## 5 Conclusions--Featured Applications  
The fermentation process was meticulously monitored utilizing the reversed-flow gas chromatography technique, enabling the assessment of different yeast strains' proficiency in fermenting fig syrup. Beyond physicochemical quantities related to alcohol production, this technique facilitated the estimation of various phases within the yeast life cycle. Although conventional gas chromatography with a flame ionization detector or mass spectrometry detection has been widely employed for quantifying ethanol concentration and by-products in fermentation processes, reversed-flow gas chromatography emerges as a viable alternative. Reversed-flow gas chromatography proves effective not only in determining ethanol concentration but also in assessing physicochemical parameters associated with the kinetics of each phase in alcoholic fermentation. This suggests that the application of reversed-flow gas chromatography allows for a more in-depth analysis, possibly capturing nuances and details that go beyond traditional concentration measurements. The information gathered through reversed-flow gas chromatography appears to be particularly relevant for assessing the efficiency of fermentation, especially in the context of genetically modified yeast strains. Regarding the substitution of a serine residue with alanine at position 533 (strain W_M4_533), it is suggested that this particular serine residue potentially inhibits the fermentation ability of _S. cerevisiae_ at various temperatures. Interestingly, this substitution conferred an enhanced fermentation ability at lower temperatures, significantly reducing the total fermentation time without compromising alcohol synthesis efficiency. The Ser558 Ala substitution (strain W_M4_558) also contributed to a reduced fermentation time, albeit to a lesser extent, gaining efficiency in the latter half of the fermentation process. In order to confirm the observed behaviors and draw robust conclusions about the effects of genetic modifications on fermentation efficiency, it would be advisable to conduct fermentations in various fermentation media. An in-depth kinetic analysis of each fermentation phase revealed that the W_M4_533 strain exhibited superior performance during the lag and log phases at lower temperatures, indicative of a psychrophilic phenotype. Conversely, the W_M4_558 strain demonstrated enhanced fermentation efficiency during the stationary phase at lower temperatures, hinting at a potential ethanol-resistant phenotype. The present investigation affirmed the efficacy of reversed-flow gas chromatography as a method for analyzing the kinetic aspects of alcoholic fermentation. Furthermore, it demonstrated that genetic modifications can yield strains capable of completing fermentation in reduced durations and/or at diminished temperatures. This finding holds significant implications for both ethanol-producing facilities and establishments engaged in the production of alcoholic beverages. Assessing the impact of genetically modified yeasts on the quality characteristics of the produced beverages requires a comprehensive analysis that goes beyond concentration measurements and fermentation efficiency. To draw meaningful conclusions, parameters such as aroma and taste profile, by-product production, consistency and reproducibility, microbial stability, etc., should be determined, in order for the final product to meet the regulatory standards for alcoholic beverages. Conceptualization, A.K. ; methodology, A.K. and D.S. ; software, K.K. and D.S. ; validation, A.K. and D.S. ; formal analysis, K.K. and D.S. ; investigation, K.K. ; resources, A.K. ; data curation, A.K. ; writing--original draft preparation, K.K. and D.S. ; writing--review and editingA.K. ; visualization, K.K., D.S. and A.K. ; supervision, A.K. ; project administration, A.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.