Characterization of pectinase activity for enology from yeasts occurring in Argentine Bonarda grape.

MERÍN, MARÍA GABRIELA; MARTÍN, MARÍA CAROLINA; RANTSIOU, KALLIOPI; COCOLIN, LUCA; MORATA DE AMBROSINI, VILMA INÉS

BRAZILIAN JOURNAL OF MICROBIOLOGY

SOC BRASILEIRA MICROBIOLOGIA

Año: 2015 vol. 46 p. 815 - 823

1517-8382

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, at12 ºC, and under ethanol and SO2 concentrations usually found in vinifications34 (pectinase activity around 1.1 U/mL). This strain also produced cellulase activity at 12 ºC 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.