Exploring the dynamic between yeast mannoproteins structure and wine stability. Part 1: Polysaccharides part characteristics of S. cerevisiae and non-Saccharomyces mannoproteins.

A thorough characterization of the polysaccharide part of Mannoprotein Pools (MPs) from nine different yeast strains was performed to assess biosynthesis-pathways impact on mannoproteins macromolecular structure and later establish structure-function relationships regarding stabilization properties. The strains comprised one wild-type S. cerevisiae strain, its mutants ΔMnn2 and ΔMnn4 (non-ramified N-glycosylated backbone and lacking mannosyl-phosphorylation, respectively), enological Saccharomyces cerevisiae strains grown in different metabolic conditions (aerobic and anaerobic), and three non-Saccharomyces species: Hanseniaspora vineae, Torulaspora delbrueckii, and Schizosaccharomyces japonicus. Neutral sugars composition for MPs of all strains had mainly mannose but Schizosaccharomyces japonicus strain also presented approximately 33 % of galactose. MPs from non-Saccharomyces strains exhibited significant differences in glycosyl-linkage analysis, especially those from Torulaspora delbrueckii and S. japonicus strains. Global net charge analysis of MP from S. japonicus strain suggests the presence of unknown negatively charged ions. These results dismiss the general N-glycosylated and O-Mannosylated structures obtained from S. cerevisiae. HPSEC-MALLS-QELS-Viscometry analysis revealed higher intrinsic viscosity profiles ([η]xMw) of H. vineae and S. japonicus MPs than S. cerevisiae ones. Metabolic conditions also influenced S. cerevisiae MPs biosynthesis: aerobiosis produced more negatively charged (20C.g, net charge at pH 3.5) and less compact (ρ = 2.8) MPs than anaerobiosis (5C.g and 1.4).