Title: Serpentine Dissolution in the Presence of Bacteria<i>Bacillus mucilaginosus</i>
Abstract: Abstract Dissolution of serpentine in the presence of soil bacteria Bacillus mucilaginosus is examined through solution chemistry analysis, X-ray diffraction and 3D X-ray microscopy. Microbe-mineral interactions were carried out by incubating serpentine powder and the bacteria for 30 days. Measured Mg concentrations in the culture media were significantly higher than that in any of the control experiments at any time during the experiments. However, the behavior of the Mg/Si ratio was similar to what was known for inorganic dissolution of silicate minerals. XRD analysis revealed increased quantity of amorphous components in the reacted mineral samples, and tomography images showed a very porous and powdered appearance of the dissolved serpentine grains. These data suggest the dissolution probably proceeds through an incongruent route. Further, these observations imply that there is little genetic control by the microbes during the bacteria-mineral interaction; rather, the accelerated dissolution results primarily from a biologically induced process. Finally, the observed pH decrease, the presence of carboxylic acid, ketone, aldehyde, phenol, and alcohol in the metabolites suggests that organic acids and ligands secreted by the bacteria are largely responsible for the accelerated mineral dissolution. Keywords: Bacillus mucilaginosus serpentineweathering processmechanism3D image Acknowledgments This research was jointly supported by National Natural Science Foundation of China (Grant No. 40773069), National Science Foundation for Creative Research Groups (Grant No. 41021062), and Hundred Talents' Program of Chinese Academy of Sciences. The authors are grateful to Dr. Hong Zhong of Institute of Geochemistry, Chinese Academy of Sciences for providing mineral samples, and X-ray microscope beamline U7A of National Synchrotron Radiation Laboratory, University of Science and Technology of China for three-dimensional (3D) shapes captured, and Yong Guan and Wenjie Li in there for their assistance in this work.
Publication Year: 2012
Publication Date: 2012-11-08
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 31
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