Adhesion of a Mycobacterium sp. to cellulose diacetate membranes used in reverse osmosis

The kinetics of adhesion of a Mycobacterium sp. to cellulose diacetate reverse-osmosis membranes is described. This Mycobacterium sp. (strain BT2-4) was previously implicated in the initial stages of reverse-osmosis membrane biofouling at a wastewater reclamation facility. Adhesion of BT2-4 cells to the cellulose diacetate membrane surfaces occurred within 1 to 2 h at 30 degrees C and exhibited saturation-type kinetics which conformed closely to the Langmuir adsorption isotherm (Pearson r correlation coefficient = 0.977), a mathematical expression describing the partitioning of substances between a solution and solid-liquid interface. This suggests that the cellulose diacetate membrane surfaces may possess a finite number of available binding sites to which the mycobacteria can adhere. Treatment of the attached mycobacteria with different enzymes suggested that cell surface polypeptides, alpha-1, 4- or alpha-1,6-linked glucan polymers, and carboxyl ester bond-containing substances (possibly peptidoglycolipids) may be involved in mycobacterial adhesion. The possible implication of these findings for reverse-osmosis membrane biofouling are discussed.