Fig 3.

ICP-OES quantification of mercury removal by dead bacterial biomass. (A) Quantification of the mercury contents (expressed as percentages of the initial metal content) in bacterial pellets (gray areas of bars) and supernatants (open areas of bars) after incubation of dead bacterial biomass in the presence of 2 mM HgCl₂. (B) Mass of mercury (expressed as milligrams per gram [dry weight] of bacterial biomass) after incubation of dead bacterial biomass in the presence of 1 mM (shaded bars) or 2 mM (filled bars) HgCl₂. Error bars represent standard deviations for triplicate experiments. Although the Kruskal-Wallis test performed on the whole set of strains revealed a nonhomogeneous distribution of the mass (mg/g) and content (percentage) of Hg within the pellets for all strains (P = 0.003), no significant difference between strains was found by using the pairwise Wilcoxon-Mann-Whitney test.