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Medium Preparation for the Cultivation of Microorganisms under Strictly Anaerobic/Anoxic Conditions
Published on: August 15, 2019
Hydrogenotrophic methanogens dominate in biogas reactors fed with defined substrates
K Kampmann1, S Ratering, R Baumann
1Justus-Liebig-University Gießen, Institute of Applied Microbiology, IFZ, Gießen, Germany. kristina.kampmann@umwelt.uni-giessen.de
Systematic and Applied Microbiology
|August 25, 2012
Summary
Biogas reactor microbial communities were analyzed using PCR and SSCP. High methanogen abundance was observed, with ammonia levels potentially inhibiting acetoclastic methanogens.
Area of Science:
- Microbiology
- Environmental Science
- Biotechnology
Background:
- Biogas production relies on methanogenic archaea.
- Understanding microbial community dynamics is crucial for optimizing biogas reactors.
Purpose of the Study:
- To investigate the methanogenic communities in a laboratory-scale biogas reactor fed with different substrates.
- To characterize the dominant methanogens and assess the impact of ammonia concentration on community structure.
Main Methods:
- Real-time PCR targeting the methyl coenzyme-M reductase (mcrA) gene for quantifying methanogens.
- Single-strand conformation polymorphism (SSCP) analysis and DNA sequencing for community profiling.
- Most probable number (MPN) cultivations to determine cell counts with different substrates.
Main Results:
- Methanogen copy numbers reached up to 2.1×10^9 g dry mass(-1).
- A stable community dominated by hydrogenotrophic methanogens was observed, with one species closely related to Methanospirillum hungatei and another distantly related to Methanopyrus kandleri.
- Acetoclastic methanogens related to Methanosarcina mazei were detected in acetate and methanol cultivations but not in the main reactor samples.
- High ammonia concentrations (2.48–3.61 g NH4-NL(-1)) in the reactor were hypothesized to inhibit acetoclastic methanogens.
Conclusions:
- The study identified key hydrogenotrophic methanogens in the biogas reactor.
- High ammonia levels likely suppressed the activity and growth of acetoclastic methanogens, impacting overall biogas production efficiency.
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