The Dynamic Change Of The Species And Morphologies Of The Carbonate Minerals In SN-1Strain Culture

Carbonate mineral is one of the most abundant minerals on the earth. Carbonate mineral and carbonate rock from microbial metabolism exist widely in nature. First, biology absorbs’elements from the surrounding environment selectively, and then functionalize carbonate structures are assembled successfully under biological control. Biology can also induce or involve the formation of carbonate minerals by metabolism change of its surrounding environment.Summary of the species, compositions and the dynamic change law of morphologies in the presence of microbes is the key to understand the formation mechanism of carbonate mineral.Cultureal experiments of carbonate precipitation within100days were designed and completed under the mediation of bacteria of clostridium sp. at different stages. HPLC, XRD, ICP-OES and SEM/EDS were used to determine the changes of solution and observe species and morphologies of minerals. The main results are as follows:(1) The change trend of carbonate mineral assemblages was calciteâ†'calcite and monohydrocalciteâ†'monohydrocalcite and calciteâ†'monohydrocalcite along with the increased experimental times; While the contrary results were observed in the control experiments.(2) The contents of MgCO3in experimental groups were higher than the control ones. Mg2+was more easily to enter calcite lattice in the presence of Clostridium indicating that organic matter secretioned by microbial metabolism might be integrated into the minerals, so that it was the possible reasons for instability monohydrocalcite exist stably.(3) In Clostridium sp. culture the change trend of carbonate mineral morphology was: rodâ†'dumbbellâ†'cauliflowerâ†'spherulite. The dumbbell minerals might inherit the morphological characteristics of the cells, while spherical minerals might be the final morphology. The dumbbell mineral high-magnesium calcite, while the spherical mineral monohydrocalcite. (4) The depositation rate has a positive correlation with both concentration bacteria and polysaccharide concentration correlated positively, with correlation coefficients of0.50and0.51respetively. Sedimentation rate and pH value was a negative correlation, with correlation coefficient of0.55. Comprehensive analysis suggest that the sedimentation rate was mainly determined by the concentration of bacteria, and other factors may play an indirect role.