Whole-cell electric sensor for determination of sodium dodecyl sulfate

Linear alkyl sulfates are a major class of surfactants that have large-scale industrial application and thus wide environmental release. These organic pollutants threaten aquatic environments and other environmental compartments. We show the promise of the use of a whole-cell electric sensor in the analysis of low or residual concentrations of sodium dodecyl sulfate (SDS) in aqueous solutions. On the basis of bioinformatic analysis and alkylsulfatase activity determinations, we chose the gram-negative bacterium Herbaspirillum lusitanum, strain P6-12, as the sensing element. Strain P6-12 could utilize 0.01-400 mg/L of SDS as a growth substrate. The electric polarizability of cell suspensions changed at all frequencies used (50-3000 kHz). The determination limit of 0.01 mg/L is much lower than the official requirements for the content of SDS in potable and process water (0.5 and 1.0 mg/L, respectively), and the analysis takes about 1-5 min. The promise of H. lusitanum P6-12 for use in the remediation of SDS-polluted soils is discussed.