Mechanical and Industrial Engineering Department, Montana State University, Bozeman, Montana 59717, United States.
Civil and Environmental Engineering Department, Montana State University, Bozeman, Montana 59717, United States.
ACS Appl Mater Interfaces. 2024 Jan 17;16(2):2075-2085. doi: 10.1021/acsami.3c13971. Epub 2024 Jan 4.
Microbially induced calcium carbonate precipitation (MICP) has emerged as a novel technology with the potential to produce building materials through lower-temperature processes. The formation of calcium carbonate bridges in MICP allows the biocementation of aggregate particles to produce biobricks. Current approaches require several pulses of microbes and mineralization media to increase the quantity of calcium carbonate minerals and improve the strength of the material, thus leading to a reduction in sustainability. One potential technique to improve the efficiency of strength development involves trapping the bacteria on the aggregate surfaces using silane coupling agents such as positively charged 3-aminopropyl-methyl-diethoxysilane (APMDES). This treatment traps bacteria on sand through electrostatic interactions that attract negatively charged walls of bacteria to positively charged amine groups. The APMDES treatment promoted an abundant and immediate association of bacteria with sand, increasing the spatial density of ureolytic microbes on sand and promoting efficient initial calcium carbonate precipitation. Though microbial viability was compromised by treatment, urea hydrolysis was minimally affected. Strength was gained much more rapidly for the APMDES-treated sand than for the untreated sand. Three injections of bacteria and biomineralization media using APMDES-treated sand led to the same strength gain as seven injections using untreated sand. The higher strength with APMDES treatment was not explained by increased calcium carbonate accrual in the structure and may be influenced by additional factors such as differences in the microstructure of calcium carbonate bridges between sand particles. Overall, incorporating pretreatment methods, such as amine silane coupling agents, opens a new avenue in biomineralization research by producing materials with an improved efficiency and sustainability.
微生物诱导碳酸钙沉淀（MICP）作为一种新技术，具有通过低温过程生产建筑材料的潜力。MICP 中碳酸钙桥的形成允许生物胶结聚合颗粒，从而产生生物砖。目前的方法需要多次微生物和矿化介质脉冲来增加碳酸钙矿物的数量并提高材料的强度，从而降低了可持续性。一种提高强度发展效率的潜在技术是使用硅烷偶联剂（如带正电荷的 3-氨丙基甲基二乙氧基硅烷（APMDES））将细菌困在聚合体表面上。这种处理方法通过静电相互作用将细菌困在沙子上，吸引带负电荷的细菌壁到带正电荷的胺基上。APMDES 处理促进了细菌与沙子的大量立即结合，增加了沙中脲酶微生物的空间密度，并促进了初始碳酸钙的有效沉淀。尽管微生物的生存能力因处理而受到影响，但尿素水解的影响最小。经 APMDES 处理的沙子的强度增加速度比未经处理的沙子快得多。用 APMDES 处理过的沙子进行三次细菌和生物矿化介质注射，可获得与未处理沙子进行七次注射相同的强度增加。APMDES 处理的高强度不是通过结构中碳酸钙的增加来解释的，可能受到其他因素的影响，例如沙粒之间碳酸钙桥的微观结构差异。总的来说，通过使用胺硅烷偶联剂等预处理方法，为生物矿化研究开辟了新途径，生产出具有更高效率和可持续性的材料。
