Influence of X-ray µ-Computed Tomography on the microbial activity of a mixed thermophilic and mesophilic bioleaching culture colonising a mineral surface

This study therefore evaluates the compatibility bioleaching microorganisms with X-ray energy exposure. The X-ray effect on a mixed thermophilic culture suspended in solution was assessed using imaging conditions of 35-150 kV, 200-280 µA and 1-2 hours. Microorganisms were unaffected between 35-90 kV and 200-280 µA while there was some detrimental effect at 120 and 150 kV. The X-ray influence on a mixed mesophilic culture colonising a mineral surface was investigated at 90 kV and 225 µA for a 1 hour exposure time. The system was monitored before and after exposure through measurement of: redox potential of the effluent solution, microbial cell concentration, heat output from the colonised surface using isothermal microcalorimetry (IMC), and cell attachment on the ore surface using scanning electron microscopy (SEM). The redox and cell concentration measurements showed insignificant differences between exposed and unexposed samples. Equivalent heat generation and good colonization of the mineral surface was demonstrated, confirming continued microbial activity post exposure, hence recommending its use in support of bioleaching studies.
Source: Biochemical Engineering Journal - Category: Biochemistry Source Type: research