A new bacterial concentration method for large-scale applications of biomineralization

Abstract

Bacterial suspension is an essential component of microbially induced carbonate precipitation (MICP)-based biocement and a large-scale production is required for field applications. In this study, a new bacterial concentration method is proposed to enable high concentration bacterial suspension to be produced to facilitate field work. By adding low concentration calcium to bacterial suspension, flocs are formed and bacterial cells are adsorbed on the flocs to achieve bacterial concentration. Compared to the traditional bacterial concentration method using centrifugation and freezing-drying method, the proposed method can concentrate a large volume of bacterial suspension without using special equipment. The feasibility of this method is verified by bacterial concentration tests, solution tests and sand column treatment tests. The results of both the solution test and the sand column treatment test show that the bacterial suspension concentrated by the proposed method can be effectively used for soil biocementation. There is a threshold calcium concentration that allows a complete bacterial concentration for the proposed method, and this threshold calcium concentration tends to increase linearly with the optical density of the cell suspension at a wavelength of 600 nm (OD600).