title: Fibre-optic bacterial biosensors and their application for the analysis of bioavailable Hg and As in soils and sediments from Aznalcollar mining area in Spain.
abstract: Fibre-optic biosensors for Hg and As were developed by attaching alginate-immobilised recombinant luminescent Hg- and As-sensor bacteria onto optical fibres. The optimised biosensors (consisting of seven layers of fibre-attached bacteria pre-grown till mid-logarithmic growth phase) enabled quantification of environmentally relevant concentrations of the target analytes: 2.6 microg l-1 of Hg(II) and 141 microg l-1 of As(V) or 18 microg l-1 of As(III). The highest viability and sensitivity for target analyte was obtained when fibre tips were stored in CaCl2 solution at -80 degrees C. Applicability of the fibre-optic biosensors in parallel to the respective non-immobilised sensors was assessed on 10 natural soil and sediment samples from Aznalcollar mining area (Spain). On the average 0.2% of the total Hg and 0.87% of the total As proved bioavailable to fibre-attached bacteria. Interestingly, about 20-fold more Hg and 4-fold more As was available to non-immobilised sensor bacteria indicating the importance of direct cell contact (possible only for non-immobilised cells) for enhanced bioavailability of these metals in solid samples.
authors.affiliation: National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia. angela@kbfi.ee
authors.forename: Angela
authors.initials: A
authors.lastname: Ivask
authors.forename: Tal
authors.initials: T
authors.lastname: Green
authors.forename: Boris
authors.initials: B
authors.lastname: Polyak
authors.forename: Amit
authors.initials: A
authors.lastname: Mor
authors.forename: Anne
authors.initials: A
authors.lastname: Kahru
authors.forename: Marko
authors.initials: M
authors.lastname: Virta
authors.forename: Robert
authors.initials: R
authors.lastname: Marks
mesh_terms: D001151:Arsenic / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004926:Escherichia coli / Q000235:genetics; D005336:Fiber Optic Technology; D019015:Geologic Sediments / Q000032:analysis*; D008164:Luminescent Proteins / Q000235:genetics; D008628:Mercury / Q000032:analysis*; D008906:Mining; D012989:Soil Pollutants; D013030:Spain
chemical_list: D008164:Luminescent Proteins; D012989:Soil Pollutants; D008628:Mercury; D001151:Arsenic