to establish the mass balance. Surprisingly, while Cr(VI) concentration
decreased as shown in Fig. 2, total Cr remained at culture
supernatants, only traces were found in cell fractions (Fig. 5).
The Cr(III) concentrations in the supernatants (shown in Fig. 5)
are all very near the initial value of 0.05mM,showing a quantitative
reduction together with the fact of this ion remaining in solution in
spite of the pH reached at the end of the experiments (between
7 and 8) that seems to be adequate for the precipitation of the
hydroxide. The possible reactions between the extremely stable