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Oxygen sensitivity of methanogenic bacteria
1Mikrobiologisches Institut ETH Zürich, ETH-Zentrum, 8092 Zürich, Switzerland.
Systematic and Applied Microbiology
|December 1, 2012
Summary
Five species of methanogenic bacteria were tested for oxygen sensitivity. Some strains showed resistance to oxygen for up to 30 hours, while others experienced rapid cell death upon air exposure.
Area of Science:
- Microbiology
- Extremophile Research
- Anaerobic Microbiology
Background:
- Methanogenic archaea are crucial anaerobic microorganisms.
- Understanding their oxygen sensitivity is vital for cultivation and ecological studies.
- Previous data on oxygen tolerance in methanogens is limited.
Purpose of the Study:
- To quantitatively assess the oxygen sensitivity of five diverse methanogenic bacterial strains.
- To establish standardized conditions for reproducible oxygen exposure experiments.
- To differentiate oxygen tolerance patterns among different genera of methanogens.
Main Methods:
- Culturing five methanogenic bacterial strains to exponential growth.
- Plating cells on solid media with >80% plating efficiency.
- Exposing starved cell suspensions in non-reduced buffer to air under controlled conditions.
- Analyzing survival curves (colony-forming units) over time.
Main Results:
- Methanobacterium thermoautotrophicum, Methanobrevibacter arboriphilus, and Methanosarcina barkeri exhibited biphasic death curves, with rapid viability loss after 30 hours of oxygen exposure.
- Methanococcus voltae and Methanococcus vannielii showed exponential survival reduction without a lag phase, reaching 99% kill within 10 hours.
- Significant differences in oxygen sensitivity were observed across the tested methanogenic genera.
Conclusions:
- Methanogenic bacteria display varied responses to oxygen exposure.
- Methanococcus species are highly sensitive to oxygen, while others show a degree of tolerance.
- These findings aid in optimizing cultivation techniques and understanding the ecological niches of methanogens.
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