A putative polysaccharide adhesin which mediates non‐specific attachment ofHyphomonasMHS‐3 (MHS‐3) to hydrophilic substrata has been isolated and partially characterized. A polysaccharide‐enriched portion of the extracellular polymeric substance (EPSP) from MHS‐3 was separated into four fractions using high performance size exclusion chromatography (HPSEC). Comparison of chromatograms of EPSPfrom MHS‐3 and a reduced adhesion strain (MHS‐3 rad) suggested that one EPSPfraction, which consisted of carbohydrate, served as an adhesin. Adsorption of this fraction to germanium (Ge) was investigated using attenuated total reflection Fourier transform infrared (ATR/FT‐IR) spectrometry. Binding curves indicated that the isolated fraction had a relatively high affinity for Ge when ranked against an adhesive protein fromMytilis edulis, mussel adhesive protein (MAP) and an acidic polysaccharide (alginate fromMacrocystis pyrifera). Spectral features were used to identify the fraction as a polysaccharide previously reported to adsorb preferentially out of the EPSPmixture. Conditioning the Ge substratum with either bovine serum albumin (BSA) or MAP decreased the adsorption of the adhesive polysaccharide significantly. Conditioning Ge with these proteins also decreased adhesion of whole cells.