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Third-generation biosensor for lactose based on newly discovered cellobiose dehydrogenase.
Leonard Stoica1, Roland Ludwig, Dietmar Haltrich
1Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden. leonard.stoica@analykem.lu.se
Analytical Chemistry
|January 18, 2006
Summary
A novel lactose biosensor utilizes cellobiose dehydrogenase (CDH) for highly efficient electron transfer. This biosensor demonstrates excellent sensitivity and stability, offering a promising alternative for lactose detection in various milk products.
Area of Science:
- Biotechnology
- Electrochemistry
- Biosensor Technology
Background:
- Developing sensitive and stable biosensors for lactose detection is crucial for the dairy industry.
- Existing lactose biosensors often face limitations in sensitivity, response time, or operational stability.
- Cellobiose dehydrogenase (CDH) offers potential for enhanced biosensor performance due to its enzymatic properties.
Purpose of the Study:
- To develop and characterize a third-generation lactose biosensor utilizing novel cellobiose dehydrogenases (CDH).
- To investigate the efficiency of direct electron transfer between newly discovered CDHs and a graphite electrode.
- To evaluate the analytical performance and stability of the CDH-based biosensor for lactose quantification.
Main Methods:
- Immobilization of CDH from Trametes villosa and Phanerochaete sordida onto a graphite electrode via physical adsorption.
- Integration of the CDH-modified electrode into a wall-jet amperometric cell within a flow injection system.
- Amperometric detection of lactose and evaluation of sensor parameters including detection limit, sensitivity, response time, and linear range.
Main Results:
- The Phanerochaete sordida CDH-based biosensor exhibited a low detection limit (1 microM) and high sensitivity (1100 microA x mM(-1) x cm(-2)).
- The biosensor demonstrated a rapid response time of 4 seconds and a wide linear range (1-100 microM lactose) with excellent linearity (R^2=0.998).
- The sensor showed high operational stability, maintaining 98% of its initial signal after 11 hours of continuous use, and accurately quantified lactose in milk samples without matrix effects.
Conclusions:
- The developed CDH-based lactose biosensor offers a simple construction and superior analytical characteristics compared to existing methods.
- The high efficiency of direct electron transfer between CDH and the electrode is key to the biosensor's performance.
- This biosensor presents a viable and excellent alternative for routine lactose analysis in food and dairy products.