Biomass from a full-scale anaerobic digester treating nitrogen-rich wastes was characterized by methanogenic batch activity assays at different ammonia concentrations. SAO was demonstrated by isotopic C fractionation of biogas components, at 3 – 6 gN-TAN. Microbial inhibition was found at 6 gN-TAN both in the acetate consumption rate and by genetic expression studies. Several homoacetogenic eub...

Although obligate syntrophic reactions cannot proceed without hydrogenotrophs, it has been unclear from the literature whether potential improvements are achievable with higher concentrations of hydrogenotrophs. In this study, the relative importance of formate-/H(2)-utilizing and acetate-utilizing trophic groups in the anaerobic degradation of butyrate and propionate was assessed by adding var...

The widespread use of methyl tert-butyl ether (MTBE) has caused major contamination of groundwater sources and is a concern due to its taste and odor problems, as well as its toxicity. MTBE can be degraded anaerobically which makes bioremediation of contaminated aquifers a potential solution. Nevertheless, the organisms and mechanisms that are responsible for anaerobic MTBE degradation are stil...

To understand the physiological basis of methanogenic archaea living on interspecies H(2) transfer, the protein expression of a hydrogenotrophic methanogen, Methanothermobacter thermautotrophicus strain ΔH, was investigated in both pure culture and syntrophic coculture with an anaerobic butyrate oxidizer Syntrophothermus lipocalidus strain TGB-C1 as an H(2) supplier. Comparative proteomic analy...

This study investigated the process of high-rate, high-temperature methanogenesis to enable very-high-volume loading during anaerobic digestion of waste-activated sludge. Reducing the hydraulic retention time (HRT) from 15 to 20 days in mesophilic digestion down to 3 days was achievable at a thermophilic temperature (55°C) with stable digester performance and methanogenic activity. A volatile s...

Agricultural activities have produced well-documented changes in the Florida Everglades, including establishment of a gradient in phosphorus concentrations in Water Conservation Area 2A (WCA-2A) of the northern Everglades. An effect of increased phosphorus concentrations is increased methanogenesis in the eutrophic regions compared to the oligotrophic regions of WCA-2A. The goal of this study w...