南方湿热区产脲酶菌固化海砂的碳酸钙结晶效果研究

从南方湿热区自然环境中分离得到一株产脲酶矿化菌，并将其高产突变株应用到海砂室内MICP灌浆试验，结合扫描电子显微镜（SEM）、能谱仪（EDS）、拉曼（Raman）对固化后的产物进行细观形貌观测。通过分析碳酸钙的形貌、尺寸、空间分布、结晶状态等基本特征现象，初步探究南方湿热区产脲酶菌在碳酸钙结晶生长方面的调控作用及其固化土体的作用效果。结果表明：南方湿热区产脲酶菌固化土体具有可行性，但碳酸钙晶体形貌并不均一，晶体晶化过程、生物调控作用及土体结构均会对碳酸钙的生成情况造成影响；碳酸钙从无序到有序、分散到聚集、不稳定到稳定，最终生长聚集为完整的结构，在生长空间充足的环境下，碳酸钙更倾向于形成聚集体。研究结论可为进一步研究不同产脲酶菌诱导碳酸钙沉淀的作用过程与调控机制提供借鉴与参考。

Study on the Crystallization Phenomenon of Calcium Carbonate forSoil Treatment with a Urease-producing Bacteria SpeciesIsolated from a Hot and Humid Region of South China

A new urease-producing bacteria was isolated from the natural environment in the southern humid and hot area of China, and its high-yielding mutant strain was applied to the sea sand indoor MICP grouting test. To study the crystallization phenomenon of calcium carbonate, the Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), and Raman were used to observe the microstructure of the treated samples. By analyzing the basic characteristics of calcium carbonate, such as the morphology, size, spatial distribution, and crystalline state, the regulatory effect on the growth of calcium carbonate crystals and the effect of solidifying soil of the urease-producing bacterial were initially explored. The results show that it is feasible to solidify the soil with urease-producing bacteria in the southern hot and humid area, but the morphology of calcium carbonate crystals is not uniform. The crystal crystallization process, biological regulation and soil structure will all affect the formation of calcium carbonate. In addition, the crytallization of calcium carbonate is from disorder to order, dispersion to aggregation, unstable to stable, and the calcium carbonate eventually develops into a complete and large aggregates in an environment with sufficient growth space. Conclusions in this paper can be used as reference for further study on the action process and regulation mechanism of calcium carbonate precipitation induced by different urease-producing bacteria.