Molecular and technological characterization of indigenous Oenococcus oeni strains in Negro amaro, typical Salento wine (Apulia, Italy), produced in two different areas.

The purpose of this study was to perform the molecular and technological characterization of indigenous strains of Oenococcus oeni, with excellent winemaking skills, isolated from wines produced by grapes of two different Salento areas (Apulia, Italy), in order to select strains from using as a malolactic fermentation (MLF) starter in wine. Sequences discriminating the different species were obtained by species-specific PCR with primers specific for the MLE gene and subsequent sequence analysis of PCR products on RNA containing the region for the 16S gene. In this way were identified as O. oeni, 75 lactic acid bacteria from a total of 210, isolated from Negro amaro wine (Salice Salentino area) and 80 from a total of 220 lactic acid bacteria, isolated from Negro amaro wine (Guagnano area), during malolactic fermentation. Genotypic analysis was performed by molecular technique (AFLP) based on amplified fragment length polymorphism, in order to develop molecular profiles that differentiate and characterize several O. oeni strains. To design specific bacterial strains for the different characteristics of a wine, it is necessary to consider various criteria as resistance to ethanol, SO2, growth at low pH, assessment of the malate metabolism and absence of negative traits to the health of consumers (biogenic amines [BA], ethyl carbamate). These selection criteria were applied to several strains (chosen from different subgroups of the cluster obtained by AFLP). The results allowed to select some of these strains that may have a good fermentation performance.