title: Characterization of α-rhamnosidase activity from a Patagonian Pichia guilliermondii wine strain.
abstract: OBJECTIVE
  The purpose of this study was to characterize the α-l-rhamnosidase of Pichia guilliermondii NPCC1053 indigenous wine strain from North-Patagonian region.
  
  
  RESULTS
  The optimization of yeast culture conditions was carried out and the effects of oenological parameters on α-l-rhamnosidase activity were evaluated. Additionally, the effect of direct contact with must and wine on α-l-rhamnosidase activity was assayed. This strain showed an intracellular inducible α-l-rhamnosidase activity. This enzyme was active at pH, glucose and SO(2) concentrations usually found at the beginning of the fermentation as well as retained high levels of activity after 24 h of incubation in must. Furthermore, P. guilliermondiiα-l-rhamnosidase was able to release monoterpenols and alcohols from grape glycosidic extracts.
  
  
  CONCLUSIONS
  The α-l-rhamnosidase belonging to P. guilliermondii indigenous wine yeast strain showed mainly an intracellular location and evidenced interesting oenological characteristics.
  
  
  CONCLUSIONS
  This study contributes to the knowledge of α-l-rhamnosidases from yeast origin because at present, there are few reports about this enzymatic activity in these micro-organisms. In addition, this work is relevant to the regional wine industry considering that this enzyme could be used in the production of more aromatic young wines.
authors.affiliation: Departamento de Química, Laboratorio de Microbiología y Biotecnología, Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, Neuquén, Argentina.
authors.forename: M E
authors.initials: ME
authors.lastname: Rodríguez
authors.forename: C A
authors.initials: CA
authors.lastname: Lopes
authors.forename: S
authors.initials: S
authors.lastname: Valles
authors.forename: A C
authors.initials: AC
authors.lastname: Caballero
mesh_terms: D001118:Argentina; D003470:Culture Media; D005285:Fermentation; D006026:Glycoside Hydrolases / Q000378:metabolism*; D010843:Pichia / Q000201:enzymology* / Q000254:growth & development; D014920:Wine / Q000382:microbiology*
chemical_list: D003470:Culture Media; D006026:Glycoside Hydrolases; C022525:alpha-L-rhamnosidase