Lighting up wine spoilage in real time with novel biosensor

Researchers have built a living biosensor made of bacteria that lights up when it detects acetic acid, the main chemical signal that wine is starting to spoil. It works in real time, even in high-alcohol conditions, to help wineries catch problems early, before flavour and quality are damaged.

The biological sensor that can detect wine spoilage at an early stage has been developed by a research team led by Hebrew University PhD student Yulia Melnik-Kesler, under the guidance of Professor Yael Helman, and in collaboration with Professor Oded Shoseyov. The approach could provide a simpler alternative to lab testing and strengthen quality control across fermentation-based industries — potentially saving producers and consumers from costly quality losses.

Wine spoilage is often caused by the build-up of acetic acid, the compound responsible for vinegar-like smells and sour flavours. Once acetic acid levels rise, the fermentation process can stall and the wine may become undrinkable. Current methods for measuring acetic acid rely on laboratory techniques such as gas chromatography and liquid chromatography, which are expensive, slow and require liquid samples. These limitations can make it difficult for wineries to monitor fermentation in real time and react before damage is done.

To address this challenge, Helman’s team created a living biosensor made from engineered bacteria that glow in response to acetic acid. The system uses a natural bacterial regulator called YwbIR, originally found in Bacillus subtilis, which, once transcribed in the biosensor, activates a light-producing gene when it detects acetic acid. When acetic acid is present, the biosensor emits a measurable luminescent signal, allowing accurate quantification of the compound.

In laboratory tests, the biosensor showed a strong and linear response to acetic acid levels between 0 and 1 g/L. This range is critical for winemakers, as spoilage typically begins when levels reach approximately 0.7 g/L. At these spoilage-relevant concentrations, the signal increased by five to eight times, providing a clear warning long before the wine becomes undrinkable.

The sensor works not only in liquid, but also in the air above the wine. This means it can detect volatile acetic acid in the headspace of a wine bottle or fermentation tank without opening it. In tests with commercial red and white wines, the biosensor successfully distinguished normal wine from wine that had been artificially spoiled by added acetic acid, producing a clear increase in light output within two hours.

Unlike many electronic or optical sensors, the new biosensor is claimed to remain reliable even in high-alcohol environments. It has functioned accurately in wines containing up to 14.5% alcohol, a condition that typically interferes with conventional detection systems.

Beyond winemaking, the researchers believe the technology could have much wider applications. Acetic acid is an important indicator in many fermentation-based industries, including food production and biofuels. It is also emerging as a biomarker for certain diseases, meaning future versions of the biosensor could potentially be adapted for non-invasive medical diagnostics, such as breath analysis.

“This system allows us to detect acetic acid in real time, without complicated equipment or sample processing,” Helman said. “It opens the door to affordable, onsite monitoring of fermentation quality and, in the future, may even support medical diagnostics based on volatile biomarkers.”

For more information, the study has been published in Microbial Biotechnology.

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