Biogeochemical Changes During Bio-cementation Mediated by Stimulated and Augmented Ureolytic Microorganisms
Biogeochemical Changes During Bio-cementation Mediated by Stimulated and Augmented Ureolytic Microorganisms
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DOI：
10.1038/s41598-019-47973-0
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发表时间：
2019-08-08
影响因子：
4.6
通讯作者：
Nelson, Douglas C.
中科院分区：
文献类型：
--
作者：
Gomez, Michael G.;Graddy, Charles M. R.;Nelson, Douglas C.
微生物诱导方解石沉淀是一种生物介导的胶结过程，通过方解石的沉淀改善颗粒土的工程性质。这一过程是由含有尿素酶的土壤微生物实现的，这种酶能水解尿素，并使碳酸盐离子能够用于降水。虽然大多数研究人员已经注射了非天然解脲细菌来完成生物胶结，但浓缩天然解脲微生物可能会降低工艺处理成本和对环境的影响。在这项研究中，通过两个直径1.7米的储水池的大规模生物胶结实验和补充土柱实验，研究了天然和增强(巴氏芽孢杆菌)溶脲微生物介导的生物胶结的生物地球化学差异。尽管不同方法处理后方解石的分布和工程性质相似，但本研究的结果表明，原生和增强微生物群落之间尿素分解速率和相关沉淀率的显著差异可能会影响生物胶结作用、溶液生物地球化学变化和沉淀物微结构的时间进程和空间分布。探讨了尿素水解在注射处理后通过持续过饱和使方解石沉淀的作用。
Microbially Induced Calcite Precipitation (MICP) is a bio-mediated cementation process that can improve the engineering properties of granular soils through the precipitation of calcite. The process is made possible by soil microorganisms containing urease enzymes, which hydrolyze urea and enable carbonate ions to become available for precipitation. While most researchers have injected non-native ureolytic bacteria to complete bio-cementation, enrichment of native ureolytic microorganisms may enable reductions in process treatment costs and environmental impacts. In this study, a large-scale bio-cementation experiment involving two 1.7-meter diameter tanks and a complementary soil column experiment were performed to investigate biogeochemical differences between bio-cementation mediated by either native or augmented (Sporosarcina pasteurii) ureolytic microorganisms. Although post-treatment distributions of calcite and engineering properties were similar between approaches, the results of this study suggest that significant differences in ureolysis rates and related precipitation rates between native and augmented microbial communities may influence the temporal progression and spatial distribution of bio-cementation, solution biogeochemical changes, and precipitate microstructure. The role of urea hydrolysis in enabling calcite precipitation through sustained supersaturation following treatment injections is explored.