Related Experiment Video
Updated: Nov 24, 2025
15:19
Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
10.0K
Formate-Dependent Heterodisulfide Reduction in a Methanomicrobiales Archaeon
Mohd Farid Abdul Halim1, Leslie A Day1, Kyle C Costa2
1Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, St. Paul, Minnesota, USA.
Applied and Environmental Microbiology
|December 28, 2020
Summary
Hydrogenotrophic methanogens use formate, not H2, as an electron donor for methanogenesis, challenging previous assumptions. This formate-dependent pathway is crucial for energy production in the Methanomicrobiales order.
Area of Science:
- Microbiology
- Biochemistry
- Environmental Science
Background:
- Hydrogenotrophic methanogens produce methane (CH4) using H2 to reduce CO2.
- Methanogens in the order Methanomicrobiales often lack typical hydrogenase genes, suggesting alternative electron donors.
- The metabolism of Methanomicrobiales is crucial in anaerobic environments but remains understudied.
Purpose of the Study:
- Investigate electron flow in Methanomicrobiales, focusing on heterodisulfide reductase (Hdr).
- Determine the role of Hdr and its associated enzymes in *Methanoculleus thermophilus*.
- Clarify the preferred electron donors for methanogenesis in this order.
Main Methods:
- Genetic and biochemical analysis of heterodisulfide reductase (Hdr) in *Methanoculleus thermophilus*.
- Enzyme purification and activity assays.
- Growth studies with different electron donors (H2, formate).
Main Results:
- Hdr from *M. thermophilus* copurified with formate dehydrogenase (Fdh) and required formate as an electron donor.
- No Hdr-associated hydrogenase was found; H2 could not serve as an electron donor.
- Cells exhibit formate hydrogenlyase activity, essential for generating formate for the Hdr reaction.
Conclusions:
- Formate is a critical electron donor for methanogenesis in *M. thermophilus*, integrated into the Hdr pathway.
- Hydrogen is not necessarily the preferred electron donor for all hydrogenotrophic methanogens.
- This study provides key insights into the unique metabolism of the order Methanomicrobiales.
Keywords:
Methanomicrobialesflavin-based electron bifurcationformate dehydrogenaseheterodisulfide reductasemethanogenesisMore Related Videos
04:32Extraction of Cofactor F420 for Analysis of Polyglutamate Tail Length from Methanogenic Pure Cultures and Environmental Samples
Published on: October 14, 2021
3.0K
07:31Author Spotlight: Designing Simple and Inexpensive Techniques to Grow Methane-Oxidizing Bacteria in the Laboratory
Published on: September 6, 2024
1.3K
Related Concept Videos
01:20Sulfur Assimilation
186
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to...
186
01:27Diversity of Archaea III
198
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like...
198
01:30Diversity of Archaea I
325
Archaea, a domain of single-celled microorganisms, are classified into five major phyla based on genetic and biochemical characteristics: Euryarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, and Nanoarchaeota. Among these, the phylum Euryarchaeota is notable for its remarkable diversity in morphology, metabolism, and ecological adaptations.Morphological and Metabolic DiversityMembers of Euryarchaeota exhibit a variety of cellular shapes, including rods and cocci. Their metabolic pathways...
325
01:29Archaeal Cell Wall
650
Archaeal cell walls are structurally and compositionally distinct from their bacterial counterparts, lacking the characteristic peptidoglycan layer found in most bacteria. Instead, archaeal cell walls exhibit remarkable diversity, utilizing materials such as pseudomurein, polysaccharides, and proteins to construct their protective outer layers. This structural flexibility is closely tied to archaea's ecological adaptability.S-Layers: The Common Archaeal Cell WallThe S-layer is the most...
650
01:15Metabolism of Chemolithotrophs
492
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation.
492
01:29Diversity of Archaea IV
260
Hyperthermophilic archaea are a group of extremophiles thriving at temperatures above 80°C, often in hydrothermal vents and volcanic soils where conditions surpass the boiling point of water. At such temperatures, proteins, membranes, and DNA in most organisms degrade, but hyperthermophiles have evolved remarkable adaptations to maintain stability and function.Unique Cellular FeaturesHyperthermophilic membranes are composed of a monolayer of biphytanyl tetraether lipids, which resist...
260