Assessment of the Brettanomyces bruxellensis metabolome during sulphur dioxide exposure

摘要

Brettanomyces bruxellensis displays a high degree of genotypic and phenotypic polymorphism and is the main yeast species involved in wine spoilage. The innate resistance of 108 B. bruxellensis strains to the antimicrobial agent SO_2 used in winemakingwas investigated. Nineteen strains (17.6%) were sensitive to SO_2, failing to grow at the lowest concentration tested (0.1 mg L~(-1) molecular SO_2). Twenty-nine strains (26.8%) grew at 0.1 mg L~(-1) 42 strains (38.9%) grew at 0.2 mg L~(-1), and 16 strains (14.8%) were able to grow as high as 0.4 mg L~(-1) mol. SO_2. Two strains able to grow in the presence of 0.6 mg L~(-1) mol. SO_2 were further studied by GCMS-TOF analysis to define the metabolic response to SO_2 treatment. Two hundred and fifty-three intracellular metabolites were detected. The main effect observed was a decrease in cytoplasmic levels of polyols and an increase in levels of some amino acids, alanine, glutamic acid, glycine, proline, 5-oxoproline, serine and valine, which were significantly accumulated in the presence of SO_2. No alteration in the pentose phosphate pathway was observed, suggesting NADPH usage could be diverted to other pathways. Finally, a change in metabolites involved in the glycerophospholipid pathway (glycerol-3-phosphate and myo-inositol) was also found.