Evaluation of polygalacturonase activity in Saccharomyces cerevisiae wine strains.
A total of 61 S. cerevisiae strains, 60 of them isolated from wine ecosystems, were evaluated for the presence of the gene encoding endopolygalacturonase (PGU1) and for polygalacturonase (PG) activity. Nine strains lack the gene PGU1 and did not exhibit PG activity on plate assays. Of the 52 strains showing an amplified band corresponding to the size of PGU1 gene, only 36 degraded polygalacturonic acid (PGA) and 17 did not degrade it at any of the pH values used. The coding region of the PGU1 gene (ORF YJR153w) was not present in some PG activity negative strains. The S. cerevisiae UCLMS-39 strain was selected for its specific activity at different pHs, temperatures and oenological parameters. The temperature and pH optima were 50 degrees C and 3.5-5.5 respectively and it was only affected by ethanol. The PGU1 gene was cloned and sequenced. The production of a biologically functional endoPG in S. cerevisiae UCLMS-39 brings us a step closer to improving the qualities of outstanding enological yeasts naturally lacking PG activity.
Departmento de Quimica Analitica y Technologia de Alimentos, Facultad de Quimicas, Universidad de Castilla-La Mancha, Campus Universitario, Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain.
M
M
Fernández-González
J F
JF
Ubeda
T G
TG
Vasudevan
R R
RR
Cordero Otero
A I
AI
Briones
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D010368:Pectins / Q000378:metabolism; D011096:Polygalacturonase / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D014920:Wine / Q000382:microbiology*
D010368:Pectins; C493097:PGU1 protein, S cerevisiae; D011096:Polygalacturonase