A Fiber-Optic Carbon Dioxide Sensor for Fermentation Monitoring


We have developed a fiber-optic chemical sensor for determining dissolved carbon dioxide and assessed its performance for the on-line monitoring of fermentation. The sensor operates on the Severinghaus pCO2 electrode principle; it consists of a pH sensitive dye (hydroxypyrenetrisulfonic acid, HPTS) in an HCO3 buffer solution entrapped in an expanded PTFE support held at the distal end of an optical fiber by a gas permeable membrane. CO2 crossing the membrane produces a pH change in the indicator solution. This change is related to the external CO2 concentration by the Henderson-Hasselbach equation. The sensor has a reversible working dissolved CO2 dynamic range of 0–0.25 atm. The sensor can be auto-claved without affecting its calibration. Results are presented for the on-line determination of CO2 production in beer fermentation.

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Correspondence to David R. Walt.

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Uttamlal, M., Walt, D. A Fiber-Optic Carbon Dioxide Sensor for Fermentation Monitoring. Nat Biotechnol 13, 597–601 (1995). https://doi.org/10.1038/nbt0695-597

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