Selection and characterization of Oenococcus oeni strains for use as new malolactic fermentation starter cultures

Abstract

Oenococcus oeni (O. oeni) strains are critically important for winemaking. They bring microbial stabilization, deacidification and sensory improvement through malolactic fermentation (MLF) to almost all red wines and some white wines. In this study, 23 strains of O. oeni isolated from China were evaluated for use as MLF starter cultures. Strains were characterized and screened in wine-like media with increasing selective pressure, such as low pH and high ethanol concentration. Their abilities to conduct MLF were affected significantly by ethanol concentration and pH. Eight strains were selected and subsequently evaluated by detecting the enzyme-encoding genes involved in biogenic amines synthesis and wine aroma modification. Seven well-performing strains were further assessed in newly alcohol-fermented Cabernet Sauvignon wine. The results show that strains O. oeni CS-4b and O. oeni ME-5b exhibited better performance than the commercial starter O. oeni 31MBR in wine. Therefore, they were selected as potential MLF starters suitable for wine with high ethanol concentration and low pH.

Impact of different temperature profiles on simultaneous yeast and bacteria fermentation

“…This process is necessary for lactic bacteria (belonging to the genera Oenococcus sp., Pediococcus sp., and Lactobacillus sp.) to obtain energy in wine, a harsh environment having generally lack of sugars (Battermann and Radler 1991;Wang et al 2016). The substitution of L-malic acid with L-lactic acid gives a more pleasant palate to wine, reducing its harshness.…”