title: Effect of chloride on ferrous iron oxidation by a Leptospirillum ferriphilum-dominated chemostat culture.
abstract: Biomining is the use of microorganisms to catalyze metal extraction from sulfide ores. However, the available water in some biomining environments has high chloride concentrations and therefore, chloride toxicity to ferrous oxidizing microorganisms has been investigated. Batch biooxidation of Fe(2+) by a Leptospirillum ferriphilum-dominated culture was completely inhibited by 12 g L(-1) chloride. In addition, the effects of chloride on oxidation kinetics in a Fe(2+) limited chemostat were studied. Results from the chemostat modeling suggest that the chloride toxicity was attributed to affects on the Fe(2+) oxidation system, pH homeostasis, and lowering of the proton motive force. Modeling showed a decrease in the maximum specific growth rate (micro(max)) and an increase in the substrate constant (K(s)) with increasing chloride concentrations, indicating an effect on the Fe(2+) oxidation system. The model proposes a lowered maintenance activity when the media was fed with 2-3 g L(-1) chloride with a concomitant drastic decrease in the true yield (Y(true)). This model helps to understand the influence of chloride on Fe(2+) biooxidation kinetics.
authors.affiliation: Department of Chemical Engineering and Geosciences, Luleå University of Technology, Sweden.
authors.forename: Chandra Sekhar
authors.initials: CS
authors.lastname: Gahan
authors.forename: Jan-Eric
authors.initials: JE
authors.lastname: Sundkvist
authors.forename: Mark
authors.initials: M
authors.lastname: Dopson
authors.forename: Ake
authors.initials: A
authors.lastname: Sandström
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism* / Q000633:toxicity*; D005296:Ferrous Compounds / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D002712:Chlorides; D005296:Ferrous Compounds