sewage sludge digesters accounted for approximately 8-12% of the total community and that Methanosarcinales and Methanomicrobiales constituted the majority of the total methanogen population. Methanobacteriales and Methanococcales played a relatively minor role in the digesters. Phylogenetic groups of mesophilic, Gram-negative sulfate-reducing bacteria were consistently present at significant levels: Desulfovibrio and Desulfobulbus spp. were the dominant sulfate-reducing populations, Desulfobacter and Desulfobacterium spp. were present at lower levels, and Desulfosarcina, Desulfococcus, and Desulfobotulus spp. were absent. Sulfate reduction by one or more of these populations played a significant role in all digesters evaluated in this study. In addition, sulfate-reducing bacteria played a role in favoring methanogenesis by providing their substrates. The analysis of the two-phase digester indicated that true phase separation was not accomplished: significant levels of active methanogens were present in the first phase. It was determined that the dominant populations in the second phase were different from those in the single-phase digesters.

Effect of Sulfide Inhibition and Organic Shock Loading on Anaerobic Biofilm Reactors Treating a Low‐Temperature, High‐Sulfate Wastewater

“…In natural environments, M. concilii were the dominant MA in Antarctic sediments (Purdy et al 2003b), chlorinated-solvent contaminated aquifers (Dojka et al 1998), and gas-condensate contaminated aquifers with high levels of sulfate (Struchtemeyer et al 2005). M. concilii were also found to predominate in engineered systems treating sewage or municipal solid waste (Griffin et al 1998;McMahon et al 2001;Raskin et al 1995b;Zheng and Raskin 2000), and industrial effluents (Plumb et al 2001). In one study, M. concilii were found to make up 90% of the archaeal community in an anaerobic digester (Merkel et al 1999).…”

“…It was also found that Methanosaeta were the dominant aMA, Methanobacterium were the dominant hMA, and Desulfobulbus was important for propionate degradation. Raskin et al (1995b) analyzed samples from 21 anaerobic sludge digesters. They determined that Methanosaeta were the dominant MA in most samples and Desulfovibrio and Desulfobulbus, both iSRB, were the dominant SRB groups.…”

Biomass retention on electrodes rather than electrical current enhances stability in anaerobic digestion

“…Triplicate samples of a 100-fold dilution of the DNA-samples were analyzed for total bacteria, total archaea and the methanogenic methanogenic populations Methanobacteriales, Methanomicrobiales, Methanosarcinaceae and Methanosaetaceae. Total archaea can be considered a valid estimation of total methanogens in AD, because of the highly unfavourable conditions of nonmethanogenic archaea in AD (Raskin et al 1995, Woese et al 1990). To quantify total bacteria the general bacterial primers P338F (5'-ACTCCTACGGGAGGCAGCAG-3') and P518r (5'-ATTACCGCGGCTGCTGG-3'), as described by Ovreas et al (1997), were used.…”

Desulfobacter vibrioformis sp. nov., a Sulfate Reducer from a Water-Oil Separation System

“…Only a few Desulfobacter species, D. postgatei, D. hydrogenophilus, D. latus, and D. cuwatus, have been validly described (40). Although other members of the Desulfobacter genus have been recently detected, e.g., by oligonucleotide probes, in various locations like bioreactors (33), oil field environments (7, 39), and photosynthetic biofilms (32), none of them has been isolated and characterized.…”