Isolation And Purification Of Mn(â…¡)-oxidizing Bacteria In Soil And Their Oxidation Of Mn(â…¡)

Manganese(â…£) oxides,one of the most active oxides and sediment in the soil,are the products during the soil evolution and substance circulation.Studies on cause of formation and characteristic about biogenic Mn oxides are mostly focucs on sea facies Manganese(â…£) sediment,but the soil environment in land facies are different from that in the sea,especially on the biology formation process and mechanism of Manganese(â…£) oxides.In this thesis,Iron-manganese nodules and cutans which exist in brown-red soil and yellow-brown soil of WuHan city were chosen as the study objects,the Mn(â…¡)-oxidizing bacteria was separated and sublimated,besides the physiology characteristic of Mn(â…¡)-oxidizing bacteria and the oxygenation on Mn(â…¡) were discussed. The main achievements of this study are listed below:1) From the different sources of soil samples,18 species well grown bacteria of manganese tolerance type have been isolated.Then,repeat screening was carried out. hn11 and hn23 were obtained as the strongest Mn(â…¡)-oxidizing bacteria.The physiological biochemistry and molecular identification result indicated that hn11 and the Micrococcus roseus belongs to the same species,and so are the same situation to hn23 and the Bacillus mucilaginosus.In addition,hn11 was isolated from iron-manganese nodule,hn23 was isolated from cutan;2) The detection of growth curve within different Mn(â…¡)-oxidizing bacterias in three different mediums(L2,LB,2×BYG),indicated that the most suitable medium for Mn(â…¡)-oxidizing bacteria to oxidation is LB;3) The logarithmic growth phase,Stationary phase and deterioration stage of growth curve of Mn(â…¡)-oxidizing bacteria were delayed owing to the addition of Mn(â…¡) to LB;4) The speed of of Mn(â…¡)-oxidizing bacteria adsorp or oxidize to Mn(â…¡) will be achieved to the maximum when the bacteria is staying in the logarithmic growth phase;5) At the condition of 30℃,as the Mn(â…¡) is being oxygenated constantly,the pH of the liquid medium is increasing at the same time,and the cultivate on LB(10mM)medium is more obvious than cultivate on LB medium; 6) Only 0.36 nm peak,which is a characteristic diffract peak ofδ-MnO2, appeared in the XRD patterns of products of Mn²⁺ oxidation by four bacterias, indicating that no other impure mineral but poor crystal MnO₂ were obtained;7) SEM images of the oxidation products are shown in the Figures.The products of hn11 have a thin and random stacked platy morphology.The products of hn23 have a particle morphology with a size of 0.5-5μm.The wh4 contains both random stacked and particle shaped crystallites,the products of gy16 are particles with a size of 0.2-3μm.