A STUDY OF THE RELATIONSHIP BETWEEN THE SURFACE CHARGE AND THE ADSORPTION OF ACID DYES BY BACTERIAL CELLS'

Studies of the adsorption of acid dyes of the fluorane series have shown that more of the dye is adsorbed by bacteria under acid conditions than under basic or neutral conditions (Harris, 1949). The amount of dye adsorbed was also found to be related to the ionization of the dye molecule. Since both the bacterial cell and the dye anion carry negative charges, these findings suggest that as the H+ of the medium is increased the charge on the cell becomes less, thus allowing greater combination between the cell and the dye anion. It is known that a number of environmental factors influence the electrical charge of the bacterial cell (Abramson, 1934). This investigation was undertaken to study the adsorp-tion of acid dyes in relation to the charge of the bacterial cell as determined by electrophoretic measurements. EXPERIMENTAL RESULTS The procedures used in growing large numbers of bacterial cells and the measurement of dye adsorption were the same as described previously (Harris, 1949). Electrophoretic measurements were made following the general method