title: Highly cold-active pectinases under wine-like conditions from non-Saccharomyces yeasts for enzymatic production during winemaking.
abstract: The influence of oenological factors on cold-active pectinases from 15 preselected indigenous yeasts belonging to Aureobasidium pullulans, Filobasidium capsuligenum, Rhodotorula dairenensis, Cryptococcus saitoi and Saccharomyces cerevisiae was investigated. Pectinolytic enzymes were constitutive or partially constitutive; and high glucose concentration (200 g l(-1) ) did not affect or increased pectinase production at 12°C and pH 3·5 (up to 113·9 U mg(-1) ) only in A. pullulans strains. SO2 (120 mg l(-1) ) slightly affected the growth of A. pullulans strains but did not affect pectinase production levels. Ethanol (15%) barely affected pectinase activity of A. pullulans strains but diminished relative activity to 12-79% of basidiomycetous yeasts. Moreover, non-Saccharomyces strains showed promising properties of oenological interest. This study demonstrates that cold-active pectinases from some A. pullulans strains were able to remain active at glucose, ethanol and SO2 concentrations usually found in vinification, and suggests their potential use as processing aids for low-temperature winemaking.
  
  
  CONCLUSIONS
  Nowadays, there is increasing interest in low-temperature winemaking. Nevertheless, commercial oenological pectinases, produced by fungi, are rarely active at low temperatures. Cold-active pectinases that are stable under vinification conditions are needed. This study indicated that cold-active and acid-tolerant pectinases from non-Saccharomcyes yeasts were able to remain active at glucose, ethanol and SO2 concentrations usually found in winemaking. Furthermore, not only are these yeasts a source of cold-active pectinases, but the yeasts themselves are also potential adjunct cultures for oenology to produce these enzymes during cold-winemaking.
authors.affiliation: Facultad de Ciencias Aplicadas a la Industria, Universidad Nacional de Cuyo, San Rafael, Mendoza, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, San Rafael, Mendoza, Argentina.
authors.forename: M G
authors.initials: MG
authors.lastname: Merín
authors.forename: V I
authors.initials: VI
authors.lastname: Morata de Ambrosini
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D003080:Cold Temperature; D000431:Ethanol / Q000737:chemistry; D005658:Fungi; D005947:Glucose / Q000737:chemistry; D010368:Pectins / Q000378:metabolism*; D011096:Polygalacturonase / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013458:Sulfur Dioxide / Q000737:chemistry; D014920:Wine / Q000382:microbiology*
chemical_list: D013458:Sulfur Dioxide; D000431:Ethanol; D010368:Pectins; D011096:Polygalacturonase; D005947:Glucose
keywords: Aureobasidium pullulans; cold-active pectinases; enzyme inhibitors; low-temperature winemaking; oenological pectinases; pectinolytic yeasts