Biodiversity of Enological Lactic Acid Bacteria: Spe-cies- and Strain-dependent Plus/Minus Effects on Wine Quality and Safety

The winemaking results from several elaborate biochemical processes that see as protagonist either yeasts and lactic acid bacteria (LAB) of oenological interest. In particular, LAB have a fundamental role in determining the qual-ity chemical and aromatic properties of wine. They are essential not only for the malic acid conversion but also for the production of several desired by-products due to their important enzymatic activities that can release vol-atile aromatic compounds during malolactic fermentation (e.g. esters, car-bonyl compounds, thiols, monoterpenes). In addition, LAB in oenology can act as bio-protectors and reduce the content of undesired compounds. On the opposite, LAB can affect wine consumers' health as they can produce harmful compounds such as biogenic amines and ethyl carbamate under certain con-ditions during fermentation. Several of these positive and negative proper-ties are species- and strain-dependent characteristics. This review focuses on these aspects, summarising the current state of knowledge on the LAB's oe-nological diversity, highlighting their influence on the quality and safety of the final product. All reported information is of high interest to orient new selections, looking for new candidate strains to design starter cultures, mi-crobial resources for traditional/typical products, and green solutions in winemaking. In reason of the continuous interest in LAB as oenological bio-resources, we also underline the importance of inoculation timing. The considerable variability among LAB species/strains associated with sponta-neous consortia and the continuous advances in the characterisation of new species/strains of interest for applications in wine suggest that the exploita-tion of biodiversity belonging to this heterogeneous group of bacteria is still rising.