Yeasts specificity

Figure 10.29 Diagram of tRNA from yeast, specific for alanine. I, inosine V pseudouridine mG, methylguanosine m2G, dimethylguanosine T, ribothymidine hU, dihydrouridine ml, methylinosine.

Further calculations were performed to quantify the specific enzymatic activity of the WRP45073A1 yeasts. Yeast specific activity in the TIM (from 0.05 0.04 x 10 10 to 3.36 0.86 x 10 10pmol/celFmin, depending on the digestive compartment and the sampling time [29]) was close to that observed in classical batch cultures,... 

Demi et al. [358, 359] and Prillinger et al. [216] isolated many different tremelloid yeasts specifically from spermogonia of different mst fungi. 

Fusel alcohols (1-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 1-hexanol, 2-phenyl-ethanol) were actually among the first aroma constituents studied, as early gas chromatographic research had indicated, erroneously, that these compounds represented the predominant volatile fraction in wines (28). Yeast-specific fusel alcohol production has been studied by a number of researchers (31,33,37-39), all of whom found production differences among yeast strains. Unfortunately yeast strains have not usually been replicated among studies an exception is the work of Delteil and Jarry (57) and Kunkee and Vilas (39). Their results for the fiisel alcohol isobutanol (2-methyl-1-propanol) are shown in Table I. Soufleros and Bertrand (55) studied fifty different yeast strains unfortunately their data do not allow for statistical analysis. Mateo and coworkers (38) examined ten... 

Yeast Specific activity4 PFKC Activities GPDHd Ratio of GPDH/PFK... 

Scale Very little pure enzyme or bacteria may be needed in contrast to the large quantities of yeast. Specificity A pure enzyme normally catalyses only one reaction while a living organism contains many enzymes and may catalyse many reactions. 

A rapid start by the yeast and a nicely progressing fermentation necessitate that the wort composition and the condition of the yeast meet certain requirements. Wort and yeast specifications important for favorable propagation and good fermentation performance are presented in Table 5.8. 

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