Abstract：
Microbially induced carbonate precipitation (MICP) immobilizes toxic metals and reduces their bioavailability in aqueous systems. However, its application in the treatment of acid mine drainage (AMD) is poorly understood. In this study, the genomes of Sporosarcina sp. UB5 and UB10 were sequenced. Urease, carbonic anhydrases, and metal resistance genes were identified and enzymatic assays were performed for their validation. The geochemical mechanism of precipitation in AMD was elucidated through geo-mineralogical analysis. Sporosarcina sp. UB5 was shown to be a new genomospecies, with an average nucleotide identity < 95 % (ANI) and DNA-DNA hybridization < 70 % (DDH) whereas UB10 is close to S. pasteurii. UB5 contained two urease operons, whereas only one was identified in UB10. The ureolytic activities of UB5 and UB10 were 122.67 ± 15.74 and 131.70 ± 14.35 mM NH4+ min-1, respectively. Both strains feature several carbonic anhydrases of the α, β, or γ families, which catalyzed the precipitation of CaCO3. Only Sporosarcina sp. UB5 was able to immobilize metals and neutralize AMD. Geo-mineralogical analyses revealed that UB5 directly immobilized Fe (1-23 %), Mn (0.65-1.33 %) and Zn (0.8-3 %) in AMD via MICP and indirectly through adsorption to calcite and binding to bacterial cell walls. The MICP-treated AMD exhibited high removal rates (>67 %) for Ag, Al, As, Ca, Cd, Co, Cu, Fe, Mn, Pb, and Zn, and a removal rate of 15 % for Mg. This study provides new insights into the MICP process and its applications to AMD treatment using autochthonous strains.
摘要：
微生物诱导的碳酸盐沉淀（MICP）固定有毒金属并降低其在水性系统中的生物利用度。然而,其在酸性矿山排水（AMD）处理中的应用知之甚少。在这项研究中,孢子虫的基因组。对UB5和UB10进行测序。脲酶,碳酸酐酶，并鉴定了金属抗性基因，并进行了酶法验证。通过地质矿物学分析阐明了AMD降水的地球化学机制。孢子虫sp.UB5被证明是一种新的基因组，平均核苷酸同一性<95%(ANI)和DNA-DNA杂交<70%(DDH),而UB10接近巴氏链球菌。UB5含有两个脲酶操纵子,而在UB10中只发现了一个。UB5和UB10的尿素分解活性分别为122.67±15.74和131.70±14.35mMNH4min-1。两种菌株都具有几种α的碳酸酐酶，β,或γ家族，催化CaCO3的沉淀。只有孢子虫sp。UB5能够固定金属并中和AMD。地质矿物学分析表明，UB5直接固定了铁(1-23%)，AMD中的Mn（0.65-1.33％）和Zn（0.8-3％）通过MICP以及间接通过吸附到方解石并结合到细菌细胞壁。MICP处理的AMD表现出高的Ag去除率（>67％），Al,As,Ca,Cd,Co,Cu,Fe,Mn,Pb,Zn,对Mg的去除率为15%。这项研究提供了有关MICP过程及其在使用本地菌株进行AMD治疗中的应用的新见解。
