Fe(III) reduction activity and cytochrome content of Shewanella putrefaciens grown on ten compounds as sole terminal electron acceptor

Abstract

Shewanella putrefaciens was grown on a series of ten alternate compounds as sole terminal electron acceptor. Each cell type was analyzed for Fe(III) reduction activity, absorbance maxima in reduced-minus-oxidized difference spectra and heme-containing protein content. High-rate Fe(III) reduction activity, pronounced difference maxima at 521 and 551 nm and a predominant 29.3 kDa heme-containing protein expressed by cells grown on Fe(III), Mn(IV), U(VI), SO 2− 3 and S 2O 2− 3, but not by cells grown on O 2, NO 3, NO 2 , TMAO or fumarate. These results suggest that microbial Fe(III) reduction activity is enhanced by anaerobic growth on metals and sulfur compounds, yet is limited under all other terminal electron-accepting conditions.