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.

Yeasts found in vineyards and wineries

“…Although not yet tested at larger scale, R . dairenensis has been shown to produce pectinase enzymes which could be applied during winemaking (Merin et al ., ).…”

“…In winemaking A . pullulans application has focused on the production of specific enzymes, including pectinase, which has several roles in wine production, including clarification (Merin et al ., ), and β ‐glucosidase, which has been shown to improve wine aroma (Baffi et al ., ).…”

“…A. pullulans is a darkly pigmented, yeast-like fungus that is present in a variety of environmental locations and as a epi-and endophyte of plants, including grapevine. In winemaking A. pullulans application has focused on the production of specific enzymes, including pectinase, which has several roles in wine production, including clarification (Merin et al, 2015), and β-glucosidase, which has been shown to improve wine aroma (Baffi et al, 2013).…”

Evaluation of Macerating Pectinase Enzyme Activity under Various Temperature, pH and Ethanol Regimes

“…Ethanol will inhibit activities of some enzymes such as catalase [48], however, and its action was attributed to the binding of ethanol with the enzyme, thereby inhibiting the reaction. Others have shown no effect of ethanol on pectinases in fermentations, suggesting wide variability of tolerance [49].…”

Screening a bacterium and its effect on the biological degumming of ramie and kenaf

“…We dibbled 0.5 μL of the suspensions on the selective medium, and then inverted and incubated at 35 °C for 18-20 h. Lugol iodine solution turned the background dark brown; as a result, clear haloes appeared around the active pectin-degrading strains. Diameter ratios H/C of the pectinolytic bacteria were calculated using the data obtained by the diameters of the bacterial colonies (C) and their hydrolysis circles (H) (Merin et al, 2015).…”