Use of Oenococcus oeni biofilm for wine malolactic fermentation management

Controlling the speed of malolactic fermentation in red wine is an important challenge to produce certain short-rotation wines, like primeur style wines, for entry-level market segments. This study shows the possibility of inducing the adhesion and biofilm formation of Oenococcus oeni Vitilactic F© and Saccharomyces cerevisiae 522D©, in a low-nutrient medium, on Nylon© carriers in a continuous flow 250 mL bioreactor. The biofilm formation medium was then replaced by fermentation media (grape must for co-alcoholic and malolactic fermentations with O. oeni and S. cerevisiae biofilms) or wine (with O. oeni biofilms only) and the progress of malolactic fermentation was monitored: over periods of three to four weeks under a continuous regime, stable conversion speeds for L-malic acid of 0.53 g/L/24 h (malolactic fermentation in wine medium) and of 2.04 g/L/24 h (co-fermentations fermenting grape must medium) are reached. O. oeni biofilms on Nylon© carriers were also transferred in wine for four successive batch fermentations: in these conditions, L-malic acid conversion speed was 0.35 g/L/24 h. These biofilm implementation systems could be the first step towards perfectly controlled industrial malolactic fermentation processes.