Seidel Michael, Hamley-Bennett Charlotte, Reeksting Bianca J, Bagga Manpreet, Hellmann Lukas, Hoffmann Timothy D, Kraemer Christiane, Ofiţeru Irina Dana, Paine Kevin, Gebhard Susanne
Institut für Molekulare Physiologie, Johannes-Gutenberg-Universität Mainz, Mainz, Germany.
Department of Life Sciences, Milner Centre for Evolution, University of Bath, Bath, UK.
Environ Microbiol. 2025 Apr;27(4):e70093. doi: 10.1111/1462-2920.70093.
Microbially induced calcite precipitation (MICP) offers promising solutions for sustainable, low-cement infrastructure materials. While it is known how urea catabolism leads to biomineralisation, the non-ureolytic pathways of MICP are less clear. This limits the use of the latter in biotechnology, despite its clear benefit of avoiding toxic ammonia release. To address this knowledge gap, the present study explored the interdependence between carbon source utilisation and non-ureolytic MICP. We show that acetate can serve as the carbon source driving calcite formation in several environmental Bacillaceae isolates. This effect was particularly clear in a Solibacillus silvestris strain, which could precipitate almost all provided calcium when provided with a 2:1 acetate-to-calcium molar ratio, and we show that this process was independent of active cell growth. Genome sequencing and gene expression analyses revealed an apparent link between acetate catabolism and calcite precipitation in this species, suggesting MICP may be a calcium stress response. Development of a simple genetic system for S. silvestris led to the deletion of a proposed calcium binding protein, although this showed minimal effects on MICP. Taken together, this study provides insights into the physiological processes leading to non-ureolytic MICP, paving the way for targeted optimisation of biomineralisation for sustainable materials development.
微生物诱导碳酸钙沉淀（MICP）为可持续的低水泥基础设施材料提供了有前景的解决方案。虽然已知尿素分解代谢如何导致生物矿化，但MICP的非尿素分解途径尚不清楚。这限制了后者在生物技术中的应用，尽管其具有避免释放有毒氨的明显优势。为了填补这一知识空白，本研究探讨了碳源利用与非尿素分解MICP之间的相互依存关系。我们表明，乙酸盐可以作为碳源，驱动几种环境芽孢杆菌科分离株中的方解石形成。这种效应在一株森林独芽孢杆菌中尤为明显，当提供2:1的乙酸盐与钙的摩尔比时，该菌株几乎可以沉淀所有提供的钙，并且我们表明这个过程与活跃的细胞生长无关。基因组测序和基因表达分析揭示了该物种中乙酸盐分解代谢与方解石沉淀之间的明显联系，表明MICP可能是一种钙应激反应。为森林独芽孢杆菌开发的一个简单遗传系统导致了一个假定的钙结合蛋白的缺失，尽管这对MICP的影响最小。综上所述，本研究深入了解了导致非尿素分解MICP的生理过程，为有针对性地优化生物矿化以实现可持续材料开发铺平了道路。
