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Perez-Martin F.,University of Castilla - La Mancha | Sesena S.,University of Castilla - La Mancha | Izquierdo P.M.,Institute of Vine and Wine of Castilla La Mancha | Palop M.L.,University of Castilla - La Mancha
International Journal of Food Microbiology | Year: 2013

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. © 2013 Elsevier B.V. Source


Perez-Martin F.,University of Castilla - La Mancha | Sesena S.,University of Castilla - La Mancha | Izquierdo P.M.,Institute of Vine and Wine of Castilla La Mancha | Martin R.,University of Castilla - La Mancha | Palop M.L.,University of Castilla - La Mancha
World Journal of Microbiology and Biotechnology | Year: 2012

The aim of this study was to evaluate the ability from a number of lactic acid bacteria isolated from different sources to produce glycosidase enzymes. Representative isolates (225) from clusters obtained after genotyping, using randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis, of 1,464 isolates, were screened for β-D-glucosidase activity. Thirty-five of them were selected for subsequent analysis. These strains were able to hydrolyze α-D-glucopyranoside, β-D-xylopyranoside and α-L-arabinofuranoside although β-D-glucosidase activity was the predominant activity for 22 of the selected strains. Only some of them did so with α-L-rhamnopyranoside. All of these were from wine samples and were identified as belonging to the Oenococcus oeni species using Amplification and Restriction Analysis of 16S-rRNA gene (16S-ARDRA). When the influence of pH, temperature and ethanol or sugars content on β-D-glucosidase activity was assayed, a strain-dependent response was observed. The β-D-glucosidase activity occurred in both whole and sonicated cells but not in the supernatants from cultures or obtained after cell sonication. Strains 10, 17, 21, and 23 retained the most β-D-glucosidase activity when they were assayed at the conditions of temperature, pH, ethanol and sugar content used in winemaking. These results suggest that these strains could be used as a source of glycosidase enzymes for use in winemaking. © 2011 Springer Science+Business Media B.V. Source


Perez-Martin F.,University of Castilla - La Mancha | Sesena S.,University of Castilla - La Mancha | Izquierdo P.M.,Institute of Vine and Wine of Castilla La Mancha | Palop M.L.,University of Castilla - La Mancha
Food Microbiology | Year: 2014

The aim of this study was the genetic characterisation and safety evaluation of 129 Enterococcus isolates obtained from wine undergoing malolactic fermentation. Genetic characterisation by randomly amplified polymorphic DNA-PCR displayed 23 genotypes. 25 isolates representative of all genotypes were identified as Enterococcus faecium by species-specific PCR and assayed for antibiotic resistance, presence of virulence genes and aminobiogenic capacity, both in decarboxylase medium and wine. The aminobiogenic capacity in wine was analysed in presence (assay 1) and absence (assay 2) of Oenococcus oeni CECT 7621. Resistance to tetracycline, cotrimoxazol, vancomycin and teicoplanin was exhibited by 96% of the strains, but none of them harboured the assayed virulence genes. All of the strains harboured the tyrosine decarboxylase (tdc) gene, while 44% were positive for tyramine in decarboxylase medium. Only five out of 25 strains survived in wine after seven days of incubation, and when concentrations of biogenic amines in wines were determined by HPLC, only those wines in which the five surviving strains occurred contained biogenic amines. Histamine, putrescine and cadaverine were detected in wines from both assays, although concentrations were higher in assay 2. Tyramine and phenylethylamine were detected only in absence of O. oeni. This research contributes for the knowledge of safety aspects of enterococci related to winemaking. © 2014 Elsevier Ltd. Source


Perez-Martin F.,University of Castilla - La Mancha | Izquierdo-Canas P.M.,Institute of Vine and Wine of Castilla La Mancha | Sesena S.,University of Castilla - La Mancha | Garcia-Romero E.,Institute of Vine and Wine of Castilla La Mancha | Palop M.L.,University of Castilla - La Mancha
European Food Research and Technology | Year: 2014

The changes produced at the volatile fraction of a Tempranillo wine added with a natural glycosidic extract and commercial esters by the action of inoculated Oenococcus oeni strains during malolactic fermentation were assessed. The glycosidic extract was obtained from must of Muscat grape variety, and strains used had been selected in a previous work by their glycosidase and esterase activities against synthetic substrates. Fermentation assays were maintained in incubation for 22 days; after that, wines were analysed for their chemical parameters and the volatile compounds. Significant differences in the concentration of some volatile compounds in wines obtained with the different strains were observed, which could affect the sensory characteristics of the wines. The assayed strains were able to release terpenes, norisoprenoids and C6 alcohols, and to hydrolyse esters such as butyl acetate and 2-phenylethyl acetate. These results revealed that strains presented both glycosidase and esterase activities although in a strain-dependent manner. Strains Da32 and Ab11 are good candidates to be used when floral wines are desired, while strain 93 is the best preserving the fruity aroma of wines. © 2014, Springer-Verlag Berlin Heidelberg. Source

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