Effect Of Candida zemplinina oak chips biofilm on wine aroma profile

Introduction Candida zemplinina (synonym Starmerella bacillaris) is known to play relevant activities during winemaking, due to its fructophilic nature and low ethanol production rate (Masneuf-Pomarede et al., 2015). Moreover, wines fermented with C. zemplinina and S. cerevisiae showed higher amounts of glycerol and esters (Englezos et al., 2016; Tofalo et al., 2016). Saccharomyces and non-Saccharomyces yeasts’ formulations are available in different forms including the Cream Yeast (CRY) preparation, Active Dry Yeast (ADY), Active Frozen Yeast (AFY) (Fracassetti et al., 2020). In all these cases yeasts develop as planktonic cells. However, in nature microbes prefer a sessile lifestyle and are often organized in biofilms. Biofilms are structures made up of singleand multiplespecies attached on a biotic or an abiotic surface and embedded in a self-produced matrix (Lebleux et al., 2020). Sessile cells are more resistant to stressing conditions through metabolic cross-feeding, cell–cell interactions and especially chemical and physical resistance (Bastard et al., 2016). This growth strategy is exploited to improve some microbial activities, for instance it is used to increase ethanol production (Germec et al., 2016), and a recent study revealed that Oenococcus oeni cells organized in biofilms on oak showed a better malolactic activity, and improved the volatile composition of wines (Bastard et al., 2016). Despite the positive impact of C. zemplinina on wine characteristics the majority of studies are focused on planktonic cells. Therefore, in this study, 10 strains of C. zemplinina were tested for their ability to form biofilms on winemaking material such as stainless steel and oak chips. The impact of oak surfaceassociated C. zemplinina cells on fermentation kinetics and volatile profile was also evaluated.