[Sorption of humic acids by bacteria].

Capacity for sorption of humic acid (HA) from water solutions was shown for 38 bacterial strains. Isotherms of HA sorption were determined for the cells of 10 strains. The bonding strength between the cells and HA (k) and the terminal adsorption (Q(max)) determined from the Langmuir equation for gram-positive and gram-negative bacteria were reliably different. Gram-positive bacteria sorbed greater amounts of HA than gram-negative ones (Q(max) = 23 ± 10 and 5.6 ± 1.2 mg/m2, respectively). The bonding strength between HA and the cells was higher in gram-negative bacteria than in gram-positive: k = 9 ± 5 and 3.3 ± 1.1 mL/mg, respectively.