Effects of fullerene nanoparticles on Escherichia coli K12 respiratory activity in aqueous suspension and potential use for membrane biofouling control

Abstract

The attachment and respiratory activity of the model bacterium, Escherichia coli K12 on microfiltration (MF) membranes coated with the fullerene C 60 and the influence of colloidal aggregates of C 60 (nC 60) on this bacterium in a suspended culture environment were investigated in a low-salt medium. Deposition of C 60 on the surface of ceramic alumina membranes decreased the membrane surface zeta potential and increased the hydrophobicity of the membrane surface. These changes in membrane properties were correlated with a decrease in the number of bacteria observed on the membrane surface. Although a hydrophobic surface, with or without C 60, resulted in reduced bacterial attachment, our data indicate that C 60 impeded bacterial surface growth beyond that expected from hydrophobicity alone. Bacterial respiratory activity was also shown to be inhibited in suspended growth environments in the presence of the colloidal suspension of C 60. A reduction in respiratory activity was observed with increasing concentrations of nC 60 in the suspension. These results confirm that C 60 inhibits microbial respiratory activity and/or attachment and suggest that this material may be useful as an anti-fouling agent to prevent biofouling of membranes or other surfaces.