Grape Microbiome: Potential and Opportunities as a Source of Starter Cultures

Abstract

Grape microbiome is the source of a vastly diverse pool of filamentous fungi, yeast and bacteria that will play a coordinated role for the quality of the produced wines. In recent times, the significance of this pool of microorganisms with a long list of studies of the microbial ecology of grape berries of different geographical origin, cultural practices, grape varieties and climatic conditions has been acknowledged. Similarly, the ongoing microbial evolution of must fermentations has been fully uncovered. All these ecology studies, along with detailed metabolic studies and sensorial characterisations of the produced wines, led to the suggestion of the microbial terroir. These new concepts are today leading worldwide research efforts to the production of unique wines, preserving their historical identity and verifying their quality and geographical origin. This chapter is a quick but thorough and up-to-date review of how autochthonous microbiota highlight the terroir in wines, a comparison of commercial and wild yeast strains and how this biodiversity has been explored. Moreover, technological, physiological and oenological selection criteria will be under consideration. At the end, the positive and negative aspects of wild vinifications, the technological problems of wild strains and some suggestions for the future in starter cultures will be presented.

The Multiple and Versatile Roles of Aureobasidium pullulans in the Vitivinicultural Sector

“…On the contrary, A. pullulans was found at significant high levels at studies conducted in Italy [14], Spain [15], Canada [16], Australia [4] and South Africa [17], while it often was isolated from Brazil, France, New Zealand, Greece and Slovenia, [18][19][20][21][22] as reviewed by Bozoudi and Tsaltas [12].…”

“…It has been recorded that soil, grape variety and grape growing practices influence the microbial ecosystem [11][12][13]. Microbial species present on the surface of grape berries at harvest play an important role in winemaking, and thus, counting and identifying them is of great importance.…”

Modulating Wine Pleasantness Throughout Wine-Yeast Co-Inoculation or Sequential Inoculation

“…The wine industry attempts to diversify producing wines with distinctive characteristics and creating high-quality new products. A true test for winemakers is to blend several grapes, grown on different soil and climate conditions (terroir), with a developing science of yeast and bacterial metabolism, to produce the most enjoyable wine [52]. Many winemakers today use commercial yeast and bacteria starter cultures for alcoholic and malolactic fermentation, respectively.…”

Contribution of Yeast in Wine Aroma and Flavour

“…Torulaspora delbrueckii and Metschnikowia pulcherrima are enhancing a very good aromatic profile if used in combination with S. cerevisiae [52][53][54][55]. Efforts to further our knowledge on the related pathways [56] as well as better exploiting the capacity of mixed cultures (Saccharomyces with non-Saccharomyces) are copious [57][58][59][60][61][62].…”

“…In addition to the above, it is of current interest, research and development the role and use of other non-Saccharomyces yeasts from the native microbiota of grapes contributing to the complexity of wine aroma [59,60,[77][78][79] and the geographical fingerprinting and indication of origin [57,80,81]. With these latest developments, it is understandable that it is impossible to proceed without good understanding of the yeasts physiological traits of many more genus, species and strains along the environment's role on them.…”