Effect of pH and ethanol on Lactiplantibacillus plantarum in red must fermentation: potential use of wine lees
Wine is the result of the alcoholic fermentation (AF) of grape must. Besides AF, wine can also undergo the malolactic fermentation (MLF) driven out by lactic acid bacteria (LAB). Among LAB, Oenococcus oeni and Lactiplantibacillus plantarum are the dominant species in wine. Even if O. oeni is the most common LAB undergoing MLF in wine, due to its high tolerance to wine conditions, L. plantarum can be used to undergo MLF in must. The moderate tolerance of L. plantarum to low pH and ethanol, may compromise the fermentative process in harsh wines. Besides, the use of wine lees has been reported to stimulate MLF of O. oeni in wine . Altogether, the aim of this work was to evaluate the MLF performance of L. plantarum in red grape must at different pHs, ethanol concentrations, and in the presence or absence of wine lees.
The results showed that L. plantarum can perform MLF even at pH 2.5. However, in presence of 6% (vol/vol) of ethanol, which can correspond to an early AF stage, MLF failed below pH 3.25. This behavior was observed in two commercial strains. However, the presence of wine lees in grape must at pH 3.25 allowed the completion of MLF. The addition of wine lees to the preinoculum or to the grape must also enhanced bacterial survival. Indeed, the supplementation in the preinoculum allowed the depletion of L-malic acid with one strain. In summary, wine lees potentially increase the survival of L. plantarum in red grape must, and thus, enhance MLF performance.
Acknowledgements: this work was supported by grant PID2021-124943OB-I00 (Spanish Research Agency). Aitor Balmaseda is a Margarita Salas postdoc researcher (2021URVMS‐25, Spanish Ministry of Universities financed with European Union-NextGenerationEU).
1) Balmaseda A. et al. (2021). Simulated lees of different yeast species modify the performance of malolactic fermentation by Oenococcus oeni in wine-like medium. Food Microbiology, 99, 103839.
Issue: ICGWS 2023
1Universitat Rovira i Virgili, Departament de Bioquímica i Biotecnologia, Facultat d’Enologia, Grup de Biotecnologia Enològica, C/ Marcel⋅lí Domingo 1, 43007 Tarragona, Catalonia, Spain
2Universitat Rovira i Virgili, Departament de Bioquímica i Biotecnologia, Facultat d’Enologia, Grup de Biotecnologia Microbiana dels Aliments, C/ Marcel⋅lí Domingo 1, 43007 Tarragona, Catalonia, Spain