Indian Institute of Technology Madras Researchers have developed a structured model to help in the production of bio-cement, which is an alternative sustainable process for cementation. It has the potential to reduce the production of Carbon Dioxide (CO2) in the future.
Called ‘Microbially Induced Calcite Precipitation’ (MICP), this process is used to make bio-cement using bacteria (Ex: S. pasteurii). The Research was focused to gain better understanding of the MICP process with a long term aim to scale up manufacturing of Bio-Cement.
During the UN Climate Change Conference held at Glasgow last year, around 140 countries pledged to reduce carbon-di-oxide emission and achieve net-zero emissions. Cement manufacturing is among the largest CO2-producing industries. It is vital to develop alternative sustainable processes for manufacturing cement to reduce CO2 emissions and Bio-Cement can be a major step in this direction.
The IIT Madras Research team was led by Prof. G. K. Suraishkumar, Department of Biotechnology; Dr. Nirav Bhatt, Assistant Professor, Department of Biotechnology; and Ms. Subasree Sridhar, Research Scholar, IIT Madras. The findings of their research were published in the reputed peer-reviewed Biochemical Engineering Journal (https://doi.org/10.1016/j.bej.2021.108214).
The researchers studied the MICP process using the bacteria, S. pasteurii, proposed and developed a structured model for the overall ureolysis processes (uptake and breaking of urea using bacteria) to scale up the MICP process, which can be an alternative to manufacture cement.
Explaining the practical applications of this research, Prof. G.K. Suraishkumar, Faculty, Department of Biotechnology, IIT Madras, said, “The current applications are self-healing cement for sealing cracks in difficult-to-reach locations, consolidation of soil structures, removal of heavy metals and ‘radionuclides’ from drinking water, among others. A better understanding of the fundamental microbial processes such as overall ureolysis in the bio-cement formation could help us design and operate bioreactors for bio-cement production in the future to replace conventional cement for some applications”
Further, highlighting the impact of this research, Prof. G.K. Suraishkumar said, “In the short term, the better understanding would help us provide optimal conditions for effective self-healing cement applications, and soil consolidation, among other applications. In the long term, the better understanding would help produce conventional cement equivalent through a bio-route.”
Microbially Induced Calcite Precipitation (MICP) is the process by which calcium carbonate precipitates are formed by microorganisms, which are used to produce bio-cement. The developed structured model is useful for developing a unified model of ureolysis processes with calcite precipitation and MICP scale-up studies in the future.
Speaking on the current status of this research, Dr. Nirav Bhatt, Assistant Professor, Department of Biotechnology, IIT Madras, said, “MICP processes are currently modelled using unstructured models. Structured models of MICP provide better mechanistic insights into the bio-cementation process. Further, these models will be used in improving the process, rational process scale-up and optimization in the future.”
The Key Advantages of Bio-Cement over conventionally-manufactured cement include:
Bio-cement synthesis is more energy efficient as it requires temperatures in the range of 30 to 40 °C whereas conventional cement production requires above 900⁰C
Bio-cement is eco-friendly because it has negligible carbon dioxide emission, whereas conventional cement production is a significant contributor of global carbon dioxide emissions
Bio-cement production can potentially be more economical since industrial wastes such as Lactose Mother Liquor (LML) and Corn Steep Liquor (CSL) can also be used as raw materials for the bacteria
Bio-cement production is faster
Further, research on bio-cement has shown that it has comparable shear strength, durability and reduced water absorption capacity and permeability to the conventional cement.