STUDY OF SURFACE DAMAGE ON CELL ENVELOPE ASSESED BY AFM AND FLOW CYTOMETRY OF LACTOBACILLUS PLANTARUM EXPOSED TO ETHANOL AND DEHYDRATION

BRAVO FERRADA, B; GONÇALVES, S; SEMORILE, L; SANTOS, NC; TYMCZYSZYN, EE; HOLLMANN, A

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2015 vol. 118 p. 1409 - 1417

1364-5072

Aims: In this work we evaluated freeze-drying damage at surface level of oenological strain Lactobacillus plantarum UNQLp155, as well as its ability to grow in a synthetic wine with and without pre-acclimation. Methods and Results: Damage on cell surface was studied by flow cytometry, Zeta potential and atomic force microscopy and cell survival was analyzed by plate count. Results showed that beside cells acclimated at lower ethanol concentration (6% v/v) became more susceptible to drying than non-acclimated ones, after rehydration maintain their increased ability to growth in a synthetic wine. Acclimation at a higher ethanol concentration (10% v/v) produces several damages on the cell surface losing its ability to grow in a synthetic wine. Conclusions: In this work we showed by first time that sub-lethal alterations on bacterial surface induced by a pre-acclimation with a low ethanol concentration (6%) , upon a freeze-drying process, result in a better bacterial adaptation to the stress conditions of wine-like medium, as well as to the preservation process. Significance and Impact of Study: Understanding the adaptation to ethanol of oenological strains to and their effects on the preservation process has a strong impact on winemaking process and allows to define the most appropriate conditions to obtain malolactic starters cultures.