1. Methanogens and Ruminants

2. Overview Domain Archaea is divided into 3 subgroups:
Extreme halophiles
Extreme thermophiles
Methanogens
Methanogens are microorganisms that produce methane as a byproduct of its metabolism.
Methane molecules

3. What are methanogens? Use H2 to reduce CO2 to methane (CH4)
Usually coccoid or rod-shaped
Obligate anaerobes
Although they can’t function with O2, they can sustain oxygen stresses for prolonged times
Over 50 species have been identified
String of methanogen bacteria

4. Where are methanogens found?
Wetlands, where generated methane is called marsh gas
Guts of animals like ruminants (cattle, sheep, goats) and humans
Methanogens might be responsible for CH4 found in the atmosphere of Mars

5. What is a ruminant?
Animal with a stomach that has multiple compartments, which let it break down cellulose-rich foods (with the help of methanogens); it partially regurgitates its food (called cud) to help the digestive process
*Ruminants often have a thoughtful expression on their faces while they chew their cuds. This explains the origins of the name, which is derived from the Latin ruminare, the same root for the word “ruminate” as in “to think.”
(Methanogens found in the rumen)

6. Importance
Methanogens are important decomposers used in sewage treatment
Use methane gas as biofuel
Methane gas is a relatively potent greenhouse gas, thus contributing to global warming

7. Review Questions Name three places methanogens are found.
T/F- Methanogens can use O2 if it’s present.
Where are methanogens found in the ruminant’s digestive tracts?
Why can animals like cows break down cellulose and not humans?
Describe the shape of methanogens.
List two ways to use methanogens.

8. Answers to Review Questions
Wetlands, guts of ruminants, humans.
False.
In the rumen.
Ruminants have several compartments in their stomachs to thoroughly digest their food…whereas we don’t.
Coccoid or rod-shaped.
Break down wastes in sewage treatment and use the methane produced as biofuel.