Multi-enzyme electrodes for the determination of starch by flow injection

Area of Science:

• Biotechnology
• Biosensors
• Analytical Chemistry

Background:

• Starch determination in flowing streams requires sensitive and stable analytical methods.
• Enzyme-based biosensors offer high specificity for carbohydrate analysis.

Purpose of the Study:

• To develop a tri-enzyme electrode for amperometric determination of starch.
• To optimize enzyme ratios for enhanced starch sensing capabilities.
• To evaluate the performance and operational properties of the developed biosensor.

Main Methods:

• Fabrication of nylon-based starch-sensing membranes with varying ratios of amyloglucosidase (AMG), mutarotase (MUT), and glucose oxidase (GO) over a platinum electrode.
• Amperometric monitoring of hydrogen peroxide at +600 mV versus a silver-silver chloride reference electrode.
• Pre-incubation of starch samples with soluble alpha-amylase (alpha-AMY) prior to analysis with the tri-enzyme electrode.

Main Results:

• The optimal electrode (type A) utilized an enzyme cocktail of AMG--MUT--GO (2000 + 100 + 100 U), with a high AMG level.
• The system demonstrated a wide linear range for starch calibration (1 x 10(-4)-0.1% m/v).
• The biosensor exhibited excellent thermal stability between 30-70 degrees C and promising operational properties.

Conclusions:

• A tri-enzyme electrode, optimized with a high concentration of amyloglucosidase, is effective for starch determination in flowing streams.
• Pre-treatment with soluble alpha-amylase significantly enhances starch signal detection compared to immobilized alpha-amylase.
• The developed biosensor offers a sensitive, stable, and reliable method for starch analysis in various applications.