Analytical characterisation of yeast cell walls by lectin-binding flow cytometry and extraction-based polysaccharide analysis.

Accurate profiling of yeast cell-wall polysaccharides (PS) remains analytically challenging because different methods interrogate different levels of cell-wall organisation. In this study, lectin-binding flow cytometry and extraction-based chemical analysis were comparatively evaluated across 10 representative yeast strains. Flow cytometry revealed marked strain-dependent variation in forward scatter (FSC), side scatter (SSC), and median of lectin fluorescence intensity (MFI), whereas extraction-based analysis showed substantial differences in PS yield, monosaccharide composition, and molecular weight distribution. Using lg-transformed data, Pearson correlation and partial least squares regression (PLSR) analyses showed that FSC and SSC were strongly associated with cell-normalised extractable mannose content (r = 0.89 and 0.88, respectively) and contributed most to its prediction. By contrast, MFI was more strongly related to the mannose to glucose molar ratio (r = 0.90) than to extractable mannose content (r = 0.70), providing strain-specific biochemical information. These findings demonstrate that flow cytometry and extraction-based analysis are complementary approaches. Scatter-based parameters mainly reflect absolute PS abundance associated with cell size, whereas MFI rapidly reflects surface lectin-binding characteristics and PS composition. The combined use of both methods therefore provides a more complete framework for yeast cell-wall characterisation.