Poster Presentation Australian Microbial Ecology 2019

Microbial community dynamics under concrete environments in search for novel alkalophiles for potential application of Biocement (#165)

Sakshi Tiwari 1 , Pelin Polat 1 , Abhijit Mukherjee 1 , Navdeep Dhami 1
  1. Curtin University, Perth, WESTERN AUSTRALIA, Australia

Microbially Induced Carbonate Precipitation (MICP) has recently emerged as a potential technology for generation of low energy, self-healing and sustainable cement with applications in remediation and restoration of building materials. This bio-based process has been developed from the principle of biomineralization wherein microbial metabolic activities lead to cementation of natural structures as corals, beach rocks, caves etc at ambient temperature conditions making the whole process highly energy efficient. This bacterially induced mineralization has been mimicked in laboratory conditions for creation of Biocement which offers the benefits of formation at ambient temperature conditions, is highly sustainable, durable, self-healing and recyclable. Most of the applications of Biocement in engineering sector till date have utilised ureolytic, alkalophilic strain Bacillus pasteurii which offers optimal biocementation under moderately alkaline environments of pH 9 and low salinity but actual concrete environments are much harsh with pH upto 13 and exposure to marine conditions with salinity upto 5%. Under actual harsh concrete environments, the viability and metabolic activity of standard lab strains has been found to decline tremendously which is quite challenging for successful applications. In the current study we have made an attempt to understand microbial dynamics under highly alkaline concrete environments and then isolate extremophilic strains with higher viability, metabolic activity and Biocement formation in order to improve the applications of this sustainable technology in actual concrete environments. For this study, we have selected three alkalophilic sites including cement, calcareous soils and microbialites to enrich ureolytic alkalophilic strains under concrete simulated environments reaching upto pH 13 and salinity upto 5% and low nutrient conditions. Significant changes in the community dynamics were recorded from naturally alkaline to concrete simulated environmental conditions. Few extremophilic (ureolytic, alkalophilic) strains were successfully isolated with potential to produce Biocement under actual concrete environments. Further studies are being carried out to understand the molecular mechanisms involved in survival and metabolisms of these strains to endure such extreme environments in order to improve our knowledge along with efficacy of self-healing Biocement for Civil and Geotechnical sector.