Bacillus subtilis bacteria hinder the oxidation and hydrolysis of Fe2+ ions.
Bacteria are known to associate closely with secondary iron oxides in natural environments, but it is still unclear whether they catalyze their precipitation. Here, Fe2+ ions were progressively added to various concentrations of Bacillus subtilis bacteria in permanently oxic conditions while maintaining the pH at 6.5 by adding a NaOH solution at a monitored rate. The iron/ bacteria precipitates were characterized by wet chemistry, SEM, and XRD. Abiotic syntheses produced nanolepidocrocite, and their kinetics displayed a strong autocatalytic effect. Biotic syntheses led to the formation of tiny and poorly crystallized particles at intermediate bacterial concentrations and to a complete inhibition of particle formation at high bacterial concentrations. The occurrence of the autocatalytic effect was delayed and its intensity was reduced. Both the oxidation and the hydrolysis of Fe2+ ions were hindered.
Fakih
Mohamad
M
University of Rennes 1, CNRS, Géosciences Rennes, UMR 6118, Avenue du Général Leclerc, 35042 Rennes, France.
Châtellier
Xavier
X
Davranche
Mélanie
M
Dia
Aline
A
D001412:Bacillus subtilis / Q000378:metabolism*; D002384:Catalysis; D002621:Chemistry / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods; D006868:Hydrolysis; D007477:Ions; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D013997:Time Factors; D014961:X-Ray Diffraction
D007477:Ions; D012972:Sodium Hydroxide; D007501:Iron; D010100:Oxygen