Effect of temperature on the sensitivity of cascaded lactose biosensors

The sensitivity and application options of cascaded lactose biosensors along with the catalytic activity of three enzymes (beta-galactosidase, glucose oxidase, and galactose oxidase) used for bio-recognition in these biosensors were studied at different temperatures ranging from 4 to 38.6 degrees C, the usual temperature span in the milk processing. Although at 4 degrees C, which is the common temperature of raw milk storage, the apparent activity of these enzymes was quite low and the resulting biosensor sensitivity decreased nearly 100 times in comparison with its sensitivity at 38.6 degrees C, it was possible to carry out lactose measurements with a biosensor comprising beta-galactosidase and glucose oxidase within 10 min.