Table 1. Growth characteristics of the newly isolated Hydrogenophaga sp. strain AR20.

Electron acceptors	Electron donors
	Yeast extract	Glucose	Acetate	Succinate	Formate	Hydrogen
Electrode	+++	−	−	+	+	++
Oxygen	+++	−	−	+	+	++
Nitrate	+++	−	−	+	+	++
Nitrite	++	−	−	−	−	+
Sulfate	−	−	−	−	−	−
Fe(III)	+	−	−	−	−	+

Abbreviation: OD, optical density.

Growth was determined as OD₆₀₀ after 96-h incubation.

−, OD₆₀₀ <0.01; +, OD₆₀₀ >0.01; ++, OD₆₀₀ >0.10; +++, OD₆₀₀ >0.30.