Bioextraction of Iron from Iron Oxides. Final Report, August 15, 1983-August 14, 1986

摘要

The feasibilities of (1) liberating free energy from dissimilative iron reduction and (2) coupling oxidative phosphorylation to electron transport to Fe(III) are sensitive to the aqueous chemistry of Fe(III). A systematic investigation of iron-reduction kinetics as a function of Fe(III) speciation indicated that in Pseudomonas sp. 200 (1) iron-reduction rate is functionally related to the concentrations of individual iron species and (2) direct contact between Fe(III) and the ferrireductase of Pseudomonas sp. 200 is required for electron transfer. When Fe(III) is provided as an iron oxide, overall reduction rate is much slower, though still dependent upon provision of an Fe(III)-complexing ligand. Again, direct contact between oxide surface and microorganism is requisite to iron reduction. In Pseudomonas sp. 200 there are both a constitutive and an inducible pathway for electron transport to Fe(III). The species is able to maximize development of useable chemical energy from respiration by regulating both the synthesis of ferrireductase and the direction of electron transfer when alternative (branched) pathways are present. 218 refs., 80 figs., 32 tabs. (ERA citation 12:007429)