CONTINUOUS PRODUCTION OF 4-ETHYLGUAIACOL BY IMMOBILIZED CELLS OF SALT-TOLERANT CANDIDA-VERSATILIS IN AN AIRLIFT REACTOR

The effects of pH, temperature, aeration, and residence time on the continuous production of 4-ethyl-guaiacol (4-EG), which is one of the characteristic aroma components in soy sauce, by immobilized cells of the salt-tolerant yeast Candida versatilis were investigated using an airlift reactor. The optimum pH and temperature were about 4.0 and 30-33°C, respectively. The amount of 4-EG in the liquid was constant even during alterations of nitrogen/air ratio in the supplied gas. A large amount of 4-EG (over 20 ppm) was produced at a residence time from 5 to 28 h and 1-3 ppm of 4-EG, which was the optimum concentration in conventional soy souce, was produced at a shorter residence time of 0.5 h. The 4-EG production by immobilized C. versatilis cells using the airlift reactor was stable for 40 d. It was found that the immobilized cell method was effective for the production of 4-EG by C. versatilis cells. © 1990.