title: Strategies to develop malic acid biosensors based on malate quinone oxidoreductase (MQO).
abstract: An amperometric biosensor based on malate quinone oxidoreductase (MQO) was developed for monitoring of the malolactic fermentation of wines. Screen-printed electrodes coupled with appropriate mediators were used as transducers for this novel biosensor. MQO was immobilized by physical entrapment in a photo-cross-linkable poly(vinyl alcohol) polymer (PVA-SbQ) on the surface of the working electrode. Several electrochemical mediators were studied in order to lower the applied potential and minimise the matrix effects. Among them, 2,6-dichlorophenol indophenol (DPIP) and phenazine methosulfate (PMS) were chosen for further development. The working conditions (mediator concentration, applied potential and pH) were optimised for both DPIP and PMS. Detection limits for both types of biosensors were of 5 microM malic acid. Sensitivities obtained for the linear part of the calibration curve were 0.85 and 1.7 mA/M for the biosensors based on DPIP and PMS, respectively. Interferences due to non-specific oxidations were shown to be negligible when using PMS as mediator.
authors.affiliation: Université de Perpignan, BIOMEM, 52, Av. Paul Alduy, 66860 Perpignan Cedex, France.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Bucur
authors.forename: Elena
authors.initials: E
authors.lastname: Mallat
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Gurban
authors.forename: Yana
authors.initials: Y
authors.lastname: Gocheva
authors.forename: Carine
authors.initials: C
authors.lastname: Velasco
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marty
authors.forename: Thierry
authors.initials: T
authors.lastname: Noguer
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000379:methods*; D008293:Malates / Q000032:analysis* / Q000737:chemistry; D008832:Microchemistry / Q000295:instrumentation* / Q000379:methods; D010088:Oxidoreductases / Q000737:chemistry*; D014920:Wine / Q000032:analysis*
chemical_list: D008293:Malates; C030298:malic acid; D010088:Oxidoreductases; C471971:malate dehydrogenase, FAD-dependent