Table 4.

Methanogenic archaea capable of metabolizing CO.

Species	Native physiology	Experimental procedure used	Inhibitory levelsA	Products from CO	Generation time on CO (h)	Reference
Mesophilic
Methanobrevibacter arboriphilicus	Hydrogenotrophic	Enzyme assay	N.D.	N.D.	N.D.	Hammel et al., 1984
Methanosarcina acetivorans C2A	Aceticlastic	Cultivation/enzyme assay	>150 kPa	Methane, acetate, formate	∼20	Rother and Metcalf, 2004; Oelgeschläger and Rother, 2009
Methanosarcina barkeri	Aceticlastic	Cultivation/enzyme assay	>100 kPa	Hydrogen, Methane	∼65	O’Brien et al., 1984; Bott et al., 1986
Methanobacterium formicicum	Hydrogenotrophic	Cultivation	N.D.	N.D.	No growth	Kluyver and Schnellen, 1947
Methanosaeta concillii	Aceticlastic	Enzyme assay	N.D.	N.D.	No growth	Jetten et al., 1989
Thermophilic
Methanothermobacter thermoautotrophicus	Hydrogenotrophic	Cultivation/enzyme assay	50 kPa	Methane, hydrogen	∼200	Daniels et al., 1977; Wasserfallen et al., 2000
Methanosarcina thermophila	Aceticlastic	Cultivation	>2 kPa	Hydrogen, Methane	N.D.	Zinder and Anguish, 1992
Methanothrix sp. Strain CALS-1	Aceticlastic	Cultivation	<2 kPa	Methane	No growth	Zinder and Anguish, 1992
Archaeoglobus fulgidusB	Sulfate reducer	Cultivation	>136 kPa	Acetate, formate	∼10	Henstra et al., 2007a

Not determined parameters are marked N.D.

^AForward arrows (>) indicate inhibitory levels have not been reached; numbers displayed are the maximal level tested. Reverse arrows (<) indicate the tested level was the highest tested and the inhibitory concentration lies below this level.

^BArchaeoglobus fulgidus is not capable of generating methane, but is displayed here due to its capacity to generate acetate and formate from CO, like M. acetivorans.