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The Research of Interaction between Minerals and Microbes

Author: ChengLiangJuan
Tutor: LiFuChun
School: Nanjing Agricultural College
Course: Soil
Keywords: Burkholderia. sp 8B biotite adsorption bioweathering biomineralization vermiculite montmorillonite
CLC: Q93-3
Type: Master's thesis
Year: 2009
Downloads: 66
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Abstract

Weathering of primary silicate minerals are of great importance in the explanation of soil forming process and global climate change. Microorganisms are very important in the process of mineral weathering. The Research of interaction between minerals and microbes can provide theory evidence to weathering mechanism and biomineralization.We selected biotite which is weak anti-warthering ability, layered structure aluminosilicate minerals as the representative of primary silicate minerals and Burkholderia sp. which is proved that it has weathering silicate minerals ability as the representative of microbes. We designed the experiment of interaction between minerals and microbes including adsorption, bioweathering and bacteria respond to minerals. Main results as follows:(1) We selected a bacterial strain which has weathering ability from granite weathering crust, it is Burkholderia sp. (code 8B) through colony morphology observation and 16S rDNA identification(2) The adsorption of Burkholderia sp.8B and silicate bacteria YM results show that the adsorption amount per unit area of Burkholderia sp.8B and Silicate bacteria YM were different, but both of them prefer to be adsorbed on the surface of orthoclase, and with the increase of the concentration of bacteria, the selective adsorption on orthoclase becomes more dominant.(3) In static cultured, after 110 days secondary minerals and the secondary minerals evolution of biotite from weather products (<1μm) can be found. The weathering products may were vermiculite and montmorillonite. Compared the chemical process(HCl) with the microbial process, Fe、Al and Si can be easier released by HCl, but secondary minerals from weather products can not be found. It is because of lacking microorganism, which indicated that microorganisms can help to form secondary minerals. The form of secondary minerals is schistose aggregated and spherical. The component of schistose aggregated mineral is vermiculite, form processes resemble to inherition mode. The component of spherical mineral is montmorillonite, form processes resemble to dissolution-deposition mode.(4) The existence of mineral can stimulate Burkholderia sp.8B to produce organic acid and polysaccharose. Oxalic acid was mainly found in weathering process, which can accelerately dissolve various elements from mineral. In the shake culture experiment, only K, Al, Si and Fe can be dissoluted from biotite. In the static culture experiment, after 450d, the element leaching order is K-Al, Si-Fe-Mg-Na-Ca.Our preliminary experimental results showed that Burkholderia. sp can not only accelerate weathering of biotite but also accelerate formation of secondary minerals. This can create favorable conditions using for research weathering.

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