Study of the interactions between S. pasteurii and indigenous bacteria and the effect of these interactions on the MICP
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ORIGINAL PAPER
Study of the interactions between S. pasteurii and indigenous bacteria and the effect of these interactions on the MICP Peng Liu 1,2
&
Guang-hui Shao 1,2 & Rong-pin Huang 1,2
Received: 3 December 2018 / Accepted: 9 September 2019 # Saudi Society for Geosciences 2019
Abstract A new soil improvement method, called microbial-induced calcite precipitation (MICP), has recently emerged, which is based on microbial mineralisation by injecting bacteria solution and nutrient into soil for the purpose of modifying physico-mechanical properties. Since the MICP process in natural soils is likely to be impacted by the interactions between Sporosarcina pasteurii and indigenous bacteria, we herein examine these interactions and their effects on MICP. The soil extract was used as a source of natural microorganisms, and a control treatment was inoculated in an artificial solution, based on the soil extract with no microorganisms. The following parameters were monitored in the whole process of the experiments: optical density (OD), pH, dissolved Ca2+ and dissolved inorganic carbon (DIC). The results show that dissolved Ca2+ precipitate as CaCO3 more quickly in the control than in natural soil extract. S. pasteurii exhibits a significantly higher growth rate in the artificial soil extract than in the natural solution, which results in a higher density of bacterial cells. We suggest that the presence of the indigenous bacteria decelerates the MICP process by competing with S. pasteurii for nutrients. Keywords Soil improvement . Microbial-induced calcite precipitation (MICP) . Bio-cementation . Sediment
Introduction A new soil improvement method, called microbial-induced calcite precipitation (MICP), has recently emerged, which is based on microbial mineralisation by injecting bacteria solution and nutrient into soil for the purpose of modifying physicomechanical properties (Ivanov and Chu 2008; Dejong et al. 2011). A majority of microorganisms in soil can induce CaCO3 precipitation through a lot of biochemical reactions: urea hydrolysis, denitrification, dissimilatory Fe(III) reduction, and sulphate reduction (Qiang et al. 2018a; Yongxing et al. 2019). Furthermore, urea hydrolysis of microorganisms is the most commonly used method for biomineralisation, for its simple,
Responsible Editor: Zeynal Abiddin Erguler * Peng Liu [email protected] 1
School of Civil Engineering, Nanjing Forestry University, Nanjing, People’s Republic of China
2
Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, Nanjing, People’s Republic of China
low-cost, and controlled reactions, and high yield of CO32− ions in a short time. Ureolysis-driven MICP mainly uses Sporosarcina pasteurii, which is an alkaliphilic bacteria that has a strong environmental adaptability and high urease activity. A large amount of high-activity urease is produced in their metabolic activities, which catalyses the hydrolysis of urea to yield NH4+ and CO32−. The reaction is described as follo
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