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Physicochemical characterization of Acidiphilium sp. biofilms

Abstract:

The biofilm formation of a strain of the extremophile bacterium Acidiphilium sp., capable of donating electrons directly to electrodes, was studied by different surface characterization techniques. We develop a method that allows the simultaneous study of bacterial biofilms by means of fluorescence microscopy and atomic force microscopy (AFM), in which transparent graphitic flakes deposited on a glass substrate are used as a support for the biofilm. The majority of the cells present on the surface were viable, and the growth of the biofilms over time showed a critical increase of the extracellular polymeric substances (EPS) as well as the formation of nanosized particles inside the biofilm. Also, the presence of Fe in Acidiphilium biofilms was determined by X-ray photoelectron spectroscopy (XPS), whereas surface-enhanced infrared absorption spectroscopy indicated the presence of redox-active proteins. Acidiphilium biofilms are grown on graphitic flakes and are characterized by different physicochemical techniques. Combined fluorescence-AFM microscopy is applied to study the biofilm formation over time and to detect nanosized particles that are, in turn, analyzed by X-ray photoelectron spectroscopy and attenuated total reflection surface-enhanced infrared absorption spectroscopy. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.