A comparative study for the isolation and characterization of mannoproteins from Saccharomyces cerevisiae yeast cell wall

Cell wall yeast, recovered upon the production of yeast extract, was investigated as an abundant source of mannoproteins. Selected isolation methods were evaluated for the recovery of mannoproteins, in terms of yield, mannan and protein recovery yield, mannoproteins content and mannan to protein ratio in extracted mannoproteins. The results showed that heat treatment and sodium dodecyl sulfate (SDS) extraction led to a lower yield compared to the enzymatic treatment; and no glycosylated proteins could be obtained upon the SDS extraction. As compared to other methods, the enzymatic approach, based on the use of Zymolyase®, exhibiting a high β-1,3-glucanase activity, resulted in the highest yield, mannoproteins content and mannan to protein ratio. A 5-level, 2-variable central composite rotatable design contributed to the better understanding of the effects of independent variables, reaction time and enzyme units, on the efficiency of the enzymatic treatment and to the better modulation of their actions. The effects of enzyme units and reaction time on the mannoproteins content and the mannan to protein ratio exhibited the same patterns. Comparison of predicted and experimental values validated the established predicted models, which can be used to identify the conditions for the isolation of mannoproteins with well-defined molecular properties.