On-Line Monitoring System of Lactic Acid Fermentation by Using Integrated Enzyme Sensors

Abstract

An on-line monitoring system for lactic acid fermentation is developed by using integrated micro enzyme sensors, a flow injection analysis system, and a micro dialysis system. The calibration curves ofmicro glucose, lactose and lactate sensors show good linearity in the concentration range below 70 mM By combination with the micro dialysis system, the enzyme sensors can measure the whole concentration range of lactic acid fermentation, and interference by the medium can not be observed.The on-line sensor system is then applied to lactic acid fermentation of Lactobacillus delbrueckii. The sensor systemcan monitor the glucose and lactate concentrations simultaneously during 24-h fermentation, and the measurements show good agreement with those of the conventional colorimetric method.
The sensor system can also be applied to on-line monitoring of lactose and lactate during Lactobacillus lactis fermentation.