Sorption of dissolved organic matter by freshwater bacterioplankton

Abstract

Here we describe the study of the sorption of high-molecular components of dissolved organic matter (DOM) of natural waters - humic acids - by eight bacterial strains isolated from freshwater. Isotherms of DOM sorption by cells are described by the Langmuir equation. Gram-positive bacteria adsorb more DOM than gram-negative bacteria, with high molecular weight DOM fractions binding in a relatively selective manner. A high positive correlation (r = 0.91) was found between the decrease in the molecular weight of DOM during the sorption of these compounds by cells and the maximum sorption value. The formation of a polysaccharide capsule increases the binding of DOM by the cells of Pseudomonas sp. to the level of gram-positive bacteria.