Microbial biosensor for free fatty acids using an oxygen electrode based on thick film technology

Area of Science:

• Biotechnology and Biosensor Development
• Analytical Chemistry
• Food Science

Background:

• Microbial biosensors offer a promising approach for analyzing complex biological samples.
• Traditional microbial sensors often suffer from slow response times and instability.
• Developing robust and efficient biosensors is crucial for accurate food quality assessment.

Purpose of the Study:

• To develop a stable and sensitive microbial biosensor for the determination of free fatty acids in milk.
• To optimize immobilization techniques and operational parameters for enhanced sensor performance.
• To overcome the limitations of long response and recovery times in conventional microbial sensors.

Main Methods:

• Immobilization of Arthrobacter nicotianae microorganisms in Ca-alginate directly onto an electrode surface.
• Monitoring microbial respiratory activity via oxygen consumption at -600 mV vs. Ag/AgCl reference electrode.
• Utilizing thick film technology for biosensor fabrication and a batch system for analysis.

Main Results:

• The biosensor demonstrated excellent linearity for free short-chain fatty acids (9.5–165.5 µM, r=0.99920), with butyric acid as the primary target.
• Achieved rapid response times of approximately 3 minutes without requiring a dialysis membrane.
• Showcased high sensitivity and recovery rates (98–113%) for butyric acid in milk samples with a 1:200 dilution.

Conclusions:

• The developed microbial biosensor provides a fast, sensitive, and stable method for free fatty acid quantification in milk.
• Eliminating the need for a dialysis membrane significantly improved response times and sensitivity.
• This technology effectively addresses and overcomes common limitations associated with microbial biosensors.