Characterization of a unique mannan from Starmerella bacillaris for protein stabilization in white wine

Abstract

Yeast cell wall components are valuable biotechnological tools with applications in oenology and beyond [1], [2]. Starmerella bacillaris, a non-Saccharomyces yeast, remains relatively understudied, yet recent discoveries have highlighted distinct metabolic traits among wine yeasts [3] and the promising role of its polysaccharides in winemaking [4]. This study investigated different S. bacillaris strains alongside Saccharomyces cerevisiae as potential sources of functional yeast derivatives for protein stabilization in white wine.

Yeast biomass was cultivated through aerobic fed-batch propagation and mechanically processed to obtain yeast cell walls. To generate distinct polysaccharidic derivatives, yeast cell walls were subjected to various extraction processes. The physicochemical properties of the obtained macromolecular derivatives were characterized using near-infrared (NIR) spectroscopy, HPLC, SDS-PAGE, and high-resolution size-exclusion chromatography (HRSEC). The stabilization efficacy of the obtained derivatives was assessed in white wine through turbidity analysis, identifying a promising product from S. bacillaris. Ultrafiltration was then employed to isolate the active polysaccharide fraction, which underwent further characterization through linkage analysis and nuclear magnetic resonance (NMR) spectroscopy. The fraction was identified as a linear mannan, distinguishing it from the typically branched mannoproteins found in S. cerevisiae-derived cell wall extracts [5].

These findings reveal the unique structural features of S. bacillaris cell walls and their technological potential for alternative protein stabilization strategies in winemaking.

References

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