Recombinant Microdochium nivale carbohydrate oxidase and its application in an amperometric glucose sensor

Biosensors containing recombinant carbohydrate oxidase from Microdochium ni vale (rMnO) were developed by means of either chemically modified carbon pa ste or graphite electrode. 1-(N,N-dimethylamine)-4-(4-morpholine)benzene (A MB) and 1,1'-dimethylferrocene (DMFc) have been used as mediators. The bios ensors showed a linear calibration graph up to 18 mM of glucose when operat ed at 0.04-0.36 V versus a saturated calomel electrode. Almost no change wa s detected in the sensitivity of the biosensors at pH 7.2-8.1. The biosenso rs responded to other aldoses in the D-configuration, however, maximal sens itivity of the biosensor was towards D-glucose. The biosensor did not respo nse to polyhydroxylic compounds such as D-mannitol, D-sorbitol and inositol . The advantages of the biosensors based on rMnO in comparison to Aspergill us niger glucose oxidase is a wider linear range, low sensitivity to oxygen and (in some cases) broad specificity. (C) 2001 Elsevier Science B.V. All rights reserved.