Abstract

ESTELA-ESCALANTE, W.; RYCHTERA, M.; MELZOCH, K.  and  HATTA-SAKODA, B.. Effect of aeration on the fermentative activity of Saccharomyces cerevisiae cultured in apple juice. Rev. Mex. Ing. Quím [online]. 2012, vol.11, n.2, pp.211-226. ISSN 1665-2738.

The influence of aeration on the fermentative activity of Saccharomyces cerevisiaeRTVE V 15-1-416 was studied in order to evaluate the synthesis of fermentation by-products. To achieve this, the strain was cultured in Erlenmeyer flasks and bioreactor containing sterilized and aroma removed apple juice. The chemical compounds produced during fermentations in shaken (200 min-¹) and static (without agitation) flasks and bioreactor, all in batch mode, were determined by GC and HPLC. The results showed that agitation of the culture médium dimishes production of total higher alcohols (316.0±27.5mg/L) compared to static cultivation (557.8±28.1mg/L) and enhances slightly ethyl acétate production (75.0±6.5mg/L), whereas on the contrary, the production of acetic acid and glycerol (266.0±8.0mg/L and 2.9±0.2g/L) were higher compared to shaken cultivation (51.0±4.5mg/L and 0.11±0.05g/L) respectively. Batch cultivations carried out in bioreactor with constant air flow of 0.28vvm reported a specific growth rate (μ) of 0.13h^-1 and maximum concentration of ethanol of 42.3g/L during aerobic fermentation. Aeration promotes cell growth, diminishes ethanol yield and, provokes acetic acid uptake and succinic acid synthesis whereas malic acid and ethanol were consumed after sugar depletion. The best results in terms of sensory acceptability of the fermented beverage were obtained when cultivated statically. Aeration control during fermentation with this strain can be used to control the synthesis of chemical compounds of sensory importance.

Keywords : Saccharomyces cerevisiae; alcoholic fermentation; higher alcohols; ethyl acétate; batch cultivation.

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