It is well known that high ethanol levels in wines adversely affect the perception of new wine consumers. Moreover, numerous issues, such as civil restrictions, health risk and trade barriers, are associated with high ethanol concentrations. Several strategies have been proposed to produce wines with lower alcoholic content, one simple and inexpensive approach being the use of new wine native yeasts with less efficiency in sugar to ethanol conversion. Nevertheless, it is also necessary that these yeasts do not impair the quality of wine. In this work, we tested the effect of sequential culture between Hanseniaspora uvarum BHu9 and Saccharomyces cerevisiae BSc114 on ethanol production. Then, the wines produced were analyzed by GC-MS and tested by a sensorial panel. Co-culture had a positive impact on ethanol reduction and sensory profile when compared to the S. cerevisiae monoculture. Wines with lower alcohol content were related to fruity aroma; moreover, color intensity was associated. The wines obtained with S. cerevisiae BSc114 in pure conditions were described by parameters linked with high ethanol levels, such as hotness and astringency. Moreover, floral profile was related to this treatment. Based on these findings, this work provides a contribution to answer the current consumers’ preferences and addresses the main challenges faced by the enological industry.

Two major spoilage yeasts in the wine industry, Brettanomyces bruxellensis and Zygosaccharomyces rouxii, produce off-flavors and gas, causing considerable economic losses. Traditionally, SO₂ has been used in winemaking to prevent spoilage, but strict regulations are in place regarding its use due to its toxic and allergenic effects. To reduce its usage researchers have been searching for alternative techniques. One alternative is biocontrol, which can be used either independently or in a complementary way to chemical control (SO₂). The present study analyzed 122 native non-Saccharomyces yeasts for their biocontrol activity and their ability to be employed under fermentation conditions, as well as certain enological traits. After the native non-Saccharomyces yeasts were assayed for their biocontrol activity, 10 biocontroller yeasts were selected and assayed for their ability to prevail in the fermentation medium, as well as with respect to their corresponding positive/negative contribution to the wine. Two yeasts that satisfy these characteristics were Wickerhamomyces anomalus BWa156 and Metschnikowia pulcherrima BMp29, which were selected for further research in application to mixed fermentations.

Organic inputs constitute an alternative way to replace or reduce the use of agrochemicals in order to increase sustainability and reduce negative impacts of agriculture on the environment. A consistent determination of average yields obtained with organic fertilizers in comparison to synthetic fertilizers is necessary to assess their potential in both commercial and organic agriculture. To achieve this goal, a meta-analysis of existing scientific data of yields obtained with digestate or compost tea fertilization was performed. After a systematic bibliographic search of scientific publications, 35 final papers remained from >1000 initial results. Data of crop yield with digestate or compost tea fertilization, as well as control and synthetic fertilizer treatments, were extracted from the selected articles and used to calculate response ratios (ratios of means), obtaining 106 observations. The meta-analysis showed that digestate fertilization produced yields 80% higher than the control. Yields were statistically similar to those obtained with conventional treatments with chemical fertilization (only 2% lower in average). The results for digestate are considered robust as the significance did not change after conducting publication bias analyses. However, the high heterogeneity observed suggests the existence of explanatory variables accounting for part of the observed dispersion. Subgroup analyses were conducted to determine the variation of the results of digestate across crop species and field or greenhouse experiments, while compost teas did not present adequate data quantity to obtain reliable results. According to this meta-analysis, anaerobic digestate had an acceptable performance as fertilizer for several crops at a reported application rate ranging from 100 to 480 kg N ha⁻¹. Regarding compost tea, yields were 92% higher than the control and 10% lower than synthetic fertilization treatments, although more information is required to draw a conclusive result due to the low number of observations of this fertilizer. Further investigation is necessary to understand yield variations under different scenarios to study the influence of secondary variables and to propose management measures for producers.

The utilization of grape juice from low oenological value grape varieties for bioethanol production represent an alternative for diversification and value addition in viticulture. Optimizing Very High Gravity (VHG) fermentation can significantly increase ethanol productivity while reducing water and energy consumption. In this study, the impact of different nitrogen sources on growth and fermentative performance of locally selected yeast strains was investigated. Five yeast strains of species Saccharomyces cerevisiae and Zygosaccharomyces rouxii were cultured in both synthetic culture media and natural grape juice supplemented with ammonium sulfate (NH), yeast extract (YE), Fermaid K (FERM), and urea (U) at varying concentrations. Due to the very low fermentation rate, the Z. rouxii strain was excluded from the selection. The results obtained in synthetic medium showed that nitrogen sources that promoted growth (NH and YE) had minimal effects on fermentative performance and were highly dependent on the specific yeast strain. However, the combination of urea and ammonium favored the rate of sugar consumption. When validated in natural grape juice, urea combined with ammonium (U + NH 300 + 75 mg/L) improved both growth parameters and ethanol yield. Doubling the concentration (U + NH 600 + 150 mg/L) further enhanced sugar consumption and ethanol production while reducing unwanted by-products. The combined use of urea and ammonium exhibited a synergistic effect, making it a cost-effective nitrogen supplement for VHG fermentations.