Presence of Oenococcus oeni and other lactic acid bacteria in grapes and wines from Priorat (Catalonia, Spain)

Abstract Oenococcus oeni , the lactic acid bacterium (LAB) mainly responsible for malolactic fermentation, has been repeatedly isolated from wines, but hardly ever from grapes. In this study, a large survey of autochthonous LAB from the Catalan wine region of Priorat was made. A total of 761 LAB isolates, 254 from Grenache and Carignan grape berries and 507 from wines, were identified and typed. Around 70% of the isolates were O. oeni , mostly from wines, but remarkably, 53 of them were isolated from grapes. A minimum spanning tree of O. oeni strains constructed from the multilocus variable number tandem repeat analysis showed considerable phylogenetic diversity. Other non- Oenococcus species were also identified and typed, Lactobacillus plantarum being predominant in grapes. Other LAB isolates were Pediococcus pentosaceus , Fructobacillus tropaeoli , L. mali , L. lindneri and L. sanfranciscensis . High-throughput sequencing (HTS) analysis was also carried out with grape samples, and Oenococcus and Lactobacillus were detected in significant quantities, which corroborates the culturing results from the same samples.