SCAN: Selection of autochthonous Oenococcus oeni strains to be used as malolactic starters in the wine industry

SCAN Seminar

Title: Selection of autochthonous Oenococcus oeni strains to be used as malolactic starters in the wine industry

Speaker: Ana Paula Marques

Laboratory: Physiology of Environmentally Conditioned Microbiota

Abstract
Malolactic fermentation (MLF) is one of the most difficult steps to control in winemaking. MLF, especially important for high acidic wines, decreases its total acidity, improves microbiological stability and enhances organoleptic properties. Oenococcus oeni is the lactic acid bacteria mainly responsible by MLF. This species is normally well adapted to the harsh environment conditions of wine.
Relying on the indigenous bacteria to complete a timely and desirable MLF can be uncertain. When desirable malolactic acid bacteria are establish in a winery, the onset of the MLF may take several months and may occur in some barrels and tanks but not in others, depending on external factors (e.g. temperature and natural inoculum’s charge). For this reason, the use of selected O. oeni starter cultures became an option to accomplish wine MLF.
The selection of O. oeni strains having the most appropriate features is a multifaceted and challenging task. The main objective of this study was the selection of Portuguese autochthonous O. oeni strains to be used as MLF starters in the wine industry as an alternative to the existing universal commercial starters. They may have high malolactic and -glucosidase enzymes activity, lack of capacity to produce biogenic amines and ethyl carbamate precursors and to comprise suitable growth potential under different media environmental conditions, aiming the attainment of a high quality and safe product. Moreover the study of O. oeni genes transcriptional profile under different media environmental conditions was performed in order to better understand their influence on the genes expression in wine. This work allowed the selection of the most suitable O. oeni strains from different viticulture region of Portugal. The selected O. oeni strains behaviour will be evaluated in wine cellar-scale.

Short CV
July 2001 – Degree in Biotechnology by the Instituto Piaget;
September 2001 to September 2004 – Graduate Research Student at ITQB/IBET – UNL, in the Microbiology Laboratory;
October 2004 to September 2008 – PhD Student at ITQB/IBET-UNL, in the Physiology of Environmentally Conditioned Microbiota Laboratory and Microbiology and Biotechnology Laboratory from BioFIG-FC-UL, under the supervision of Dr. Vitória San Romão and Prof. Rogério Tenreiro (BioFIG-FC-UL).