Difference in mercuric ion removal by resting and growing cells of two mercury-resistant yeast strains, identified as Yarrowia spp. (strains Idd1 and Idd2), were studied. Resting cells of strain Idd2 exhibited high maximum Hg2+ removal capacity (59 mg mercury per g dry cell weight [gdw−1]) by adsorption than those of resting cells of strain Idd1 (32 mg gdw−1). The resting cells of strain Idd2 exhibited a higher Hg2+ desorption capacity using CaCl2 (68 %) and EDTA (48 %) than strain Idd1, depicting weaker binding of Hg2+ onto strain Idd2 unlike strain Idd1. The actively growing yeast cells showed opposite Hg removal characteristics to those of the resting cells. Strain Idd1 adsorbed less Hg2+ from culture medium supplemented with Hg2+ than strain Idd2. However, the growing strain Idd1 reduced and vaporized 27 % of supplemented Hg2+ as metallic mercury (Hg0), while the growing strains Idd2 vaporized 15 % of the supplemented Hg2+. These two yeast strains are potential biotechnological tools for the eventual bioremediation of polluted aquatic systems.
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