Biodiversity Of Bacterium On The Mica Mineral Surfaces And The Mechanism Of Mineral Solution

Microorganisims are the earlist life forms on the planet, they are widely distributed on the near-surface or surface of the earth, their potential to cause geochemical change is immense, and they directly or indirectly affect the Earth’geochemical environments, the interaction between microorganism and the mineral is the universal geological process in the earth. Research on mineral surface’s bacterial population diversity will clarify microbial community change from minerals to soils and the correlation with the mineral weathering in the natural conditions. Further study of solubilizing mineral by bacteria helps to deepen understanding of mineral weathering, rich in species of mineral-solubilizing bacterial library. And it also provides theoretical basis for the further development of bio-fertilizer.In this study, the mineral of different weathering degree and soil samples were collected from mica schist area on FengHuo hill in LiangTin town, SuSong, An Hui. Then physical and chemical properties of the samples were analyzed by methods of SEM, XRD, et al. The results show that there are significant difference in weathering degree and physical and chemical properties. The results of PCR-DGGE experiments revealed that the bacterial populations structure have changed from the rock to the soil samples. With increasing degree of weathering of the samples, the bacterial diversity in the samples shows an increasing trend. Compared with the low-weathered mineral samples, high-weathered and soil samples have a higher bacterial diversity.Total129cultured bacteria were isolated from different weathering degree of rock and soils samples. The ability of solubilizing mineral by the bacterial was determined. The results showed that more-weathered rock and soil samples have higher proportion of mineral-solubilizing bacteria than less-weathered mineral samples. The paper research the biodiversity of mineral-solibilizing bacteria through phylogenetic analysis based on16S rDNA sequence analysis and showed that all mineral-solibilizing bacteria belong to Arthrobacte, Rhodococcus, Leifsonia, Bacillus, Paenibacillus, Ochrobactrum, Burkholderia, Ralstonia, Acinetobacter, Pantoea, Rhizobium, Mycobacterium and Staphylococcus generas of5different phyla:Actinobacteria, Firmicutes, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. So the mineral-solibilizing bacteria have significant species and community structural diversity. Burkholderia is the dominant population of the mineral-solibilizing bacteria. Besides, Ochrobactrum and Microbaterium are the first reported for their strong ability of weathering silicate mineral.Three bacterial strains were picked out as the tested strains for further study. A20day shake flask experiment was carried out for the study of silicate weathering. The results of the experiment showed that there is a positive correlation between the mineral solubilization and the production of organic acids by bacteria. Strains B35and C1can produce organic acids and strains B35produce more organic acids than strain C1, however, strain A41can hardly produce acids. The results of element dissolution experiment show that the order of silicate weathering by bacteria is B35>C1>A41. It might indicate that the organic acids produced by the strains in the metabolic process may be responsible for the mineral weathering.