Fermentative behavior of the Candida stellata yeast under different aeration conditions

The influence of aeration on the fermentative activity of Candida stellata RIVE 3-16-1 was studied. The strain was cultured either in Erlenmeyer flasks or a bioreactor containing sterilized and aroma-removed apple juice. Cultures in Erlenmeyer flasks were done under shaken or static condition, whereas in the bioreactor, a constant air flow regime was kept. Chemical compounds produced during fermentation were determined by GC and HPLC. The agitation of Erlenmeyer flasks increased the production of total higher alcohols as compared to static culture and enhanced dramatically the ethyl acetate production. Meanwhile, the production of acetic acid and glycerol were higher under static culture. Bioreactor fermentation at constant air flow was important to visualize the effect of oxygen on the production of compounds and its impact in the quality of alcoholic beverages. It is reported a specific growth rate of 0.13 h^-1. Aeration promoted the cell growth affecting the ethanol yield. At the end of culture, malic acid naturally present in apple juice and the ethanol produced were consumed after sugar depletion. Moreover, the acetic acid produced at the end of the fermentation served as carbon source too. The best results in terms of acceptability of the fermented beverages were obtained when cultivated statically.