INVESTIGADORES
MENDOZA Lucia Margarita
congresos y reuniones científicas
Título:
Molecular basis of Oenococcus oeni stress response to inhibitory compounds produced by wine yeasts during fermentation
Autor/es:
LUCÍA M. MENDOZA; SILVINA FADDA; GRACIELA VIGNOLO; RAÚL R. RAYA
Lugar:
Egmond aan Zee
Reunión:
Simposio; 11th Symposium on Lactic Acid Bacteria; 2014
Resumen:
Oenococcus oeni is the most important lactic
acid bacterium species involved in the induction of malolactic fermentation
(MLF) at the end of the alcoholic fermentation (AF) during wine-making process.
MLF is a critical step to obtain a high quality final product. However,
bacterial growth and MLF are not always successful due to the harsh
environmental conditions of wine. The viability of O. oeni in wine
depends on its resistance to several stress factors such as acidity, SO2,
ethanol and other inhibitory metabolites produced by wine yeasts. To study the
possible mechanisms that O. oeni X2L
utilizes to survive and carry out the MLF in stressful wine conditions, a
proteomic approach (2D-E) and RT-PCR were performed. O. oeni X2L was grown in unfermented (control) and
fermented grape juice. Forty three proteins spots showed significant changes in
expression during growth in fermented juice: 23 spots were up-regulated while
18 proteins down-regulated. One spot (aminotransferase/fructokinase) was
specific to fermented medium while another spot (aspartate
carbamoyltransferase) was completely inhibited in this condition. Enzymes
involved in carbohydrate, lipid, nucleotide and amino acids metabolism, as well
as chaperone proteins (DnaK/DnaJ) and two peptidases (oligopeptidase F and
endopeptidase O) were over-expressed while enzymes related to lipid
biosynthesis, glycolysis, amino acid metabolism, hydrolases and dehydrogenases
were down-regulated. Also, differential expression of genes involved in malic
acid and citrate metabolism was observed when O. oeni grew in fermented medium. This study contributes to the
knowledge of the molecular mechanisms used by O. oeni to tolerate stressful wine conditions as well as to the
selection of the best adapted starter culture to carry out successfully the MLF
during wine-making.