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Reductive dissolution of fe(III) oxides by Pseudomonas sp. 200
Author(s) -
Arnold Robert G.,
DiChristina Thomas J.,
Hoffmann Michael R.
Publication year - 1988
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260320902
Subject(s) - dissolution , nitrilotriacetic acid , chemistry , hematite , kinetics , goethite , ligand (biochemistry) , inorganic chemistry , iron oxide , magnetite , oxide , metal , redox , nuclear chemistry , chelation , mineralogy , adsorption , metallurgy , materials science , organic chemistry , biochemistry , physics , receptor , quantum mechanics
The kinetics and mechanism of reductive dissolution of Fe(III) oxides were examined in pure, batch cultures of Pseudomonas sp. 200. Primary factors controlling hematite dissolution kinetics were mineral surface area (or concentration of high‐energy surface sites), ligand concentration, and cell number. In the presence of nitrilotriacetic acid (NTA), saturation kinetics were apparent in the relationship governing reductive dissolution of hematite. A kinetic expression was developed in which overall iron‐reduction rate is functionally related to the concentrations of both NTA and Fe(III). Addition of NTA resulted in a 20‐fold increase in the microbial rate of mineral (reductive) dissolution. Mechanisms in which NTA served as a bridging ligand, shuttling respiratory electrons from the membrane‐bound microbial electron transport chain to the metal center of the iron oxide, or accelerated the departure of Fe(II) centers (bound to ligand) from the oxide surface following reduction have been postulated. Experimental results indicated that cell–mineral contact was essential for reductive dissolution of goethite.