Optimised Extraction and Preliminary Characterisation of Mannoproteins from Non-Saccharomyces Wine Yeasts

Abstract

The exogenous application of yeast-derived mannoproteins presents many opportunities for the improvement of wine technological and oenological properties. Their isolation from the cell wall of Saccharomycescerevisiae has been well studied. However, investigations into the efficiency of extraction methods from non-Saccharomyces yeasts are necessary to explore the heterogeneity in structure and composition that varies between yeast species, which may influence wine properties such as clarity and mouthfeel. In this study, nine yeast strains were screened for cell wall mannoprotein content using fluorescence microscopy techniques. Four species were subsequently exposed to a combination of mechanical and enzymatic extraction methods to optimize mannoprotein yield. Yeast cells subjected to 4 min of ultrasound treatment applied at 80% of the maximum possible amplitude with a 50% duty cycle, followed by an enzymatic treatment of 4000 U lyticase per g dry cells weight, showed the highest mannoprotein-rich yield from all species. Furthermore, preliminary evaluation of the obtained extracts revealed differences in carbohydrate/protein ratios between species and with increased enzyme incubation time. The results obtained in this study form an important step towards further characterization of extraction treatment impact and yeast species effect on the isolated mannoproteins, and their subsequent influence on wine properties.

Characterization of Mannoprotein Structural Diversity in Wine Yeast Species

“…This research investigated some of the compositional differences that exist between MPs isolated from different yeast species, particularly in terms of their protein profiles, mannose/glucose ratios, polysaccharide size distribution, and protein/carbohydrate ratios. MP-rich preparations from SB62, SC01, MF77, and TD70 were obtained through ultrasound and β-1,3-glucanase treatment based on the method optimized previously . A commercial MP formulation, LMP, was used for comparison purposes.…”

“…MPs were extracted from liquid cultures of the following strains: Saccharomyces boulardii (SB62), Saccharomyces cerevisiae (SC01), Metschnikowia fructicola (MF77), and T. delbrueckii (TD70) obtained from the yeast culture collection of Lallemand Inc. (Montreal, QC, Canada). Yeast strains were cultivated in an enrichment medium [yeast extract (10 g/L), peptone (20 g/L), and glucose (20 g/L)] prepared in 0.1 M McIlvaine's buffer adjusted to pH 5 and cultured at 30 °C with shaking at 120 rpm, as described by Snyman et al 21 (2021), and cells were collected through centrifugation after 48 h of incubation. Cells were subsequently resuspended in 0.1 M phosphate buffer, pH 6.5, to a volume of 200 mL at a concentration of 2.5 × 10 8 cells/mL.…”

Production and Characterization of a Bioemulsifier Derived from Microorganisms with Potential Application in the Food Industry

“…The most abundant type of mannoprotein is structural, which consists of a small protein portion linked to a larger carbohydrate portion (mannopyranosyl), whereas enzymatic mannoproteins contain more protein moieties. Not only are these molecules effective emulsifiers, but they have also been linked to the stimulation of host immunity via the activation of immune cells and proteins as well as the induction of antibody production [24,25]. Figure 2 depicts the structure and mechanism of action of a number of significant emulsifiers produced by microorganisms through biotechnology processes.…”

Red and white wine lees as a novel source of emulsifiers and foaming agents

“…The extracts from lab-grown yeasts showed, in three out of four cases, a significantly higher protein content when compared to the correspondent extracts from wine lees (p ≤ 0.05). This occurrence seems attributable to the partial degradation that yeast cells in wine lees would have undergone during winemaking, which possibly caused the release of cytoplasmic proteins which in contrast should be present in the extracts of the lab-grown yeasts (Snyman, Mekoue Nguela, Sieczkowski, Marangon, & Divol, 2021). Another possible explanation can be related to the fact that the extracts from wine lees include larger amounts of other compounds (e.g.…”