Degradation of Amino Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474 Influence of Methanogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475 Obligately Syntrophic Amino Acid Deamination . . . . . . . 475 Syntrophic Arginine, Threonine, and Lysine Fermentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475 Facu...

Considerable variability in methane production and emissions has been reported mangroves, explained by inhibition oxidation. In this study, soil pore waters were collected from mangrove forests located the Gulf of California (Mexico) exposed to shrimp farm disturbance. The δ13C dissolved inorganic carbon (DIC) CH4 analyzed along with organic matter assess proportion CO2 derived methanogenesis, ...

Hydrogen is a central metabolite in rumen fermentation and its partial pressure is an important determinant of rumen methanogenesis. The balance of hydrogen ion (H+) and dissolved hydrogen gas (H2) concentrations directly determine the redox potential of the rumen and therefore the possible extent of oxidation of feedstuffs. Differential permeability of the bacterial membrane to H+ and H2 means...

The feasibility of co-digestion of chicken manure (CM) and maize silage (MS) without water dilution was investigated in 5-L digesters. Specific methane production (SMP) of 0.309LCH4g(-1) volatile solids (VS) was achieved but only at lower %CM. Above a critical threshold for total ammonia nitrogen (TAN), estimated at 7gNL(-1), VFA accumulated with a characteristic increase in acetic acid followe...

This paper builds a quantitative thermodynamic model for the microbial hydrolysis process (MHP, which uses Caldicellulosiruptor bescii at 75°C pre-digestion) producing biogas from 5-10% aqueous suspension of dairy manure (naturally buffered near pH 7.8 by ammonium bicarbonate) anaerobic digestion with mix acetoclastic and syntrophic methanogenesis. Standard Gibbs energy changes were calculated ...

The ongoing global temperature rise enhances permafrost thaw in the Arctic, allowing Pleistocene-aged frozen soil organic matter to become available for microbial degradation and production of greenhouse gases, particularly methane. Here, we examined extent mechanism anaerobic oxidation methane (AOM) sediments four interior Alaska thermokarst lakes, which formed continue expand as a result ice-...

The kinetics of propionate degradation, acetate splitting, and hydrogen consumption in digesting sludge were investigated in a lab-scale digester. At natural steady-state conditions, the acetate-splitting systems in well-digested sludge were about half saturated. Propionate-degrading systems were saturated to only 10 to 15%, and hydrogen removal was less than 1% of the maximum possible rate. It...

Biological methanogenesis is linked to permanent water logged systems, e.g., rice field soils or lake sediments. In these systems the methanogenic community as well as the pathway of methane formation are well-described. By contrast, the methanogenic potential of river sediments is so far not well-investigated. Therefore, we analyzed (a) the methanogenic potential (incubation experiments), (b) ...