Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, USA.
Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA.
J Appl Microbiol. 2019 Nov;127(5):1479-1489. doi: 10.1111/jam.14384. Epub 2019 Aug 19.
Development of biomineralization technologies has largely focused on microbially induced carbonate precipitation (MICP) via Sporosarcina pasteurii ureolysis; however, as an obligate aerobe, the general utility of this organism is limited. Here, facultative and anaerobic haloalkaliphiles capable of ureolysis were enriched, identified and then compared to S. pasteurii regarding biomineralization activities.
Anaerobic and facultative enrichments for haloalkaliphilic and ureolytic micro-organisms were established from sediment slurries collected at Soap Lake (WA). Optimal pH, temperature and salinity were determined for highly ureolytic enrichments, with dominant populations identified via a combination of high-throughput SSU rRNA gene sequencing, clone libraries and Sanger sequencing of isolates. The enrichment cultures consisted primarily of Sporosarcina- and Clostridium-like organisms. Ureolysis rates and direct cell counts in the enrichment cultures were comparable to the S. pasteurii (strain ATCC 11859) type strain.
Ureolysis rates from both facultatively and anaerobically enriched haloalkaliphiles were either not statistically significantly different to, or statistically significantly higher than, the S. pasteurii (strain ATCC 11859) rates. Work here concludes that extreme environments can harbour highly ureolytic active bacteria with potential advantages for large scale applications, such as environments devoid of oxygen.
The bacterial consortia and isolates obtained add to the possible suite of organisms available for MICP implementation, therefore potentially improving the economics and efficiency of commercial biomineralization.
生物矿化技术的发展主要集中在通过巴氏芽孢杆菌脲酶诱导的微生物诱导碳酸钙沉淀（MICP）上；然而，由于它是一种需氧菌，该生物体的一般用途受到限制。在这里，能够进行脲酶水解的兼性和厌氧嗜盐菌被富集、鉴定，并与巴氏芽孢杆菌在生物矿化活性方面进行了比较。
从 Soap Lake（WA）采集的沉积物悬浮液中建立了耐盐和兼性耐盐嗜碱微生物的厌氧和兼性富集物。确定了高度脲酶水解富集物的最佳 pH、温度和盐度，通过高通量 SSU rRNA 基因测序、克隆文库和分离物的 Sanger 测序相结合，确定了优势种群。富集培养物主要由芽孢杆菌和梭菌样生物组成。在富集培养物中的脲酶水解率和直接细胞计数与巴氏芽孢杆菌（菌株 ATCC 11859）的标准菌株相当。
来自兼性和厌氧富集的嗜盐菌的脲酶水解率与巴氏芽孢杆菌（菌株 ATCC 11859）的速率要么没有统计学上的显著差异，要么统计学上显著更高。本研究的结论是，极端环境可以容纳具有高脲酶活性的细菌，这些细菌具有大规模应用的潜在优势，例如在缺氧环境中。
获得的细菌共生体和分离物增加了可能用于 MICP 实施的生物组合，从而可能提高商业生物矿化的经济性和效率。
