ИСТИНА

Sorption of humic acids (HA) on bacteria were investigated mainly on Bacillus subtilis and Escherichia coli (Fein et al., 1999; Frost et al., 2003; Moura et al., 2007). It is studied the applied aspects of the fate metals in sediments and soils in the presence of microorganisms. It is assumed, that the sorption of HA on the cell surface should play a specific role in the interaction of living cells with other xenobiotics. 38 strains of bacteria different ecological groups adsorb HA from aqueous solutions We found, that the sorption parameters k and Qmax in Langmuir equation, which characterize the strength of binding HA with bacteria service and the maximum amount of adsorbed HA, respectively, were different for Gram-positive and Gram-negative bacteria. Gram-positive bacteria were sorbed HA more, but less strongly than the Gram-negative (Fig. 1). The difference in sorption of HA related with differences in the structure of the cell wall of Gram-positive and Gram-negative bacteria. Probably, the outer lipopolysaccharide layer of the cell wall of Gram-negative bacteria prevents to penetrate HA molecules in the underlying layer of peptidoglycan. Gram-positive bacteria haven’t the outer membrane, and HA can penetrate the peptidoglycan layer, which in order of magnitude in mass (and volume) of this layer in Gram-negative bacteria (Dobrovolskaya, 2002). Sorbed on bacteria HA protected the cells from the adverse effects of sodium dodecyl sulfate, and does not protect against sodium azide. HA binding bacterial cells can be used in non-waste technology treatment of dark-colored natural waters for water supply or for the protection of bacteria when introduced at adverse conditions This work was supported by grants RFBR № 11-04-00580-а, 12-04-01652-а, №12-04-31720 mol_а.