scholarly journals Alternative hydrogen uptake pathways suppress methane production in ruminants

2018 ◽  
Author(s):  
Chris Greening ◽  
Renae Geier ◽  
Cecilia Wang ◽  
Laura C. Woods ◽  
Sergio E. Morales ◽  
...  
Keyword(s):  
Methanogenic Archaea ◽  
Hydrogen Uptake ◽  
Primary Energy ◽  
Methane Yield ◽  
Comparative Genomic ◽  
Wolinella Succinogenes ◽  
Significant Differential Expression ◽  
Rumen Microorganisms ◽  
Carbohydrate Fermentation ◽  
Sheep Rumen

AbstractFarmed ruminants are the largest source of anthropogenic methane emissions globally. The methanogenic archaea responsible for these emissions use molecular hydrogen (H2), produced during bacterial and eukaryotic carbohydrate fermentation, as their primary energy source. In this work, we used comparative genomic, metatranscriptomic, and co-culture-based approaches to gain a system-wide understanding of the organisms and pathways responsible for ruminal H2metabolism. Two thirds of sequenced rumen bacterial and archaeal genomes encode enzymes that catalyze H2production or consumption, including 26 distinct hydrogenase subgroups. Metatranscriptomic analysis confirmed that these hydrogenases are differentially expressed in sheep rumen. Electron-bifurcating [FeFe]-hydrogenases from carbohydrate-fermenting Clostridia (e.g.Ruminococcus) accounted for half of all hydrogenase transcripts. Various H2uptake pathways were also expressed, including methanogenesis (Methanobrevibacter), fumarate reduction and nitrate ammonification (Selenomonas), and acetogenesis (Blautia). Whereas methanogenesis predominated in high methane yield sheep, alternative uptake pathways were significantly upregulated in low methane yield sheep. Complementing these findings, we observed significant differential expression and activity of the hydrogenases of the hydrogenogenic cellulose fermenterRuminococcus albusand the hydrogenotrophic fumarate reducerWolinella succinogenesin co-culture compared to pure culture. We conclude that H2metabolism is a more complex and widespread trait among rumen microorganisms than previously recognized. There is evidence that alternative hydrogenotrophs, including acetogens and selenomonads, can prosper in the rumen and effectively compete with methanogens for H2in low methane yield ruminants. Strategies to increase flux through alternative H2uptake pathways, including animal selection, dietary supplementation, and methanogenesis inhibitors, may lead to sustained methane mitigation.

scholarly journals Lovastatin-Enriched Rice Straw Enhances Biomass Quality and Suppresses Ruminal Methanogenesis

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Mohammad Faseleh Jahromi ◽  
Juan Boo Liang ◽  
Rosfarizan Mohamad ◽  
Yong Meng Goh ◽  
Parisa Shokryazdan ◽  
...  
Keyword(s):  
Rice Straw ◽  
Rumen Fluid ◽  
Methanogenic Archaea ◽  
Primary Objective ◽  
Gas Production ◽  
Cellulolytic Bacteria ◽  
Hmg Coa Reductase ◽  
Rumen Microorganisms ◽  
Coa Reductase

The primary objective of this study was to test the hypothesis that solid state fermentation (SSF) of agro-biomass (using rice straw as model); besides, breaking down its lignocellulose content to improve its nutritive values also produces lovastatin which could be used to suppress methanogenesis in the rumen ecosystem. Fermented rice straw (FRS) containing lovastatin after fermentation withAspergillus terreuswas used as substrate for growth study of rumen microorganisms usingin vitrogas production method. In the first experiment, the extract from the FRS (FRSE) which contained lovastatin was evaluated for its efficacy for reduction in methane (CH4) production, microbial population, and activity in the rumen fluid. FRSE reduced total gas and CH4productions (P<0.01). It also reduced (P<0.01) total methanogens population and increased the cellulolytic bacteria includingRuminococcus albus,Fibrobacter succinogenes(P<0.01), andRuminococcus flavefaciens(P<0.05). Similarly, FRS reduced total gas and CH4productions, methanogens population, but increasedin vitrodry mater digestibility compared to the non-fermented rice straw. Lovastatin in the FRSE and the FRS significantly increased the expression of HMG-CoA reductase gene that produces HMG-CoA reductase, a key enzyme for cell membrane production in methanogenic Archaea.

scholarly journals Contribution of Yeast Extract, Activated Carbon, and an Electrostatic Field to Interspecies Electron Transfer for the Bioelectrochemical Conversion of Coal to Methane

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4051 ◽  
Author(s):  
Dong-Mei Piao ◽  
Young-Chae Song ◽  
Gyung-Geun Oh ◽  
Dong-Hoon Kim ◽  
Byung-Uk Bae
Keyword(s):  
Activated Carbon ◽  
Yeast Extract ◽  
Electrostatic Field ◽  
Batch Reactor ◽  
Substrate Inhibition ◽  
Methanogenic Archaea ◽  
Methane Yield ◽  
Positive Role ◽  
Anaerobic Microorganisms ◽  
Coal Degradation

The bioelectrochemical conversion of coal to methane was investigated in an anaerobic batch reactor containing yeast extract and activated carbon. In anaerobic degradation of coal, yeast extract was a good stimulant for the growth of anaerobic microorganisms, and activated carbon played a positive role. An electrostatic field of 0.67 V/cm significantly improved methane production from coal by promoting direct and mediated interspecies electron transfers between exoelectrogenic bacteria and electrotrophic methanogenic archaea. However, the accumulation of coal degradation intermediates gradually repressed the conversion of coal to methane, and the methane yield of coal was only 31.2 mL/g lignite, indicating that the intermediates were not completely converted to methane. By supplementing yeast extract and seed sludge into the anaerobic reactor, the intermediate residue could be further converted to methane under an electrostatic field of 0.67 V/cm, and the total methane yield of coal increased to 98.0 mL/g lignite. The repression of the intermediates to the conversion of coal to methane was a kind of irreversible substrate inhibition. The irreversible substrate inhibition in the conversion of coal to methane could be attenuated under the electrostatic field of 0.67 V/cm by ensuring sufficient biomass through biostimulation or bioaugmentation.

scholarly journals Co-abundance analysis reveals hidden players associated with high methane yield phenotype in sheep rumen microbiome

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Leila Ghanbari Maman ◽  
Fahimeh Palizban ◽  
Fereshteh Fallah Atanaki ◽  
Naser Elmi Ghiasi ◽  
Shohreh Ariaeenejad ◽  
...  
Keyword(s):  
Methane Yield ◽  
Rumen Microbiome ◽  
Sheep Rumen

Health and nutrition in sheep receiving Bacillus thuringiensis

2019 ◽  
Vol 59 (6) ◽  
pp. 1119
Author(s):  
F. C. Campos ◽  
P. S. Corrêa ◽  
A. L. Abdalla Filho ◽  
J. Issakowicz ◽  
R. G. Monnerat ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Methanogenic Archaea ◽  
Experimental Period ◽  
Short Chain Fatty Acids ◽  
Nutrient Digestibility ◽  
Control Group ◽  
Apparent Digestibility ◽  
Animal Performance ◽  
Rumen Microorganisms ◽  
And Control

Performance, nutrient apparent digestibility, ruminal parameters, enteric methane (CH4) emission and blood parameters were studied in sheep receiving spores of Bacillus thuringiensis (Bt) in their diet. Twenty Santa Inês lambs (10 castrated males and 10 females) with 18.0 ± 3.50 kg initial bodyweight (BW) and 3 months of age were maintained in individual stalls in a completely randomised design. They were divided into two groups with five males and five females each (Bt 2036 group (n = 10) and control group (n = 10)). The animals of the Bt 2036 group received daily 2.5 × 106 spores of Bt 2036/kg BW and control animals received a placebo. The diet consisted of Tifton-85 (Cynodon spp.) hay ad libitum and 300 g/animal.day of concentrate mixture, which was adjusted according to growth requirements. During 53 days, animal performance was evaluated, with feed intake measured three times per week and lambs weighed fortnightly. Blood samples were taken every 15 days to evaluate hematological and biochemical parameters. Rumen fermentation was investigated in three stages (start, middle and end of the experimental period) using parameters such as pH, ammoniacal nitrogen, short chain fatty acids, and populations of Fibrobacter succinogenes, Ruminococcus flavefaciens, anaerobic fungi, methanogenic archaea and protozoa. At the end of the performance experiment, 18 lambs (Bt 2036 (n = 9), control (n = 9)) were selected for a digestibility trial, and placed in metabolic cages to estimate apparent nutrient digestibility, nitrogen balance and microbial protein synthesis. Ten male (Bt 2036 (n = 5), control (n = 5)) lambs were used to evaluate CH4 production using the hexafluoride tracer technique. There was no effect (P &gt; 0.05) of Bt 2036 on any of the evaluated parameters. The daily addition of 2.5 × 106 spores/kg BW of Bt 2036 in the ruminant diet did not cause any negative effects on hematological traits or animal poisoning, nor did it interfere with fermentation by rumen microorganisms, apparent digestibility of nutrients or animal performance.

Reliable method for assessing the COD mass balance of a submerged anaerobic membrane bioreactor (SAMBR) treating sulphate-rich municipal wastewater

2012 ◽  
Vol 66 (3) ◽  
pp. 494-502 ◽  
Author(s):  
J. B. Giménez ◽  
L. Carretero ◽  
M. N. Gatti ◽  
N. Martí ◽  
L. Borrás ◽  
...  
Keyword(s):  
Mass Balance ◽  
Membrane Bioreactor ◽  
Reliable Method ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Methanogenic Archaea ◽  
Anaerobic Treatment ◽  
Methane Yield ◽  
Yield Coefficient ◽  
Anaerobic Membrane Bioreactor

The anaerobic treatment of sulphate-rich wastewater causes sulphate reducing bacteria (SRB) and methanogenic archaea (MA) to compete for the available substrate. The outcome is lower methane yield coefficient and, therefore, a reduction in the energy recovery potential of the anaerobic treatment. Moreover, in order to assess the overall chemical oxygen demand (COD) balance, it is necessary to determine how much dissolved CH4 is lost in the effluent. The aim of this study is to develop a detailed and reliable method for assessing the COD mass balance and, thereby, to establish a more precise methane yield coefficient for anaerobic systems treating sulphate-rich wastewaters. A submerged anaerobic membrane bioreactor (SAMBR) treating sulphate-rich municipal wastewater was operated at 33 °C for an experimental period of 90 d, resulting in a high COD removal (approximately 84%) with a methane-enriched biogas of 54 ± 15% v/v. The novelty of the proposed methodology is to take into account the sulphide oxidation during COD determination, the COD removed only by MA and the dissolved CH4 lost with the effluent. The obtained biomethanation yield (333 L CH4 kg−1 CODREM MA) is close to the theoretical value, which confirms the reliability of the proposed method.

Influence of the concentration of peptides on [15N]ammonia incorporation and de novo synthesis of different amino acids by mixed microorganisms from the sheep rumen in vitro

1998 ◽  
Vol 1998 ◽  
pp. 175-175
Author(s):  
C. Atasoglu ◽  
N.D. Walker ◽  
C.J. Newbold ◽  
R.J. Wallace
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
De Novo ◽  
De Novo Synthesis ◽  
Rumen Microorganisms ◽  
Microbial Nitrogen ◽  
Sheep Rumen

Ammonia plays an important role in providing N for protein synthesis by rumen microorganisms. Studies using [15N]ammonia or [15N]urea indicate that the proportion of microbial nitrogen derived from ammonia is highly variable, ranging from 18 to 100% (Nolan, 1975; Salter et al., 1979). Peptides and amino acids are also incorporated by rumen microorganisms. They generally stimulate growth (Argyle & Baldwin, 1989), but little is known about the factors which govern the relative proportions of microbial amino acids which are derived from pre-formed amino acids and from ammonia. The present study was undertaken to determine how the concentration of peptides affects ammonia incorporation and the de novo synthesis of individual amino acids by mixed rumen microorganisms.

scholarly journals The surprising diversity of clostridial hydrogenases: a comparative genomic perspective

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1575-1588 ◽  
Author(s):  
Magdalena Calusinska ◽  
Thomas Happe ◽  
Bernard Joris ◽  
Annick Wilmotte
Keyword(s):  
Cell Metabolism ◽  
Methanogenic Archaea ◽  
Comparative Genomic ◽  
Hydrogen Metabolism ◽  
Fermentative Hydrogen Production ◽  
Fermentative Hydrogen ◽  
Clostridial Species ◽  
Micro Organisms ◽  
Reducing Bacteria ◽  
Modular Structures

Among the large variety of micro-organisms capable of fermentative hydrogen production, strict anaerobes such as members of the genus Clostridium are the most widely studied. They can produce hydrogen by a reversible reduction of protons accumulated during fermentation to dihydrogen, a reaction which is catalysed by hydrogenases. Sequenced genomes provide completely new insights into the diversity of clostridial hydrogenases. Building on previous reports, we found that [FeFe] hydrogenases are not a homogeneous group of enzymes, but exist in multiple forms with different modular structures and are especially abundant in members of the genus Clostridium. This unusual diversity seems to support the central role of hydrogenases in cell metabolism. In particular, the presence of multiple putative operons encoding multisubunit [FeFe] hydrogenases highlights the fact that hydrogen metabolism is very complex in this genus. In contrast with [FeFe] hydrogenases, their [NiFe] hydrogenase counterparts, widely represented in other bacteria and archaea, are found in only a few clostridial species. Surprisingly, a heteromultimeric Ech hydrogenase, known to be an energy-converting [NiFe] hydrogenase and previously described only in methanogenic archaea and some sulfur-reducing bacteria, was found to be encoded by the genomes of four cellulolytic strains: Clostridum cellulolyticum, Clostridum papyrosolvens, Clostridum thermocellum and Clostridum phytofermentans.

Influence of acetylation on peptide breakdown by microorganisms from the sheep rumen

1991 ◽  
Vol 1991 ◽  
pp. 46-46
Author(s):  
R.J. Wallace
Keyword(s):  
Amino Acids ◽  
Rumen Fluid ◽  
Peptide Chain ◽  
Ammonia Production ◽  
Host Animal ◽  
Rumen Microorganisms ◽  
Protein Nutrition ◽  
N Terminus ◽  
Sheep Rumen ◽  
Dipeptidyl Aminopeptidase

Protein is broken down by rumen microorganisms via peptides and amino acids to produce ammonia at rates which frequently exceed microbial requirements for N. Much of the ammonia-N formed in this way is eventually excreted as urea. If any of the steps in the degradation sequence could be inhibited, excessive ammonia production would be reduced. More protein, peptides or amino acids would escape fermentation in the rumen, thereby improving the protein nutrition of the host animal.The breakdown of peptides to amino acids is a central part of the degradation sequence. The main enzymic mechanism by which peptides are hydrolysed in the rumen is a bacterial dipeptidyl aminopeptidase, which cleaves dipeptides from the N-terminus of the peptide chain (Wallace & McKain, 1990). Little carboxypeptidase activity appears to be present. The present experiments were undertaken to find out to what extent blocking the N-terminus of peptides enables them to survive degradation in rumen fluid, and to determine which peptides can be protected in this way.

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