The advantages of microbial induced carbonate mineralization for soil-stabilization and building-material industries are under extensive investigation. The pH is one of the influential parameters on the desired calcium carbonate mineralization due to the resulting textures of this mineral. Moreover, the decrease in microbial growth under the extreme alkaline environment compatible with the sustainability of concrete has been the bottleneck for an effective application of Microbial Induced Carbonate Precipitation (MICP) in the concrete industry. Microbial consortia have shown more robustness in their resistance to environmental fluctuations than pure cultures. In addition, microorganisms obtained from alkaline environments could facilitate their adaptation to extreme alkalinity. The aim of this study was to obtain urease producing bacteria (UPB) able to maintain a high MICP performance under extremely alkaline conditions compatible with concrete by adapting native microorganisms obtained from extreme environments. The growth performance, urease activity, strength of the generated biocement, and CaCO₃ mineralogy were compared with the best-performer urease-producing bacteria (UPB), S. pasteurii DSMZ 33. The native bacteria presented a similar performance in growth and urease activity than S. pasteurii under extreme alkaline conditions (pH 12.5). However, the generated biocement of native Sporosarcina sp. achieved 461 % more unconfined compressive strength (UCS) and 120 % more CaCO₃ content than the biocement generated by S. pasteurii DSMZ 33. The careful adaptation process performed in this study for native UPB and S. pasteurii DSMZ 33 is an interesting approach with promising and projectable results for future engineering and biotechnological applications. These results have important implications for the design of engineering solutions involving MICP.

Statement of Significance

A consolidated and strong biocement was generated by a native species obtained from extreme ecosystems in an effort of bioprospecting to enhance the performance of biotechnological solutions for geotechnical applications in the concrete and soil-improvement industries. Biocement generated by the native species was stronger than the generated by one of the best-described biocementation performers. This native species was able to actively growing and do perform microbial-induced-carbonate-mineralization under extreme alkalinity conditions after a careful laboratory adaptation process. The native species presented unique and differentiating traits that gave it a better adaptability and biocementation performance. The same occurs with a priceless microbial diversity inhabiting little explored and unprotected extreme ecosystems. Extreme environments house a fascinating biodiversity with potential value for ecosystem services.

中文翻译：

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在土壤和改良土壤的极端碱性条件下，具有增强微生物诱导的碳酸钙生物矿化性能的本地细菌

微生物引起的碳酸盐矿化在土壤稳定和建材行业中的优势正在广泛研究中。由于该矿物的最终质地，pH是所需碳酸钙矿化的影响参数之一。而且，在与混凝土的可持续性相容的极端碱性环境下微生物生长的减少一直是微生物诱导的碳酸盐沉淀（MICP）在混凝土工业中有效应用的瓶颈。与纯培养物相比，微生物群落对环境波动的抵抗力更强。另外，从碱性环境获得的微生物可以促进其适应极端碱性。这项研究的目的是通过适应从极端环境获得的天然微生物，获得能够在与混凝土相容的极端碱性条件下保持高MICP性能的产生脲酶的细菌（UPB）。生长性能，脲酶活性，生成的生物水泥的强度和CaCO_将3种矿物学与表现最佳的产脲酶的细菌S. pasteurii DSMZ 33进行了比较。在极端碱性条件（pH 12.5）下，天然细菌在生长和脲酶活性方面的表现与巴斯德毕赤酵母相似。然而，天然孢子菌属sp的产生的生物水泥。比巴氏酵母DSMZ 33产生的生物水泥获得的无侧限抗压强度（UCS）提高了461％，CaCO ₃含量提高了120％。在这项研究中，对天然UPB和巴氏酵母进行了谨慎的适应过程DSMZ 33是一种有趣的方法，可为将来的工程和生物技术应用提供有希望的和可预测的结果。这些结果对涉及MICP的工程解决方案的设计具有重要意义。

重要声明

为了增强混凝土和土壤改良行业中岩土工程应用的生物技术解决方案的性能，生物勘探工作从极端生态系统中获得了本地物种，从而产生了坚固而坚固的生物水泥。由天然物种产生的生物水泥比由描述得最好的生物水泥执行者之一产生的生物水泥更强。经过仔细的实验​​室适应过程后，该本地物种能够活跃生长并在极端碱度条件下进行微生物诱导的碳酸盐矿化。本地物种表现出独特且与众不同的特征，使其具有更好的适应性和生物胶凝性能。对于无价的微生物多样性，几乎没有探索和未保护的极端生态系统，情况也是如此。