Investigate the potential of applying microbially induced calcium carbonate precipitation (MICP) for copper removal

Abstract

My thesis project aimed to investigate the potential of ureolytic bacteria, which isolated from the soil near the Rock lakes in the National University area. These lakes were formed due to the process of quarrying by the mining company in 1993. New strains are expected to be more effective in removing copper by precipitation. In addition, evaluation of correspondence between the copper precipitation with the calcium precipitation, and EPS extraction of the ureolytic bacteria were performed to check whether these two factors can affect the ability to precipitate copper. Five strains of bacteria, which were O1, O2, N3, N4, N5, were isolated based on the presence of urease which was split from ureolytic bacteria on the Urea Agar plate, which changed color from orange to pink due to the increase of pH. Then, the amount of copper precipitate were estimated with the highest percentage of copper precipitate was 41% and the lowest was 30%. In addition, the amount of calcium precipitate and the Extracellular Polymeric Substance (EPS) extraction were performed in order to check the correlation with the total amount of copper precipitate. As the results, it seemed to be no correlation with the calcium precipitation process, but have correlation with the total amount of EPS extraction. To recapitulate briefly, all of ureolytic bacteria strains have the ability to remove copper by precipitation. Keywords: Ureolytic bacteria Copper precipitation Copper removal Calcium Precipitation EPS extraction