A preliminary investigation on isolation and identification of marine bacteria for biocementation in nearshore environments

Abstract

Microbial Induced Carbonate Precipitation (MICP) is a widely explored technique that involves utilizing bacterially produced carbonate biominerals for improving the engineering properties of soils. When this novel approach is used in cementing sandy soils in nearshore areas, it is necessary to identify suitable bacterial strains which are resistant to high saline dynamic marine environments. Thus, current study was carried out to isolate and identify ureolytic bacteria from Sri Lankan beach sand and to check their suitability for use in MICP. To accomplish this, bacterial strains were isolated from beach sand samples and urease activity was determined. MICP capability was evaluated by cultivating the species on agar plates containing CaCh and urea. Based on these results, four isolates having high feasibility to induce bacterially precipitated calcium carbonates were selected and identified by 16S rDNA gene sequencing. Two strains were identified as belonging to Halomonas sp. and other two to Sulfitobacter sp. and OceanobaciUus sp. genera. Further analysis was done to determine the bacterial cell growth of isolates at different temperatures and concluded that all four isolates have a more stable growth at temperature close to 30°C. Isolates were evaluated for their biosafety and found to be non pathogenic. However, detailed analysis on biomineralization by the selected isolates and their biological behaviour is recommended prior to any large scale applications.