Comparative characterization of endo-polygalacturonase (Pgu1) from Saccharomyces cerevisiae and Saccharomyces paradoxus under winemaking conditions
Abstract
Wine strains of Saccharomyces cerevisiae have no to weak natural pectinase activity, despite their genetic ability to secrete an endo-polygalacturonase. The addition of external pectinase of fungal origin has therefore become a common step of winemaking in order to enhance the extraction of compounds located in the grape berry skins during maceration and to ease wine clarification after maturation. Recently, the strong pectinase activity of a wine strain of Saccharomyces paradoxus has been reported. In this study, the endo-polygalacturonase-encoding gene of S. paradoxus was sequenced and its activity was characterised, compared with that of S. cerevisiae and tested under winemaking conditions through overexpression of both genes individually in S. cerevisiae. A few differences in the amino acids sequences between the two proteins were revealed and the activity of the Pgu1 enzyme of S. paradoxus was shown to be weaker under winemaking conditions. Clear indicators of extracellular activity were observed in the wines made with both recombinant strains (i.e. enzyme activity in cell-free wine, higher methanol concentration and higher free-run wine), but the actual composition of the wines fermented with the mutants was only sparingly altered. Although unexpectedly found in lower concentrations in the latter wines, phenolic compounds were shown to be the most discriminatory components. Overexpressing the PGU1 gene of S. paradoxus or that of S. cerevisiae did not make much difference, showing that the higher activity of S. paradoxus strains under laboratory conditions could be due to a different regulation mechanism rather than to a different sequence of PGU1. © 2011 Springer-Verlag.
Description
Keywords
Endo-polygalacturonase activity, PGU1, Saccharomyces paradoxus, Wine, Cell-free, Endo-polygalacturonase activity, Extracellular activity, Grape berry, Laboratory conditions, Methanol concentration, Over-expression, Pectinases, PGU1, Phenolic compounds, Recombinant strains, Regulation mechanisms, S.cerevisiae, Saccharomyces, Wine clarification, Wine strains, Amino acids, Fruits, Gene encoding, Methanol, Phenols, Wine, Yeast, Enzyme activity, methanol, polygalacturonase, comparative study, concentration (composition), discriminant analysis, enzyme activity, fermentation, gene expression, laboratory method, maturation, methanol, mutation, protein, recombination, vine, yeast, amino acid sequence, article, enzyme activity, fungal gene, gene overexpression, nucleotide sequence, regulatory mechanism, Saccharomyces, Saccharomyces cerevisiae, Saccharomyces paradoxus, wine, wine industry, Saccharomyces cerevisiae, Saccharomyces paradoxus, Vitaceae
Citation
Applied Microbiology and Biotechnology
91
3
http://www.scopus.com/inward/record.url?eid=2-s2.0-79960709492&partnerID=40&md5=5dbd9a4d5bb3412e884937ac77128615
91
3
http://www.scopus.com/inward/record.url?eid=2-s2.0-79960709492&partnerID=40&md5=5dbd9a4d5bb3412e884937ac77128615