Microbial interactions in winemaking: Ecological aspects and effect on wine quality

Background: Wine microbiota is a dense and diverse ecosystem that is directly involved in the production and synthesis of many metabolites of oenological interest thereby directly affecting wine composition. The biodi- versity and successional evolution of yeast and lactic acid bacteria (LAB) species and strains within species during alcoholic (AF) and malolactic fermentation (MLF) is greatly influenced by the complexity of the wine environment. Consequently, the successful prediction of wine characteristics is limited. Scope and approach: The use of starter cultures has allowed better control of the fermentation process and the production of wines with desired characteristics. Mixed culture fermentations with selected non-Saccharomyces and Saccharomyces yeasts has regained attention in recent years due to their potential to modulate a wide range of metabolites of oenological interest. In this context, interactions among yeast species and LAB throughout the AF and MLF are known to influence the main enological parameters and aromatic profile of the wines. Studies have been conducted to uncover the nature of these interactions, with the aim to better control the AF and MLF. Key findings and conclusions: This review provides an overview of microorganism interactions during the different steps of the winemaking process. This gives wine producers the ability to control and fine-tune microorganism population dynamics and therefore the fermentation process and finally wine quality.