Experimental Investigation of Bio-concrete

Abstract

The present study focussed on the screening and identification of calcite precipitating bacteria with a goal to check the suitability of the potential strain in concrete to advance its strength and durability. For this, a total of sixteen samples comprising eight alluvial soil (alkaline in nature and rich in Iron oxide and lime) samples and eight sewage samples were collected from the different locations of district Solan (H.P). For isolation, enrichment culture technique was used to enrich calcite precipitating strains in Urea broth. After enrichment, fourteen distinct bacterial colonies were obtained on Urea agar. All the strains were gram-positive rods or coccus in shape. All the fourteen bacterial cultures were screened for qualitative urease assay and quantitative electric conductivity test. The calcite precipitation was also determined by taking dry weight of the precipitates in urea broth supplemented with calcium chloride. Based on the screening results, five isolates were selected possessing high calcite formation along with higher urease activities. All the results were compared with standard strain of Bacillus megaterium MTCC 1684, already reported for high calcite formation. The compressive strength and quantification of crack healing observed and the positive results shown by two bacterial species. The DNA extraction of these species done and the sequencing was performed.