A Comparative Study of Various Parameters Influencing Biocalcification via Ureolysis Mediated by Enzyme and Microbe: A Comprehensive Review

The biocalcification process in soil via urea hydrolysis is mediated by bacterial urease enzyme (microbially induced carbonate precipitation, MICP) or free urease (enzyme induced carbonate precipitation, EICP). MICP and EICP are nascent and potentially sustainable soil improvement techniques that can possibly be more environment friendly than conventional chemical and mechanical methods. It is felt that the guidelines for employing either of these techniques for a target application are not fully explored in the literature. Keeping this in view, a comprehensive review of various parameters influencing the carbonate precipitation reaction and improvement in strength via MICP and EICP has been presented. Further, an attempt has been made to enable the reader to choose between MICP and EICP for the target application based on biological, environmental, chemical, and geotechnical constraints that need to be adhered to in their study. It is felt that such a review would be handy in selecting the process and thereby improve the viability of the mechanism to head to large-scale field applications.