TABLE 1.

Results of growth substrate tests

Growth substrate (electron donor)	Concn or amt	Electron acceptora	Growth
Solid substrates
FeS	Plug	O2	+
FeCO3	Plug	O2	+
		NO3− (5 mM)	+
FeS2	1 g of particles	O2	+
Basalt	∼10 wt% FeO	O2	+
Aqueous substrates
FeCl2 · 4H2O	10 mM	O2	+
		NO3− (5 mM)	+
MnCl2 · 4H2O	10 mM	O2	−
HS−	100 μM	O2	−
Na2S2O3	10 mM	O2	−
Yeast extract	0.1 g/ml	O2	−
Peptone	0.1 g/ml	O2	−
Sucrose	10 mM	O2	−
Dextrose	10 mM	O2	−
Acetate	10 mM	O2	−
Lactate	10 mM	O2	−
Medium only	See text	O2	−
		SO42− (30 mM)	−

^aThe O₂ concentrations were not determined.