Our suggestion for the bio-uptake mechanism of the three studied bacteria is an active uptake mechanism in which the heavy metal is only being absorbed at the cell surface (Malik, 2004). The interaction between the metals and the microbes is recovery, detoxification or removal of the metals (Gadd, 2004). This suggestion was based on the fact that MK-0752 the device used (CVAAS) measures the total concentration of mercury (organic, inorganic, and elemental) so if the mechanism used by a bacterial strain is by changing the form of mercury from elemental to organic, the difference will not be detected by the device (Landi and Fagioli, 1994, Shah et al., 2010 and Voegborlo and Adimado, 2010). Therefore the reported bio-uptake capacity of our bacterial strains (C. muytjensii, E. helveticus, and C. amalonaticus) is mainly explained by their abilities to bio-uptake mercury by storing and absorbing it in their cytoplasm hence less mercury levels were reported after the removal of bacterial cells from the filtrate used for measurement. Our suggestion coincides with the study of Sinha and Khare (2012) as they reported similar mechanism of bio-uptake for Enterobacter sp.
↧