Esterase activity of lactic acid bacteria isolated from malolactic fermentation of red wines

The goal of this study was to examine the esterase activity of 243 lactic acid bacteria (LAB) strains from wines of different red grape varieties, belonging to the genera Oenococcus, Lactobacillus, Pediococcus and Enterococcus. p-Nitrophenyl octanoate was used as substrate. All strains presented esterase activity in the first screening, but only those showing higher activity were used in subsequent studies to determine the cellular location of this activity, the influence of pH, temperature and the presence of ethanol and the substrate specificity. For the thirteen selected strains, the highest activity was observed in the intracellular fraction. Responses to pH, temperature and ethanol were strain-dependent, but for all the strains, a marked decrease in activity in presence of ethanol was observed. When the influence of pH and ethanol acting together was studied at 25 °C and 37 °C, temperature-dependent differences were not observed for any of the strains except for Oen6. In the substrate specificity assay, the majority of strains of all genera displayed a trend to more readily hydrolyse ester substrates from C8 and longer.