17:00 〜 17:15
[SMP49-04] 走査型透過X線顕微鏡(STXM)の微生物－鉱物相互作用解明への応用
キーワード：走査型透過X線顕微鏡, パイライト, バイオリーチング
Microorganisms in the environment critically impact global geochemical cycles and redox reactions of various elements. Many geochemically important redox reactions (e.g., sulfate reduction, Fe(II) oxidation) are largely associated with microbial activity. In addition, microbes can mediate both mineral formation (biomineralization) and mineral dissolution (bioleaching). Recent studies suggest a significant relationship between Fe(II)-oxidizing bacteria and ancient Banded Iron Formation, one of the large geochemical events in Earth's history. The general ecological importance of environmental microbial reaction has been well recognized; however, the specific mechanisms of the reactions in the environments such as the reaction rate and spatial dynamics are poorly understood. In the environment such as sediments, microbial reactions and habitability vary locally and form complicated geochemical networks, which makes it difficult to characterize the specific biogenic reactions in detail. Scanning transmission X-ray microscopy (STXM), which uses near-edge X-ray absorption spectroscopy (NEXAFS) is a powerful new tool that can be applied to hydrated biological materials with high spatial resolution. The STXM provides spatial resolution of better than 50 nm, which is suitable for imaging bacteria and bacterial biofilms. In the present study, we applied the STXM into the bioleaching of sulfide mineral (pyrite) to determine carbon, oxygen, and iron species in nano-scale. Both metal and biogenic organic materials in pyrite-microbe interface were investigated in the single cell level. Our study shows that the STXM could be a potential technique to provide direct information on specific biogenic reaction microorganism.