Formation of Fe-sulfides in cultures of sulfate-reducing bacteria.
The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 degrees C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na(2)S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe(3)S(4)) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 degrees C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS(2)) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials.
Gramp
Jonathan P
JP
Department of Microbiology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210, USA.
Bigham
Jerry M
JM
Jones
F Sandy
FS
Tuovinen
Olli H
OH
D018441:Biofilms; D005296:Ferrous Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D013431:Sulfates / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry; D016999:Sulfur-Reducing Bacteria / Q000378:metabolism* / Q000502:physiology; D013696:Temperature; D013997:Time Factors; D014961:X-Ray Diffraction
D005296:Ferrous Compounds; D013431:Sulfates; D013440:Sulfides; C111959:greigite; C011342:pyrite; D013455:Sulfur; D007501:Iron; C022597:ferrous sulfide