scholarly journals Energy-Conserving Enzyme Systems Active During Syntrophic Acetate Oxidation in the Thermophilic Bacterium Thermacetogenium phaeum

2019 ◽  
Vol 10 ◽  
Author(s):  
Anja Keller ◽  
Bernhard Schink ◽  
Nicolai Müller
Keyword(s):  
Thermophilic Bacterium ◽  
Acetate Oxidation ◽  
Enzyme Systems ◽  
Energy Conserving ◽  
Syntrophic Acetate Oxidation

Instability diagnosis and syntrophic acetate oxidation during thermophilic digestion of vegetable waste

2018 ◽  
Vol 139 ◽  
pp. 263-271 ◽  
Author(s):  
Dong Li ◽  
Yi Ran ◽  
Lin Chen ◽  
Qin Cao ◽  
Zhidong Li ◽  
...  
Keyword(s):  
Vegetable Waste ◽  
Acetate Oxidation ◽  
Syntrophic Acetate Oxidation ◽  
Thermophilic Digestion

scholarly journals Magnetite accelerates syntrophic acetate oxidation in methanogenic systems with high ammonia concentrations

2018 ◽  
Vol 11 (4) ◽  
pp. 710-720 ◽  
Author(s):  
Li Zhuang ◽  
Jinlian Ma ◽  
Zhen Yu ◽  
Yueqiang Wang ◽  
Jia Tang
Keyword(s):  
Acetate Oxidation ◽  
High Ammonia ◽  
Syntrophic Acetate Oxidation

scholarly journals Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

2013 ◽  
Vol 79 (20) ◽  
pp. 6491-6500 ◽  
Author(s):  
Dang P. Ho ◽  
Paul D. Jensen ◽  
Damien J. Batstone
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Retention Time ◽  
Elevated Temperatures ◽  
Stable Carbon Isotope ◽  
High Rate ◽  
Continuous Reactor ◽  
Waste Activated Sludge ◽  
Acetate Oxidation ◽  
Syntrophic Acetate Oxidation

ABSTRACTThis 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 solids (VS) destruction efficiency of 33 to 35% was achieved on waste-activated sludge, comparable to that obtained via mesophilic processes with low organic acid levels (<200 mg/liter chemical oxygen demand [COD]). Methane yield (VS basis) was 150 to 180 liters of CH4/kg of VSadded. According to 16S rRNA pyrotag sequencing and fluorescence in situ hybridization (FISH), the methanogenic community was dominated by members of theMethanosarcinaceae, which have a high level of metabolic capability, including acetoclastic and hydrogenotrophic methanogenesis. Loss of function at an HRT of 2 days was accompanied by a loss of the methanogens, according to pyrotag sequencing. The two acetate conversion pathways, namely, acetoclastic methanogenesis and syntrophic acetate oxidation, were quantified by stable carbon isotope ratio mass spectrometry. The results showed that the majority of methane was generated by nonacetoclastic pathways, both in the reactors and in off-line batch tests, confirming that syntrophic acetate oxidation is a key pathway at elevated temperatures. The proportion of methane due to acetate cleavage increased later in the batch, and it is likely that stable oxidation in the continuous reactor was maintained by application of the consistently low retention time.

scholarly journals Genome-Guided Analysis of the Syntrophic Acetate Oxidizer C. ultunense and Comparative Genomics Reveal Different Strategies for Acetate Oxidation and Energy Conservation in Syntrophic Acetate-Oxidising Bacteria

2018 ◽  
Author(s):  
Shahid Manzoor ◽  
Anna Schnürer ◽  
Erik Bongcam-Rudloff ◽  
Bettina Müller
Keyword(s):  
Energy Conservation ◽  
Proton Motive Force ◽  
Proton Pumps ◽  
Acetate Oxidation ◽  
Metabolic Diversity ◽  
Engineering Control ◽  
High Ammonia ◽  
Genes Encoding ◽  
Syntrophic Acetate Oxidation ◽  
Genome Scale

Syntrophic acetate oxidation operates close to the thermodynamic equilibrium and very little is known about the participating organisms and their metabolism. Clostridium ultunense is one of the most abundant syntrophic acetate-oxidising bacteria (SAOB) found in engineered biogas processes operating with high ammonia concentrations. It has been proven to oxidise acetate in cooperation with hydrogenotrophic methanogens. There is evidence that the Wood-Ljungdahl (WL) pathway plays an important role in acetate oxidation. In this study we analysed the physiological and metabolic capacities of C. ultunense on genome scale and conducted a comparative study of all known characterised SAOB, namely Syntrophaceticus schinkii, Thermacetogenium phaeum, Tepidanaerobacter acetatoxydans and Pseudothermotoga lettingae. The results clearly indicated physiological robustness beneficial for anaerobic digestion environments and revealed unexpected metabolic diversity with respect to acetate oxidation and energy conservation systems., Unlike S. schinkii and Th. phaeum, C. ultunense clearly does not employ the oxidative WL pathway for acetate oxidation, as its genome (and that of P. lettingae) lack important key genes. In both those species, a proton motive force is likely formed by chemical protons involving putative electron-bifurcating [Fe-Fe] hydrogenases rather than proton pumps. No genes encoding a respiratory Ech hydrogenase, as involved in energy conservation in Th. phaeum and S. schinkii, were identified in C. ultunense and P. lettingae. Moreover, two respiratory complexes sharing similarities to the proton-translocating ferredoxin:NAD+ oxidoreductase (Rnf) and the Na+ pumping NADH:quinone hydrogenase (NQR) were predicted. These might form a respiratory chain involved in reduction of electron acceptors other than protons. However, involvement of these complexes in acetate oxidation in C. ultunense and P. lettingae needs further study. This genome-based comparison provides a solid platform for future meta-proteomics and meta-transcriptomics studies and for metabolic engineering, control and monitoring of SAOB.

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