Microbially induced calcite precipitation (MICP) has not only helped to shape our planet’s geological features but is also a promising technology to address environmental concerns in civil engineering applications. However, limited understanding of the biomineralization capacity of environmental bacteria impedes application. We therefore surveyed the environment for different mechanisms of precipitation across bacteria. The most fundamental difference was in ureolytic ability, where urease-positive bacteria caused rapid, widespread increases in pH, whereas nonureolytic strains produced such changes slowly and locally. These pH shifts correlated well with patterns of precipitation on solid medium. Strikingly, while both mechanisms led to high levels of precipitation, we observed clear differences in the precipitate. Ureolytic bacteria produced homogenous, inorganic fine crystals, whereas the crystals of nonureolytic strains were larger and had a mixed organic/inorganic composition. When representative strains were tested in application for crack healing in cement mortars, nonureolytic bacteria gave robust results, while ureolytic strains showed more variation. This may be explained by our observation that urease activity differed between growth conditions or by the different natures and therefore different material performances of the precipitates. Our results shed light on the breadth of biomineralization activity among environmental bacteria, an important step toward the rational design of bacterially based engineering solutions.

IMPORTANCE Biomineralization triggered by bacteria is important in the natural environment and has many applications in industry and in civil and geotechnical engineering. The diversity in biomineralization capabilities of environmental bacteria is, however, not well understood. This study surveyed environmental bacteria for their ability to precipitate calcium carbonate minerals and investigated both the mechanisms and the resulting crystals. We show that while urease activity leads to the fastest precipitation, it is by no means essential. Importantly, the same quantities of calcium carbonate are produced by nonureolytic bacteria, and the resulting crystals appear to have larger volumes and more organic components, which are likely beneficial in specific applications. Testing both precipitation mechanisms in a self-healing concrete application showed that nonureolytic bacteria delivered more robust results. Here, we performed a systematic study of the fundamental differences in biomineralization between environmental bacteria, and we provide important information for the design of bacterially based engineering solutions.

微生物引起的方解石沉淀（MICP）不仅有助于塑造我们星球的地质特征，而且还是一项有前途的技术，可以解决土木工程应用中的环境问题。但是，对环境细菌生物矿化能力的了解有限，阻碍了其应用。因此，我们调查了环境中各种细菌沉淀的不同机制。最根本的区别是在尿素分解能力上，其中脲酶阳性细菌引起pH值迅速而广泛的增加，而非尿素分解菌株则缓慢而局部地产生这种变化。这些pH值的变化与固体培养基上的沉淀模式密切相关。令人惊讶的是，尽管两种机制均导致高水平的降水，但我们观察到了明显的降水差异。溶尿细菌产生均质的无机细晶体，而非溶尿菌株的晶体更大，并具有混合的有机/无机成分。当测试代表性的菌株在水泥砂浆中的裂缝愈合中的应用时，非脲解细菌给出了可靠的结果，而脲解菌株表现出更大的变异性。这可以通过我们的观察来解释，脲酶活性在生长条件之间或由于不同的性质以及因此沉淀物的不同材料性能而不同。我们的结果揭示了环境细菌中生物矿化活性的广度，这是对基于细菌的工程解决方案进行合理设计的重要一步。非脲解菌株的晶体较大，并且具有混合的有机/无机成分。当测试代表性的菌株在水泥砂浆中的裂缝愈合中的应用时，非脲解细菌给出了可靠的结果，而脲解菌株表现出更大的变异性。这可以通过我们的观察来解释，脲酶活性在生长条件之间或由于不同的性质以及因此沉淀物的不同材料性能而不同。我们的结果揭示了环境细菌中生物矿化活性的广度，这是对基于细菌的工程解决方案进行合理设计的重要一步。非脲解菌株的晶体较大，并且具有混合的有机/无机成分。当测试代表性的菌株在水泥砂浆中的裂缝愈合中的应用时，非脲解细菌给出了可靠的结果，而脲解菌株表现出更大的变异性。这可以通过我们的观察来解释，脲酶活性在生长条件之间或由于不同的性质以及因此沉淀物的不同材料性能而不同。我们的结果揭示了环境细菌中生物矿化活性的广度，这是合理设计基于细菌的工程解决方案的重要一步。这可以通过我们的观察来解释，尿素酶的活性在生长条件之间或由于不同的性质以及因此沉淀物的不同材料性能而有所不同。我们的结果揭示了环境细菌中生物矿化活性的广度，这是对基于细菌的工程解决方案进行合理设计的重要一步。这可以通过我们的观察来解释，尿素酶的活性在生长条件之间或由于不同的性质以及因此沉淀物的不同材料性能而有所不同。我们的结果揭示了环境细菌中生物矿化活性的广度，这是对基于细菌的工程解决方案进行合理设计的重要一步。

重要性细菌引发的生物矿化在自然环境中很重要，在工业，土木和岩土工程中有许多应用。然而，人们对环境细菌的生物矿化能力的多样性了解甚少。这项研究调查了环境细菌沉淀碳酸钙矿物质的能力，并研究了机制和生成的晶体。我们表明，虽然脲酶活性导致最快的沉淀，但这绝不是必需的。重要的是，非尿素分解细菌会产生相同量的碳酸钙，并且所得晶体似乎具有更大的体积和更多的有机成分，这在特定应用中可能是有益的。在自修复混凝土应用中测试这两种沉淀机理表明，非脲分解细菌可提供更可靠的结果。在这里，我们对环境细菌之间生物矿化的基本差异进行了系统的研究，并为基于细菌的工程解决方案的设计提供了重要信息。