Pratika Kakad and Prafulla Shede
Abstract
Concrete is one of the most widely used construction materials in various infrastructures. However, despite of several advantages, it has a high tendency to form cracks due to climatic effects and parameters like temperature fluctuations, exposure to corrosive and toxic chemicals, harmful gases, natural disasters, etc. These factors reduce the longevity of concrete which adds up to the cost of the maintenance and repair. Existing treatments have various limitations like weak resistance to weather, moisture sensitivity, heat and low sustainability. Hence, there is a need for alternative and sustainable treatment technologies. One such technology is bioconcrete formation by the process of Microbially Induced Calcium Carbonate Precipitation (MICP). In nature, MICP occurs through different processes like urea hydrolysis, photosynthesis, denitrification, etc. Bio concrete is a combination of concrete and bacteria possessing the ability to precipitate calcium carbonate (CaCO3) that aids in sealing the cracks that appear in it. This self-healing property of bio concrete can be a potentially sustainable and economic technology. This study was aimed to enrich, isolate and screen bacteria capable of precipitating CaCO3 and their use in production of bio concrete. Total 11 samples predominantly containing speleothems and related materials were collected from different locations in Satara and Nashik districts of Maharashtra, India. The samples were further processed independently in B4 and Calcium Carbonate Precipitation (CCP) media for enrichment. A total of 94 isolates were obtained from the enriched samples. Subsequent screening and characterization of these isolates revealed that Paenibacillus fonticola and Sporosarcina luteola can substantially precipitate calcium carbonate. The Fourier Transform Infrared (FTIR) spectra, Scanning Electron Microscopy (SEM) and Energy Dispersive Xray (EDX) microanalysis of the CaCO3 precipitates formed by these bacteria renders both Paenibacillus fonticola and Sporosarcina luteola the potential candidature for bioconcrete formation.