TABLE 2.

CoM levels in various methanogens and CoM levels per cell

Organism	Amt of CoM		Direct count procedure		MPN estimation procedure
	nmol/mg of protein	nmol/ml	No. of cells/ml	fmol of CoM/cell	No. of cells/ml	fmol of CoM/cell
Methanolobus tindarius	11.49	0.56
Methanospirillum hungatei	19.41	0.52	7.40 × 105	0.70	1.1 × 106	0.47
Methanosarcina barkeri (grown on N2-CO2-methanol)	41.11	1.97	4.60 × 106	0.43
Methanosarcina barkeri (grown on N2-CO2-acetate)	6.13	0.70	1.80 × 106	0.39
Methanosarcina barkeri (grown on H2-CO2)	18.21	1.78
Methanosaeta concilli	6.59	0.38
Methanococcus voltae	23.75	1.45	6.20 × 106	0.23
Methanococcus thermolithotrophicus	41.09	2.59	5.15 × 106	0.50	7.5 × 106	0.34
Methanobacterium thermoautotrophicum Marburg	7.48	0.40	2.85 × 106	0.14	1.1 × 107	0.36