Yeasts strain adaptation

Figure 3.12 Persistence of testosterone in sandy loam, loam, and silt loam soil spiked with 1 mg [ C]-testostrone/kg. The middle panel shows residues in soil extracts, whereas the bottom panel represents a loss in androgenicity in the soil extract. Androgenicity was measured using a human androgenicity receptor recombinant yeast strain. (Adapted from Lorenzen et al., 2005.)...

It is important to emphasize that for moderate- to large-scale fermentation plants, bank deposits of suitable yeast strains are necessary to guard against contamination. The capability of propagating active yeast strains adapted to the particular feedstock and conditions used in the process should be maintained to make sufficient inoculum available for fermenter startup after plant upsets and scheduled shutdowns. Also, if yeast cells are separated for recycling as inoculum for fresh feed, the most active cell strata should be selected. 

Budroni, M., Zara, S., Zara, G., Pirino, G., and Mannazzu, I. (2005). Peculiarities of flor strains adapted to Sardinian sherry-like wine aging conditions. FEMS Yeast Res. 5, 951-958. 

Fig. 4.4 Effect of alcoholic fermentation and yeast strain on the concentration of glycoside-derived volatile compounds and of different classes of glycosidic precursors during the fermentation of a model grape juice containing Muscat glycosides. The control refers to a non-fermented sample kept under the same conditions utilized for fermentation, which accounts for add catalysed hydrolysis of glycosides (adapted from Ugliano 2006)...

FIG. 6 Growth of Oenococcus oeni in Chardonnay wines prepared using yeast strains UCLM S325 ( , 50 mg/L total S02), Zymafluor VL1 ( , 33 mg/L total S02), CKS 102 (A, 18 mg/L total S02), EC1118 (X[CN4], 18 mg/L total S02), BKS 104 ( , 15 mg/L total S02), or Saint Georges SI01 (o, 0 mg/L total S02). Concentrations of total S02 in these wines was determined just before bacterial inoculation. (Adapted from Larsen et al., 2003 and with permission from the American Journal of Enology and Viticulture.)... 

Heidenreich, E., Holzmann, V., and Eisler, H. (2004). Polymerase ( dependency of increased adaptive mutation frequencies in nucleotide excision repair-deficient yeast strains. DNA Repair 3, 395-402. 

Figure 9.14 Potential targets for wine yeast strain development. The primary role of wine yeast is to conduct the alcoholic fermentation during which grape sugars (mainly glucose and fructose) are converted into ethanol, carbon dioxide and other minor, but important, metabolites. The main emphasis in strain development programmes is on the development of Saccharomyces cerevisiae strains with improved fermentation, processing and biopreservation abilities, and the capacity to enhance the wholesomeness and sensory quality of wine. It is hoped that such genetically improved yeast strains could enhance cost-effective production of wine with minimised resource inputs, improved quality and low environmental impact. Adapted from Pretorius (2000).

Means in rows with different letters for a given yeast strain are significantly different (p < 0.05). Adapted from Huang et al. (1996) and with the kind permission of the American Journal ofEnology and Viticulture. 

Figure 5.3. Systematic mating ofyeast two-hybrid bait and prey pools. Each yeast ORF was cloned individually into both as a DNA binding domain fusion (bait) and activation domain fusion (prey). The bait fusions were introduced into a MATa strain and the prey fusions were introduced into a MATa strain. The bait and prey fusions were pooled in sets of 96 clones to generate a total of 62 pools of each. The pools were systematically mated (62 x 62) in a total of 3844 crosses. Interacting clones were selected and the bait and prey inserts were PCR amplified and sequenced to determine their identify. Figure adapted from Ito et al. (2001).

Biological. A Pseudomonas strain P6, isolated from a Matapeake silt loam, was grown using a yeast extract. After 8 d, 4-nitroaniline degraded completely to carbon dioxide (Zeyer and Kearney, 1983). In activated sludge inoculum, following a 20-d adaptation period, no degradation... 

In a related application of this approach, Ferea et al. (1999) examined variations in gene expression of progeny during adaptive evolution. The yeast genomes were monitored in evolving strains subjected to growth under... 

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