Amperometric bi-enzyme based biosensor for the detection of lactose--characterization and application

Area of Science:

• Biotechnology
• Enzyme Engineering
• Biosensor Development

Background:

• Lactose determination is crucial in food and clinical diagnostics.
• Existing methods for lactose analysis can be time-consuming or require specialized equipment.
• Development of rapid and specific biosensors is an ongoing area of research.

Purpose of the Study:

• To develop and characterize a novel enzyme probe for the specific determination of lactose.
• To compare beta-galactosidases from different sources for optimal sensor performance.
• To validate the sensor's accuracy and stability in various sample matrices.

Main Methods:

• Development of a bi-enzyme probe utilizing glucose oxidase and beta-galactosidase.
• Characterization of the sensor with beta-galactosidase from Curvularia inaequalis, assessing optimal pH, enzyme loading, activity, and stability.
• Linear response range determination for lactose concentration.
• Validation against enzymatic photometric and infrared detection methods.

Main Results:

• The developed enzyme probe exhibits a linear response to lactose concentration from 0.02 to 3.00 mmol dm-3.
• The sensor incorporating beta-galactosidase from Curvularia inaequalis demonstrated good functional stability.
• Excellent correlation was observed between the enzyme probe and established detection methods (enzymatic photometric and infrared).
• Low serial imprecision (approx. 2%) was achieved at a high measuring frequency (100 h-1).

Conclusions:

• The glucose oxidase-beta-galactosidase enzyme probe provides a specific and sensitive method for lactose determination.
• The biosensor demonstrates robust performance and stability, suitable for practical applications.
• This enzyme probe offers a reliable alternative for analyzing lactose in diverse samples like milk, urine, and foodstuffs.