Factors affecting the production of 4-ethylphenol by the yeast Dekkera bruxellensis in enological conditions Original Research Article

The conversion of p-coumaric acid into 4-ethylphenol was studied in Dekkera bruxellensis ISA 1791 under defined conditions in synthetic media. The production of 4-ethylphenol occurred roughly between mid-exponential growth phase and the beginning of the stationary phase. This behaviour was observed when glucose was the only energy and carbon source, the conversion rate being close to 90%. Ethanol, as the single energy source, yielded conversion rates close to 80% while in the presence of trehalose and acetic acid conversion rates lower than 10% were obtained. The production of 4-ethylphenol was not observed when the cells were maintained in buffer solution without carbon and energy sources. The precursor of 4-ethylphenol, p-coumaric acid, was not utilized as energy and carbon source. Furthermore, it was shown that 4-vinylphenol may be used as a precursor of 4-ethylphenol in the absence of p-coumaric acid.