Arthrobacter Sp. Strain MF-2 Induces High-Mg Calcite Formation: Mechanism and Implications for Carbon Fixation
Arthrobacter Sp. Strain MF-2 Induces High-Mg Calcite Formation: Mechanism and Implications for Carbon Fixation
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节杆菌属
DOI：
10.1080/01490451.2016.1155002
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发表时间：
2017-01-01
影响因子：
2.3
通讯作者：
Liu, Lu
中科院分区：
文献类型：
--
作者：
Xu, Qinglong;Zhang, Chonghong;Liu, Lu
为了更好地了解微生物形成碳酸盐矿物的机理，对节杆菌进行了培养实验。菌株MF-2在不含碳酸盐离子的M2培养基上培养50d。同时进行了一系列无菌对照实验。测定细胞密度、沉淀量、胞外多糖(EPS)含量、碳酸酐酶(CA)活性、低分子有机酸浓度、pH值、电导率以及培养液中的钙、镁离子浓度。用扫描电子显微镜观察了碳酸盐沉淀物的形貌，用X射线衍射法测定了碳酸盐的矿物种类。结果表明，随着培养时间的延长，生物实验中沉淀物的数量逐渐增加，而非生物实验中没有得到沉淀物。平均沉淀率与细胞密度和EPS含量呈正相关，相关系数分别为0.64和0.61。这表明细菌细胞和EPS对碳酸盐的沉淀有影响。碳酸盐离子进入矿物是二氧化碳水合作用的结果，细菌微生物分泌CA促进了碳酸盐离子进入矿物中。这些发现有助于不断寻找在地下封存二氧化碳的可行机制，在这种情况下，二氧化碳是由微生物介导的。
To better understand the mechanism of formation of carbonate minerals by microbes, culture experiments with Arthrobacter sp. strain MF-2 were carried out using M2 medium without carbonate ions for 50days. A series of sterile control experiments without bacteria were run simultaneously. During the incubation, cell density, the quantity of precipitate, the extracellular polysaccharide (EPS) content, the activity of carbonic anhydrase (CA), the low molecular weight organic acid concentration, the pH, the electrical conductivity, and the Ca2+ and Mg2+ concentrations of the medium were determined. The morphologies of the precipitated carbonates were observed using scanning electron microscopy, and their mineral species were determined by X-ray diffraction. The results demonstrated that the quantity of precipitate in the biotic experiments increased gradually with the incubation time; precipitate was not obtained in the abiotic experiments. The average precipitation rate correlated positively with the cell density and the EPS content, with r = 0.64 and 0.61, respectively. This suggests that bacterial cells and EPS effected carbonate precipitation. Carbonate ion incorporation into minerals results from carbon dioxide hydration, promoted by microbial secretion of CA by bacteria. These findings contribute to the ongoing search for feasible mechanisms for the sequestration of carbon dioxide in the subsurface, in this case mediated by microorganisms.