Growth Properties of the Iron-reducing Bacteria, Shewanella putrefaciens IR-1 and MR-1 Coupling to Reduction of Fe(III) to Fe(II)

Shewanela, putrefaciene IR-1 and MR-1 were cultivated by using various combinations electron donor-acceptor, lactate-Fe(III) lactate-nitrate, pyruvate-FE(III), pyruvate-nitrate H$_2$ acetate-Fe(III) and H$_2$-acetate-nitrate. Both strains grew fermentatively on pyruvate and lactate but not on without and electron acceptor. In culture with Fe(III), both astrains grew on pyruvate and lactate but on H$_2$-acetate- CO$_2$. In cultivation with nitrate, both stains grew on pyruvate lactage and on H$_2$-acetate-CO$_2$ The growth yields of IR-1 pyruvate, pyruvate-Fe(III) and lactate-Fe(III) were about 3.4, 3.5, and 3.6(g cell/M substrate), respectively. From the growth properties of both strains on media with Fe(III) as an electron acceptor, the bacterial growth was confirmed not to be increased by addition of Fee(III) as an electron acceptor to the growth medium, which indicates a possibility that the dissimilatory reduction of Fe(III) to Fe(III) may not be coupled to free energy production.