Optimization of an enzyme-based multi-parameter biosensor for monitoring biogas processes

An enzyme-based multi-parameter sensor chip for the simultaneous measurement of formate, D-and L-lactate is presented. Thereby, the combination of a diaphorase (DIA) from Clostridium kluyveri with different NAD+-dependent dehydrogenases enables the specific recognition of each compound. The amperometric detection is performed via monitoring of the oxidation current of enzymatically produced hexacyanoferrate(II) at +300 mV vs. Ag/AgCl. Chemical cross-linking with glutaraldehyde is used for enzyme immobilization. Thereby, the sensor signal is investigated at different concentrations of the cross-linker in the enzyme membrane. The obtained results indicate that by optimization of the immobilization matrix, the sensor performance can be improved. (C) 2015 The Authors. Published by Elsevier Ltd.