梭菌MH18 菌株诱导碳酸盐矿物的形成

【目的】研究细菌作用下碳酸盐矿物的形成过程有助于了解微生物成矿的机理。【方法】在LagoaVermelha培养基中(Mg/Ca为6:1)对一株分离自土壤样品的梭菌MH18菌株进行了为期35天的碳酸盐矿物培养实验,同时还完成了一组无菌对照实验。利用X-射线衍射技术对沉淀物的矿物成分进行了测定,利用光学显微镜和扫描电子显微镜对沉淀物的形态进行了系统的观察。【结果】MH18菌株在Lagoa Vermelha培养基中诱导形成了以高镁方解石为主的碳酸盐矿物;这些矿物起初具有哑铃状的外形,后来发展为球状;无菌对照实验中出现少量沉淀物,但X-射线衍射技术图谱显示它们是非晶态物质。【结论】MH18菌株具有促进碳酸盐矿物结晶的功能;碳酸盐矿物的特殊形态(哑铃状和球状)可能与细菌形态存在着某种成因上的联系。

Clostridium sp.MH18 strain induces the formation of carbonate minerals

[Objective]We studied the formation of carbonate minerals by bacteria to understand the mechanism of microbial mineralization.[Methods]Cultures of carbonate precipitation using Lagoa Vermelha medium with 6:1 molar ratio of Mg/Ca within 35 days were made under the mediation of Clostridium sp.(MH18 strain) isolated from soil.At the same time,aseptic experiments without the inoculation were done as the control.Mineral species were determined by X-ray diffraction,and the morphologies of precipitated carbonates were observed using optical microscopy and scanning electron microscopy.[Results]In the LV medium,MH18 strain mediated the formation of carbonate mineral,in which high-magnesium calcite was dominant.In the initial stage,the minerals had shapes with dumbbell-like morphology,and finally transformed to spheres.Only a small amount of precipitation appeared in the control,but X-ray diffraction patterns showed that these precipitations were amorphous substance.[Conclusions]MH18 strain could induce crystallization of carbonate.