Supriya Hait¹, Gauri Chemburkar¹, Divya Murlidhar¹, Ulrica Almeida¹, Ruth Fernandez¹, Vivien Amonkar¹, Pampi Chakraborty^1,

‘Bio-cement’ is biologically produced salt largely calcium carbonate along with the cell mass of microorganisms. It is mainly generated by urease producing organisms. The present study focuses on the feasibility of using bio-cement to strengthen the marine soft clay in order to increase its water retention capacity. Eight urease producing organisms were initially isolated from sewage and four of them were selected based on their high urea (10%) tolerance. Growth parameters (pH and temperature) of the selected strains were also determined which ideally correlates with the bio-cement production. Further, one strain was selected for bio-cement production based on its maximum urease production studied on Christensen’s Urea plate by the well diffusion method. The selected strain was identified to be Klebsiella pneumoniae using 16S rDNA sequencing and biochemical tests which produced 0.46 g of bio-cement per liter of seawater after seven days of incubation at room temperature. The dried bio-cement was mixed with marine soft clay in a 1:1 ratio. The water retention capacity was checked intermittently for 72 hours and compared with untreated marine soft clay. It was evident from the results that water retention capacity of marine soft clay was strengthened using bio-cement. Thus, this combination can be utilized for construction of aquaculture ponds in sand, agriculture in marine soil and conservation of concrete structures, amongst several other ecofriendly applications.

bio-cement, Urease, Klebsiella pneumoniae, water retention capacity