黄龙嗜冷细菌胞外琥珀酸组分对碳酸钙矿化的影响

The effects of extracellular succinic acid of psychrotrophic bacteria isolated from Huanglong on the calcification process of calcium carbonate at low temperatures

为探索黄龙钙华的生物成因,本研究以黄龙嗜冷细菌的胞外特征有机酸组分——琥珀酸为研究对象,通过模拟黄龙水体的低温沉积环境,利用X射线粉末衍射(XRD)和扫描电镜(SEM),考察了琥珀酸对钙化体系中的钙化动力学过程、碳酸钙晶型和形貌的影响。结果表明:①高浓度琥珀酸、低pH值,低温都会在一定程度上抑制碳酸钙沉积。②高浓度琥珀酸可以诱导球霰石型碳酸钙的形成;③高温促进了体系中碳酸钙微晶的聚合。综上可见,黄龙嗜冷细菌的胞外琥珀酸组分在一定程度上参与了碳酸钙的沉积过程,对晶体的晶型和形貌具有一定的调控作用。其结果可为黄龙钙华生物成因的探究提供理论基础。

In order to explore the biogenic theory of Huanglong travertine,the authors studied succinic acid,the typical extracellular organic acid of psychrotrophic bacteria isolated from Huanglong.By simulating the low-temperature sedimentary environments of Huanglong water body,the authors investigated the effects of succinic acid on the calcification kinetics as well as the morphology and polymorphism of CaCO3.Scanning electron microscope （SEM） and X-ray diffraction （XRD） were used to characterize the morphology and polymorphs of CaCO3precipitation.The results were listed as followes：① High concentration,low pH value and temperature inhibit the calcification to a certain extent.② High concentration of succinic acid induces the formation of vaterite.③ High temperature improves the aggregations of microcrystals.In conclusion,succinic acid,as the typical extracellular organic acid of Huanglong psychrotrophic bacteria,participates in the process of sedimentation to a certain extent and plays a role in regulating the morphology and polymorphism of CaCO3.The results can provide a basis for biogenic theory of Huanglong travertine.