Detection of Spoilage-Associated Acetic Acid Levels Using a Transcription-Based Whole-Cell Biosensor

Area of Science:

• Biotechnology
• Biosensors
• Fermentation Monitoring

Background:

• Acetic acid (AC) accumulation during fermentation can cause spoilage.
• Conventional AC detection methods are costly, time-consuming, and not suitable for real-time monitoring.

Purpose of the Study:

• To develop a low-cost, whole-cell bacterial biosensor for real-time acetic acid detection.
• To enable early identification of AC buildup in fermentation processes.

Main Methods:

• Utilized the YwbIR transcriptional regulator from Bacillus subtilis to design a bacterial biosensor.
• Assessed biosensor sensitivity, linearity, and functionality in ethanol-rich matrices.
• Performed specificity assays and molecular docking to evaluate affinity for AC.

Main Results:

• The biosensor demonstrated high sensitivity with a linear response (R² = 0.97) from 0 to 1.0 g/L.
• Achieved 5-8 fold induction at wine spoilage-relevant AC concentrations.
• Confirmed functionality in up to 14.5% v/v ethanol and headspace detection capability, with high specificity for AC.

Conclusions:

• The developed bacterial biosensor provides an effective, low-cost solution for real-time AC monitoring.
• Enables timely intervention to prevent spoilage and enhance quality assurance in food and beverage production.
• Offers a viable alternative to conventional methods for AC detection in fermentation.