A multi-phase approach to select new wine yeast strains with enhanced fermentative fitness and glutathione production.

The genetic improvement of winemaking yeasts is a virtually infinite process, as the design of new strains must always cope with varied and ever-evolving production contexts. Good wine yeasts must feature both good primary traits, which are related to the overall fermentative fitness of the strain, and secondary traits, which provide accessory features augmenting its technological value. In this context, the superiority of "blind," genetic improvement techniques, as those based on the direct selection of the desired phenotype without prior knowledge of the genotype, was widely proven.

Genetic variation and expression changes associated with molybdate resistance from a glutathione producing wine strain of Saccharomyces cerevisiae.

Glutathione (GSH) production during wine fermentation is a desirable trait as it can limit must and wine oxidation and protect various aromatic compounds. UMCC 2581 is a Saccharomyces cerevisiae wine strain with enhanced GSH content at the end of wine fermentation. This strain was previously derived by selection for molybdate resistance following a sexual cycle of UMCC 855 using an evolution-based strategy.

High-glutathione producing yeasts obtained by genetic improvement strategies: a focus on adaptive evolution approaches for novel wine strains.

Glutathione (GSH) is the most abundant non-protein thiol in living organisms. Due to its important antioxidant role, it is widely used in medicine, as a food additive, and in the cosmetic industry. Recently, GSH has received growing attention in winemaking because of its ability to control oxidative spoilage damage and to protect various aromatic compounds.

Evolved Saccharomyces cerevisiae wine strains with enhanced glutathione production obtained by an evolution-based strategy.

In winemaking, the application of glutathione (GSH) has been the subject of ever-growing interest because of its important role in limiting must and wine oxidation and in protecting various aromatic compounds. Glutathione concentration in wine is highly variable, involving as it does several factors from must, through alcoholic fermentation, to yeast strain activity. Consequently, the development of new wine yeast strains able to improve flavor stability is in great demand.

Regulated expression systems for the development of whole-cell biocatalysts expressing oxidative enzymes in a sequential manner.

This work reports the preparation of two recombinant strains each containing two enzymatic activities mutually expressed through regulated systems for production of functionalized epoxides in one-pot reactions. One strain was Pseudomonas putida PaW340, containing the gene coding for styrene monooxygenase (SMO) from Pseudomonas fluorescens ST under the auto-inducing Ptou promoter and the TouR regulator of Pseudomonas sp. OX1 and the gene coding for naphthalene dihydrodiol dehydrogenase (NDDH) from P.