Biodiversity Of Bacteria On The Potassium-Bearing Mineral In Nanjing Longshan Mountain And Interaction Between Bacteria And Potassium-Bearing Mineral

Microbes inhabit diverse environments at and near the Earth’s surface. Their potential to cause geochemical change is immense. These microorganisms directly or indirectly affect the Earth’s geochemical environments. Research on mineral surface’s bacterial biological characteristics and their effects on the silicate mineral weathering will further understand microbial resources and diversity, clarify microbial community changes from minerals to soils and the correlation with the mineral weathering in the natural conditions. This paper also isolated mineral-solubilizing bacteria and investigated mineral-microbes interaction which would provide the theoretical and experimental bases for further understanding of mineral-microbes interaction mechamisms.Bacterial community and diversity of different weathered feldspar and soil samples were studied by16S rDNA clone libraries. The results showed that bacterial communities from the three series samples were affiliated with fourteen major groups. Proteobacteria and Acidobacteria were the most abundant groups in the clone libraries. Gemmatimonadetes were only found in the soil samples. Bacterial community composition may be related to the degree of mineral weathering. Clones from less-weathered feldspar mineral belonged to three major groups:Acidobacteria, Actinobacteria and a-Proteobacteria; Clones from more-weathered feldspar minerals belonged to four major groups:a-Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria; Clones from the soils belonged to two major groups:Acidobacteria and (3-Proteobacteria. An increasing abundance of β,δ-Proteobacteria, Firmicutes, Planctomycetes, Chloroflexi, Nitrospira, Ktedonobacteria and Verrucomicrobia were found along the weathering gradient from the weathered feldspar minerals to the soils.PCA and CCA analyses of the available element contents and the bacterial diversity index showed that the degree of mineral weathering was clearly correlation with bacterial community diversity. a-Proteobacteria, Bacteroidetes, Gemmatimonadetes were correlated with K, Ca, and Mg contents; while P-Proteobacteria, Planctomycetes, Ktedonobacteria, Firmicutes and Acidobacteria were correlated with Si, Al, Fe, and pH. Proteobacteria, Bacteroidetes and Acidobacteria played an important role in the process of mineral weathering and the elements mobilization.Sixty-three strains were isolated from different weathered feldspar and soil samples by conventional plate culture technique. ARDRA and16S rDNA sequences phylogenetic analyses indicated that the bacteria showed abundant diversity. Bacteria isolated from the soils belonged to six groups:a-, β-and y-Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes; bacteria isolated from more-weathered feldspar minerals belonged to four groups:Firmicutes, Actinobacteria, a-Proteobacteria, and Bacteroidetes; bacteria isolated from less-weathered feldspar belonged to two groups:Firmicutes and Actinobacteria. Bacteria belonging to Bacillus, Arthrobacter and Paenibacillus accounted for52.4%,19%, and11.1%, respectively.Of the sixty-three isolates, twenty-one strains have the ability of dissolving feldspar mineral compared to the control.16S rDNA sequences phylogenetic analysis indicated that mineral-solubilizing bacteria belonged to Bacillus. Paenibacillus, Arthrobacter, Flexibacter, Rhizobium, Ralstonia and Pantoea. Rhizobium, Ralstonia, Pantoea and Flexibacter were the first reported bacteria which could promote the mineral solubilization. Strain M65identified as Rhizobium sp. was very effective in enhancing feldspar dissolution.A short period flask-based and long period unflask-based experiments showed that the biotite was easier to be weathered by strains Q12and M65than feldspar. The presence of the bacteria not only promoted mineral solubilizition, but also induced mineral mineralization.The morphogeneses of strains Q12and M65were changed in the presence of feldspar and biotite minerals. The release of Fe, Ca and Al was obviously increased in the presence of stains Q12and M65. Mineral solubilization and precipitation were existed alternatively. Strain M65had two quorum signalling:luxI/luxR quorum senxing system and luxS/AI-2quorum sensing system. luxI/luxR quorum sensing system as primary autoinducers-producing allowed strain M65to control the gene expression of bioflim formation in response to changes in cell numbers. Strain Q12only had luxS/AI-2quorum sensing system. The production of autoinducers was related with cell population desity and growth state. It reached the highest production of autoinducers during the bacterial logarithm phase, and decreased significantly in the stable phase of the strains Q12and M65.