Review of the use of microorganisms in geotechnical engineering applications

Abstract

Until recently, engineers either ignored or neglected the role of microorganisms in geotechnical engineering. The microbially induced calcite precipitation (MICP) research technique is an innovative and relatively green technology which consists in a biological process through which microorganisms react with minerals (calcium source and cementation reagent) to produce calcite (CaCO 3 ) as a byproduct that modifies and improves the engineering properties of soil. Laboratory and field results obtained from various studies are promising and viable, suggesting potential for various engineering applications. This research technique has also been considered to be useful in many engineering applications such as improvement of construction materials, cementation of porous media, improvement in strength and stiffness of engineering soils, hydraulic control of engineering facilities (waste containment), liquefaction, and erosion mitigation. In this review, the various methods of production of calcium carbonates (calcite), the role played by bacteria, various state-of-the-art procedures that have evolved in this research area, as well as ongoing studies are reported. Furthermore, the use of the MICP technique in remediation of contaminants and other environmental concerns is also presented. The advantages and challenges (in form of undesired byproducts) of this research technique are highlighted herein.

The diversity of molecular mechanisms of carbonate biomineralization by bacteria

“…Finally, bacterial carbonate biomineralization can be used for stabilizing soils and sediments [32], and restoring weathered limestone and cement monuments [30,33]. More details on the use of microbially precipitated CaCO 3 as biomaterials can be found in several recent review papers [34][35][36][37][38].…”

State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications

“…The effectiveness of MICP in cementing soil depends on the types of bacteria used, the methods of growing these to the required concentration, the pH and temperature during urea hydrolysis, the concentration and flow rate of cementation solution (e.g., calcium concentration and input flow rate), the soil properties (e.g., the availability of nucleation sites, degree of saturation, soil gradation, particle size, pore throat size) and so forth [2][3][4][5][6]. It is noteworthy to report that there are a number of review articles published in the past focusing on a particular aspect of MICP, e.g., optimizing protocols [7], mitigating liquefaction [8,9], stabilization [7,[9][10][11], construction [12] and other aspects [13][14][15][16][17][18][19][20]. A comprehensive review of the current state of knowledge on overall MICP processes, application and sustainability has not yet been undertaken.…”

“…Figure13. Experimental and modelling of DSS results for untreated and MICP-treated soil: (a) stressstrain responses and (b) stress paths (data adapted from[136]).…”

Enhancing the Strength of Sandy Soil Through Enzyme-Induced Calcite Precipitation

“…Over the last decade, substantial research has been carried out on the use of biomediated and bio-inspired soil improvement techniques to improve the geotechnical properties of mostly granular soils [4][5][6]. These biogeotechnical techniques are promising, environmentally friendly and sustainable soil improvement techniques [7,8]. Biogeotechnical processes occur through several pathways, such as urea hydrolysis, denitrification, sulphate reduction, iron reduction, and ammonification; however, urea hydrolysis is the most widely adopted method by researchers [5,7].…”