Alcohol Sensor

Continous measurements of ethyl alcohol concentration in culture broth are required for fermentation industries. Furthermore, in the cultivation of yeasts using sugar as a carbon source it is well known that ethyl alcohol as a byproduct decreases the sugar basis yield of whole cells. In the cultivation of microorganisms using methyl alcohol as a carbon source, the concentration of methyl alcohol must be maintained at the optimum level to avoid substrate inhibition.

It is well known that many micro-organisms use alcohols as carbon sources. Assimilation of alcohols by micro-organism can be determined from the respiration activity of micro-organisms. The respiration activity is directly measured with an oxygen electrode. Therefore, it is possible to construct a microbial sensor for alcohols using immobilized micro-organisms and a oxygen electrode. A microbial electrode consisting of immobilized yeasts or bacteria, a gas permeable teflon membrane and an oxygen electrode can be prepared for the determination of methyl and ethyl alcohol. Furthermore, the microbial sensor can be applied to continuous determination of alcohols in a fermentation broth.

To test the reliability of the alcohol sensor an experiment was conducted using both a microbial sensor for ethyl alcohol and by gas chromatography. Satisfactory comparative results were obtained between them, thus proving the biosensor useful.