Nanoparticle Accumulation in Microbial Induced Carbonate Precipitation: The Crucial Role of Extracellular Polymeric Substance

Abstract

Microbes and their secreted extracellular polymeric substance (EPS) could regulate the mineral phases, morphologies and structure of the microbial induced carbonate precipitates (MICPs). Here, two groups of mineralization experiments were carried out respectively to investigate the mechanism of the microbial induced carbonate precipitation (MICP) using Arthrobacter sp. MF-2 strain and its EPS. X-ray diffraction (XRD) were used to characterize the mineral species and scanning electron microscopy (SEM) was used to investigate the morphologies of the precipitates. Besides, focused ion beam (FIB) was used to prepare calcified bacterial slice for transmission electron microscopy (TEM) analysis. Meanwhile, the temporal change of bacterial density, pH value, conductivity, weight of precipitates, Ca2+ concentration and EPS content were also recorded. The results of this paper showed EPS could serve as the stabilizer of unstable phases and the scaffold for the accumulation of nanoparticles.