Genetic screening of wine-related enzymes in Lactobacillus species isolated from South African wines

Aims: The objective of this study was to investigate the presence of genes coding for enzymes of oenological relevance in wine Lactobacillus strains isolated from South African grape and wine samples during the 2001 and 2002 harvest seasons. Methods and Results: A total of 120 wine lactobacilli isolates belonging to Lactobacillus plantarum, Lactobacillus hilgardii, Lactobacillus brevis, Lactobacillus pentosus, Lactobacillus paracasei, Lactobacillus sakei and Lactobacillus paraplantarum were genetically screened for enzyme-encoding genes using PCR with primers specific for beta-glucosidase, protease, esterase, citrate lyase and phenolic acid decarboxylase. The results of PCR screening showed that the Lactobacillus strains possessed different combinations of enzymes and that some strains did not possess any of the enzymes tested. Confirmation analysis with gene sequencing also showed high similarity of genes with those available in GenBank database. Conclusion: In this study, we have demonstrated the existence of genes coding for wine-related enzymes in wine lactobacilli that could potentially hydrolyse wine precursors to positively influence wine aroma. Significance and Impact of the Study: An expansion of knowledge on the genetic diversity of wine-associated lactic acid bacteria will enable the selection of novel malolactic fermentation starter cultures with desired oenological traits for the improvement of the organoleptic quality of the wine, and hence wine aroma.