Anaerobic methanogenic consortia have a considerable resistance to oxygen exposure. Yet, most research has been focused on the study of the tolerance to oxygen of anaerobic immobilized biomass. Less is known on the potential of the anaerobic suspended biomass for withstanding exposure to oxygen and the effect of a primary degradable substrate on such resistance. Thus, the objective of this work...

a combination of an acidification reactor and an up-flow staged sludge bed (ussb) reactor wasapplied to treatment of molasses wastewater. the ussb, equipped with three gas solid separators, wasselected because of superior organic removal by means of good retention of granular sludge. the combinedsystem was continuously operated at mesophilic (35°c) conditions for 600 days. the ussb achieved a h...

Methanogenic archaea have been studied as model organisms for possible life on Mars for several reasons: they can grow lithoautotrophically by using hydrogen and carbon dioxide as energy and carbon sources, respectively; they are anaerobes; and they evolved at a time when conditions on early Earth are believed to have looked similar to those of early Mars. As Mars is currently dry and cold and ...

Culture-independent investigations of the bacterial diversity and activity in district heating systems with and without corrosion did not make it possible to relate one group of microorganisms with the observed corrosion. Fluorescence in situ hybridization by oligonucleotide probes revealed the dominance of beta-proteobacteria, sulphate reducing prokaryotes and alpha-proteobacteria. Analysis of...

Methanogenic archaea possess unusual seryl-tRNA synthetase (SerRS), evolutionarily distinct from the SerRSs found in other archaea, eucaryotes and bacteria. The two types of SerRSs show only minimal sequence similarity, primarily within class II conserved motifs 1, 2 and 3. Here, we report a 2.5 A resolution crystal structure of the atypical methanogenic Methanosarcina barkeri SerRS and its com...

Simulated municipal solid waste (MSW) based on the actual proportional characteristics of MSW was loaded into a simulated leachate recirculation bioreactor landfill and the abundance of common and tolerant microbes exposed to dibutyl phthalate (DBP) were investigated in the initial, acidic and methanogenic phases. The results showed that the abundance of bacteria was greatest, while that of act...

Methanogens and sulphate reducing bacteria compete for H2 in the human colon, and, as a result, faeces usually contain high concentrations of just one of these two organisms. There is controversy over which of these organisms wins the competition for H2, although theoretical data suggest that sulphate reducing bacteria should predominate. To elucidate this question experiments were undertaken i...

The bifunctional CO dehydrogenase/acetyl-CoA synthase (CODH/ACS) plays a central role in the Wood-Ljungdahl pathway of autotrophic CO(2) fixation. A recent structure of the Moorella thermoacetica enzyme revealed that the ACS active site contains a [4Fe-4S] cluster bridged to a binuclear Cu-Ni site. Here, biochemical and x-ray absorption spectroscopic (XAS) evidence is presented that the copper ...

Methane production by Methanothrix soehngenii VNBF grown on acetate (50 mM) as the sole carbon and energy source was influenced by the addition of Fe, trace elements, and pesticides. The addition of Fe and trace elements significantly enhanced the rate of CH(4) production. The addition of pesticides in the early growth phase caused complete inhibition. However, less inhibition was noted when pe...