Medium-induced inhibition of microbial adsorption to nickel and activated charcoal

Equilibrium adsorption studies on Escherichia coli and Saccharomyces sp. revealed the capacity and affinity of these organisms for the surfaces of powdered charcoal and nickel. In simple salt solutions both organisms readily adsorbed to each solid with an affinity and maximum loading capacity individual to each cell-solid combination. In the presence of common growth media (lab-lemco, nutrient broth, peptone, and yeast extract, individually at a concentration of 1.3%), each medium substantially inhibited adsorption. Each medium contained a proteinaceous constituent as determined by ultraviolet (UV) analysis. The degree of inhibition was relative to medium concentration present during assay. Cell wall extracts from whole-yeast cells also effectively inhibited adsorption. Cells adsorbed in the presence of sodium chloride solutions were susceptible to subsequent desorption by nutrient broth.