Biotyping Saccharomyces cerevisiae strains using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)

Abstract

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS), a powerful biotyping tool for the identification of bacteria and clinical yeast isolates, was investigated as a method to rapidly identify industrial S. cerevisiae strains. In this study, an optimized sample preparation protocol was devised for the biotyping of S. cerevisiae strains. The results demonstrate that ethanol/formic acid protein extraction, of a cell density of 1 × 108 cells co-crystallized with α-cyano-4-hydroxycinnmaic acid, is required to yield mass spectral profiles that are diagnostic of each strain type. Forty-four S. cerevisiae strains commonly employed in South African fermentation-based industries were biotyped in an attempt to create a yeast reference database within a local context. The data revealed that MALDI-TOF MS can be used for the rapid and accurate identification of laboratory and industrial S. cerevisiae strains.