title: Characterization of pectinase activity for enology from yeasts occurring in Argentine Bonarda grape.
abstract: Pectinolytic enzymes are greatly important in winemaking due to their ability to degrade pectic polymers from grape, contributing to enhance process efficiency and wine quality. This study aimed to analyze the occurrence of pectinolytic yeasts during spontaneous fermentation of Argentine Bonarda grape, to select yeasts that produce extracellular pectinases and to characterize their pectinolytic activity under wine-like conditions. Isolated yeasts were grouped using PCR-DGGE and identified by partial sequencing of 26S rRNA gene. Isolates comprised 7 genera, with Aureobasidium pullulans as the most predominant pectinolytic species, followed by Rhodotorula dairenensis and Cryptococcus saitoi. No pectinolytic activity was detected among ascomycetous yeasts isolated on grapes and during fermentation, suggesting a low occurrence of pectinolytic yeast species in wine fermentation ecosystem. This is the first study reporting R. dairenensis and Cr. saitoi species with pectinolytic activity. R. dairenensis GM-15 produced pectinases that proved to be highly active at grape pH, at 12 °C, and under ethanol and SO2 concentrations usually found in vinifications (pectinase activity around 1.1 U/mL). This strain also produced cellulase activity at 12 °C and pH 3.5, but did not produce β-glucosidase activity under these conditions. The strain showed encouraging enological properties for its potential use in low-temperature winemaking.
authors.affiliation: Facultad de Ciencias Aplicadas a la Industria, Universidad Nacional de Cuyo, Mendoza, Argentina . ; Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina .
authors.forename: María Gabriela
authors.initials: MG
authors.lastname: Merín
authors.affiliation: Facultad de Ciencias Aplicadas a la Industria, Universidad Nacional de Cuyo, Mendoza, Argentina . ; Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina .
authors.forename: María Carolina
authors.initials: MC
authors.lastname: Martín
authors.affiliation: Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Torino, Italy .
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Rantsiou
authors.affiliation: Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Torino, Italy .
authors.forename: Luca
authors.initials: L
authors.lastname: Cocolin
authors.affiliation: Facultad de Ciencias Aplicadas a la Industria, Universidad Nacional de Cuyo, Mendoza, Argentina . ; Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina .
authors.forename: Vilma Inés Morata
authors.initials: VI
authors.lastname: de Ambrosini
mesh_terms: D001118:Argentina; D001203:Ascomycota / Q000201:enzymology* / Q000302:isolation & purification; D003454:Cryptococcus / Q000201:enzymology* / Q000302:isolation & purification; D005285:Fermentation / Q000502:physiology; D008969:Molecular Sequence Data; D058889:Molecular Typing; D016533:Mycological Typing Techniques; D010368:Pectins / Q000378:metabolism; D011096:Polygalacturonase / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012335:RNA, Ribosomal / Q000235:genetics; D012248:Rhodotorula / Q000201:enzymology* / Q000302:isolation & purification; D027843:Vitis / Q000382:microbiology*; D014920:Wine / Q000382:microbiology*
chemical_list: D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S; D010368:Pectins; D011096:Polygalacturonase
keywords: Aureobasidium pullulans; Cryptococcus saitoi; Rhodotorula dairenensis; pectinolytic activity; winemaking