Flocculation gene variability in industrial brewer's yeast strains.

The brewer's yeast genome encodes a 'Flo' flocculin family responsible for flocculation. Controlled floc formation or flocculation at the end of fermentation is of great importance in the brewing industry since it is a cost-effective and environmental-friendly technique to separate yeast cells from the final beer. FLO genes have the notable capacity to evolve and diverge many times faster than other genes.

Stability of high cell density brewery fermentations during serial repitching.

The volumetric productivity of the beer fermentation process can be increased by using a higher pitching rate (i.e. higher inoculum size).

The influence of yeast oxygenation prior to brewery fermentation on yeast metabolism and the oxidative stress response.

Yeast preoxygenation can confer important advantages to brewery fermentations by means of omitting the need to oxygenate the wort. However, the impact of yeast preoxygenation on yeast metabolism has never been assessed systematically. Therefore, expression analysis was performed of genes that are of importance in oxygen-dependent pathways, oxidative stress response and general stress response during 8 h of preoxygenation.

Phenotypic diversity of Flo protein family-mediated adhesion in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae genome encodes a Flo (flocculin) adhesin family responsible for cell-cell and cell-surface adherence. In commonly used laboratory strains, these FLO genes are transcriptionally silent, because of a nonsense mutation in the transcriptional activator FLO8, concealing the potential phenotypic diversity of fungal adhesion. Here, we analyse the distinct adhesion characteristics conferred by each of the five FLO genes in the S288C strain and compare these phenotypes with a strain containing a functional copy of FLO8.

Immobilized yeast cell systems for continuous fermentation applications.

In several yeast-related industries, continuous fermentation systems offer important economical advantages in comparison with traditional systems. Fermentation rates are significantly improved, especially when continuous fermentation is combined with cell immobilization techniques to increase the yeast concentration in the fermentor. Hence the technique holds a great promise for the efficient production of fermented beverages, such as beer, wine and cider as well as bio-ethanol.