Use of a PGU1 recombinant Saccharomyces cerevisiae strain in oenological fermentations

Aim: The aim of this work was the construction of an oenological Saccharomy ces cerevisiae strain able to overexpress the PGU1 gene in order to be used in trial fermentations. Methods and Results: The recombinant strain is able to secrete an active en dopolygalacturonase into the medium leaving its fermentation ability essent ially unchanged. Wines obtained with the recombinant strain and the untrans formed counterpart did not differ in their physicochemical parameters or ma jor sensory characteristics. The time needed for wine filtration was dramat ically reduced in wines elaborated with the PGU1 recombinant strain, and wa s comparable to the filtration time shown by wines elaborated from must sup plemented with fungal pectolytic enzymes. Conclusions: The oenological strain constructed in this work secretes an en dopolygalacturonase into the wine in an efficient manner, resulting in an i mprovement in wine filtration but preserving wine typicality and keeping th e methanol levels unchanged. Significance and Impact of the Study: The PGU1 recombinant strains could be used in oenological fermentations as an alternative to commercial pectolyt ic enzymes of fungal origin.