Related Experiment Video
Updated: Oct 11, 2025
07:31
Author Spotlight: Designing Simple and Inexpensive Techniques to Grow Methane-Oxidizing Bacteria in the Laboratory
Published on: September 6, 2024
1.1K
Syntrophic propionate-oxidizing bacteria in methanogenic systems.
Maria Westerholm1, Magdalena Calusinska2, Jan Dolfing3
1Department of Molecular Sciences, Swedish University of Agricultural Sciences, BioCentre, Almas allé 5, SE-75007 Uppsala, Sweden.
FEMS Microbiology Reviews
|December 7, 2021
Summary
Syntrophic propionate-oxidizing bacteria (SPOB) are crucial for energy production in anaerobic systems. This review explores SPOB metabolism, ecology, and their role in biogas production and climate change.
Area of Science:
- Microbiology
- Environmental Science
- Biotechnology
Background:
- Syntrophic propionate degradation is energy-limited, often bottlenecking methanogenic systems.
- Understanding syntrophic propionate-oxidizing bacteria (SPOB) is vital for engineered and natural ecosystems.
- SPOB play a role in biogas production, biomass-derived chemicals, and biogenic methane emissions.
Purpose of the Study:
- To review the ecology, physiology, and metabolic capacities of SPOB.
- To discuss distinctions in gene repertoire and organization related to propionate metabolism.
- To identify environmental conditions governing propionate oxidation.
Main Methods:
- Literature review of cultivations, thermodynamic calculations, and omic analyses.
- Analysis of gene repertoire for the methylmalonyl-CoA pathway, hydrogenases, and formate dehydrogenases.
- Examination of electron transfer mechanisms (formate/hydrogen/direct).
Main Results:
- SPOB exhibit diverse metabolic capabilities beyond syntrophy.
- Variations in SPOB interplay with partners highlight nuances in their syntrophic lifestyle.
- Environmental conditions significantly influence propionate oxidation rates.
Conclusions:
- This review enhances understanding of SPOB basic and applied science.
- Knowledge gaps in SPOB metabolism and ecology are identified.
- Future research and engineering efforts on propionate metabolism are encouraged.
Related Concept Videos
01:15Metabolism of Chemolithotrophs
302
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.
302
01:28Anoxygenic Phototrophic Bacteria
255
Anoxygenic phototrophic bacteria are a diverse group of microorganisms that perform photosynthesis without producing oxygen. They primarily include purple sulfur bacteria, purple nonsulfur bacteria, green sulfur bacteria, and green nonsulfur bacteria. These bacteria are classified into the Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi, and Chloroflexi lineages, each with distinct physiological and ecological adaptations.Purple sulfur bacteria belong to the...
255
01:30Anoxygenic Photosynthesis
277
Anoxygenic photosynthesis is a phototrophic process that captures light energy to drive carbon fixation without producing molecular oxygen. Unlike oxygenic photosynthesis, which utilizes water as an electron donor and releases oxygen, anoxygenic phototrophs use alternative electron donors such as hydrogen sulfide (H₂S), elemental sulfur (S⁰), or thiosulfate (S₂O₃²⁻). This process is carried out by diverse groups of bacteria, including purple bacteria, green...
277
01:28Microbial Nutrition
498
Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...
498
01:28Carbon-dioxide Fixation
156
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
156
01:21Hyperthermophilic Bacteria
140
Domain Bacteria includes some unique hyperthermophilic species. They exhibit remarkable adaptations that enable survival in extreme environments.Thermotoga species are rod-shaped, gram-negative, non-sporulating hyperthermophiles that form a sheath-like envelope called a toga. They ferment sugars or starch, producing lactate, acetate, CO₂, and H₂, and can also grow via anaerobic respiration using H₂ and ferric iron. Found in hot springs and hydrothermal vents, over 20% of their...
140