Department of Civil and Environmental Engineering, School of Engineering, Shiraz University, Zand Street, Shiraz, 71348-51156, Iran.
Institute of Biotechnology, Shiraz University, Shiraz, Iran.
Sci Rep. 2023 Apr 10;13(1):5845. doi: 10.1038/s41598-023-33070-w.
The detrimental effects of sand storms on agriculture, human health, transportation network, and infrastructures pose serious threats in many countries worldwide. Hence, wind erosion is considered a global challenge. An environmental-friendly method to suppress wind erosion is to employ microbially induced carbonate precipitation (MICP). However, the by-products of ureolysis-based MICP, such as ammonia, are not favorable when produced in large volumes. This study introduces two calcium formate-bacteria compositions for non-ureolytic MICP and comprehensively compares their performance with two calcium acetate-bacteria compositions, all of which do not produce ammonia. The considered bacteria are Bacillus subtilis and Bacillus amyloliquefaciens. First, the optimized values of factors controlling CaCO production were determined. Then, wind tunnel tests were performed on sand dune samples treated with the optimized compositions, where wind erosion resistance, threshold detachment velocity, and sand bombardment resistance were measured. An optical microscope, scanning electron microscope (SEM), and X-ray diffraction analysis were employed to evaluate the CaCO polymorph. Calcium formate-based compositions performed much better than the acetate-based compositions in producing CaCO. Moreover, B. subtilis produced more CaCO than B. amyloliquefaciens. SEM micrographs clearly illustrated precipitation-induced active and inactive bounds and imprints of bacteria on CaCO. All compositions considerably reduced wind erosion.
沙尘暴对农业、人类健康、交通网络和基础设施造成的有害影响在世界许多国家构成严重威胁。因此，风蚀被认为是一个全球性挑战。一种环保的抑制风蚀的方法是利用微生物诱导碳酸钙沉淀（MICP）。然而，基于脲酶的 MICP 的副产物，如氨，在大量产生时是不利的。本研究介绍了两种用于非脲酶 MICP 的甲酸钙细菌组成物，并全面比较了它们与两种不产生氨的乙酸钙细菌组成物的性能。所考虑的细菌是枯草芽孢杆菌和解淀粉芽孢杆菌。首先，确定了控制 CaCO3 生产的因素的优化值。然后，在风洞试验中对用优化的组成物处理的沙丘样本进行了测试，测量了抗风蚀性、临界起动速度和沙粒冲击阻力。利用光学显微镜、扫描电子显微镜（SEM）和 X 射线衍射分析评估了 CaCO3 的多晶型。基于甲酸钙的组成物在产生 CaCO3 方面的性能明显优于基于乙酸钙的组成物。此外，枯草芽孢杆菌产生的 CaCO3 多于解淀粉芽孢杆菌。SEM 显微照片清楚地说明了沉淀诱导的细菌在 CaCO3 上的活性和非活性边界和压痕。所有的组成物都大大减少了风蚀。
