INTERACTION OF MERCURIC IONS WITH THE BACTERIAL-GROWTH MEDIUM AND ITS EFFECTS ON ENZYMATIC REDUCTION OF MERCURY

The interaction of Hg2+ with components of Luria-Bertani broth (LB), used to grow the mercury-resistant strain Pseudomonas aeruginosa PU21 (Rip64), was studied using cold vapor atomic absorption spectrometry and liquid scintillation counting. The time course analysis of free Hg2+ and total Hg in LB solutions showed that 30-40 % of Hg2+ formed complexes with tryptone and yeast extract within 140 h. Media containing free or complexed Hg2+ were treated with cell-free mercuric reductase as well as with growing cells to investigate the effect of the Hg2+-LB interaction on mercury reduction. In both assays, it was found that the complexed Hg2+ Could not be reduced by mercuric reductase or P. aeruginosa PU21 (Rip64).