A kinetic study of the alcoholic fermentation of grape juice

✍ Scribed by I. Holzberg; R. K. Finn; K. H. Steinkraus

• Publisher: John Wiley and Sons
• Year: 1967
• Tongue: English
• Weight: 515 KB
• Volume: 9
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.260090312

✦ Synopsis

The alcoholic fermentation of grape juice by a wine yeast was studied batchwise a t p H 3.6 and 4.05 to develop kinetic equations relating cell concentration, N , to product concentration, P. I n the exponential growth phase

where A , B, and C are constants, and p is the specific growth rate. I n the station- ary phase, where the cell population is constant, apiclt = B(P, -P ) was found to apply. This equation, which incorporates a stoichiometric constant, P,, predicted correctly the operation of a continuous fermentor a t pH 3.6 and a t 4.0.5. To study more fully the effect of alcohol concentration on yeast growth, a continuous fermentor was used in which the grape juice feed was supplemented with pure alcohol. At pH 3.6 the specific growth rate varied as, (l/N)(dN/dt) = pmax[l -0.235 ( P -2.6)l There wab no growth inhibition below an alcohol concentration of 2.6 g./lOO cc., but inhibition was complete above 6.85 g./100 cc. This is a modified form of the relation suggested by Hinshelwood.' The data suggest that growth in batch culture was limited not only by alcohol but also by some other factor, probably a nutritional deficiency.