An Amperometric Biosensor for the Determination of Lactic Acid During Malolactic Fermentation

Abstract

A lactate oxidase amperometric biosensor was developed and optimized for the malolactic fermentation monitoring during winemaking process. Lactate oxidase enzyme was immobilized on prussian blue modified screen-printed carbon electrode in order to reduce the electrochemical interferences due to the high content of electroactive compounds abundant in wine and must, such as polyphenols and ascorbic acid. The lactate oxidase biosensor developed showed high sensitivity (852 µA M-1) and a detection limit for lactic acid of 0.005 mM (0.45 mg L-1) The operational stability and the life time of the biosensors were also evaluated equal to 8 h and 30 days respectively. Finally the biosensor in flow injection system was used for lactic acid analysis during malolactic fermentation of a red wine and the results were compared with those registered by ion chromatography with good agreement with two sets of data.