3.4 N. atacamensis exhibits a potential utilization in wine fermentation.
To determine the potential of N. atacamensis for the elaboration of alcoholic beverages, we conducted initial evaluations of biomass production under microculture conditions utilizing the ATA-11A-BT strain as representative of the species. Various carbon sources and fermentation-related conditions, including glucose and fructose utilization, as well as ethanol and high glucose concentration tolerance, were examined, with the EC1118 wine S. cerevisiae strain used as a comparison. Overall, N. atacamensisATA-11A-BT showed lower growth rates (μmax) as compared to EC1118 when cultured with 2% glucose or 2% fructose (p -value < 0.05, one-way ANOVA, Figure 5A ,Table S7 ). When we evaluated growth under the sucrose disaccharide as a carbon source, we did not observe significant differences between the N. atacamensis and the S. cerevisiae strains, where ATA-11A-BT exhibited a lower µmax than the S. cerevisiae wine strain (p -value > 0.05, one-way ANOVA, Figure 5A ).
Subsequently, we subjected ATA-11A-BT to ethanol and high glucose concentrations as stressors. ATA-11A-BTdisplayed a high tolerance to ethanol, as it was able to grow in the presence of ethanol up to 8% v/v (Figure 5B ). However, the growth rates of ATA-11A-BT under ethanol conditions were still lower compared to those of EC1118 (p -value < 0.05, one-way ANOVA). Despite this difference, the observed ethanol tolerance of ATA-11A-BT highlights its potential for fermentation processes. Furthermore, the N. atacamensis strain exhibited a high μmax when cultured in 20% glucose, indicating its potential suitability for wine fermentation conditions. In this sense, other species from the same genus, such as N. ishiwadae have been previously reported to possess high ethanol tolerance and show potential for oenological applications (Ruiz et al. , 2019, van Wyk et al. , 2020).