Study of the interaction of sulphate-reducing bacteria exopolymers with iron using X-ray photoelectron spectroscopy and time-of-flight secondary ionisation mass spectrometry

Abstract

Time-of-flight secondary ionisation mass spectrometry and X-ray photoelectron spectroscopy were employed to determine the interaction of crude extracellular polymeric substances recovered from static batch cultures of two isolates of marine sulphate-reducing bacteria of the genus Desulfovibrio, grown in the presence of and without mild steel surfaces, with Fe ions released from steel. The results demonstrated that exopolymers synthesised by different strains of sulphate-reducers varied in their ability to bind iron originating from steel. Based on the X-ray photoelectron spectroscopy analysis it is proposed that Fe released from steel was associated with bacterial exopolymers such as Fe(III) ion. The application of surface science techniques to study exopolymer/metal interaction allowed quantitative evaluation of Fe binding using small sample size.