title: Direct detection of formaldehyde in air by a novel NAD+- and glutathione-independent formaldehyde dehydrogenase-based biosensor.
abstract: An amperometric enzyme-based sensor-system for the direct detection of formaldehyde in air is under investigation. The biosensor is based on a native bacterial NAD(+)- and glutathione-independent formaldehyde dehydrogenase as biorecognition element. The enzyme was isolated from Hyphomicrobium zavarzinii strain ZV 580, grown on methylamine hydrochloride in a fed-batch process. The sensor depends on the enzymatic conversion of the analyte to formic acid. Released electrons are detected in an amperometric measurement at 0.2V vs. Ag/AgCl reference electrode by means of a redox-mediator. To optimize the sensing device, Ca(2+) and pyrroloquinoline quinone (PQQ) were added to the buffer solution as reconstitutional substances. At this stage, the sensor shows linear response in the tested ppm-range with a sensitivity of 0.39 microA/ppm. The signal is highly reproducible with respect to sensitivity and base line signal. Reproducibility of sensitivity is more than 90% within the same bacterial batch and even when enzyme of different bacterial batches is used.
authors.affiliation: Chair of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany. Sabine.Achmann@uni-bayreuth.de
authors.forename: S
authors.initials: S
authors.lastname: Achmann
authors.forename: M
authors.initials: M
authors.lastname: Hermann
authors.forename: F
authors.initials: F
authors.lastname: Hilbrig
authors.forename: V
authors.initials: V
authors.lastname: Jérôme
authors.forename: M
authors.initials: M
authors.lastname: Hämmerle
authors.forename: R
authors.initials: R
authors.lastname: Freitag
authors.forename: R
authors.initials: R
authors.lastname: Moos
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000445:Aldehyde Oxidoreductases / Q000737:chemistry*; D015374:Biosensing Techniques; D005557:Formaldehyde / Q000032:analysis*; D020582:Hyphomicrobium / Q000201:enzymology; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D000393:Air Pollutants; D005557:Formaldehyde; D000445:Aldehyde Oxidoreductases; C087006:formaldehyde dehydrogenase, glutathione-independent; D009247:NADH, NADPH Oxidoreductases