Technological potential of the Oenococcus oeni UNQOe19 indigenous strain for use as a malolactic fermentation starter

Abstract

During winemaking, lactic acid bacteria (LAB) conduct malolactic fermentation (MLF), reducing total acidity, and influencing the wine's aromatic profile. In Argentina, imported starter cultures containing strains from other world regions are used to drive MLF. Therefore, developing malolactic starters with native strains selected for their oenological potential presents a significant opportunity for the wine sector and regional economies.
These starters must have the technological properties necessary to survive the challenging conditions of winemaking and should be available in a dehydrated format to ensure easy preservation and marketing. To produce starter cultures on a large scale, it is essential to optimize the growth of native LAB biomass. Utilizing byproducts from the food industry to create alternative culture media could replace commercial ones, allowing for the sustainable production of native starters. This innovation would enhance the regional character of wines while preserving the distinctive qualities of the terroir.
This study aimed, first, to optimize the biomass production of the Oenococcus oeni strain UNQOe19 in alternative culture media made from food industry byproducts, such as apple pomace and whey permeate. Second, it evaluated the technological properties of the O. oeni strain UNQOe19 by assessing its tolerance to varying levels of pH, alcohol, sulfites, lysozyme, and freeze-drying conditions. The UNQOe19 strain grew on both alternative substrates supplemented with yeast extract and salts. Furthermore, it exhibited tolerance to sulfites (SO2), acidic pH, and 10% ethanol, while maintaining viability during the freeze-drying process. This, makes it suitable for presentation as a solid-form malolactic starter.