# Effect of Ultrasound on Fermentation of Thick Molasses Worts by Distiller's Yeast
## 3 Results and Discussion
### Wort Analysis
#### 3.2.3 Influence of Ultrasound Treatment on Fermentation Dynamics
91-99% of the sample was fermented, depending on the strain used and the ultrasound treatment method. The sample fermented by ER yeast using ultrasound treatment at 50% amplitude throughout the process stands out. The values for this sample were significantly higher than for the ER control sample. A similar trend was observed for the TD yeast-fermented sample supported by analogous ultrasonic treatment, showing that the TD strain, compared to ER yeast, exhibited a much slower fermentation dynamic; however, at the end of 72 h of fermentation, the fermentation with these yeasts, regardless of the ultrasonic treatment method, also reached values above 91%. The percentage weight loss of the samples corresponds to the appropriate high results of sugar utilisation shown earlier for the word of 18 \({}^{\circ}\)Blg. The results for the first 48 h of fermentation of all samples indicate that ultrasonic treatment positively affected the fermentation dynamics of the samples. Increasing the ultrasound intensity from an amplitude of 50 to 75% of the maximum value improved the fermentation dynamics of the samples. In the case of word with an initial density of 22 \({}^{\circ}\)Blg (Figure 2), the positive effect of ultrasonic treatment is visible in the dynamics graph for both strains, including the final weight loss after 72 h of fermentation, with the maximum final values achieved for the ERus75 and TDus75 samples being 74.49% and 42.63% of theoretical fermentation, respectively. These results indicate that for the 22 \({}^{\circ}\)Blg word, the assumed fermentation time (72 h) was too short to achieve complete fermentation, which is confirmed by the data on the utilisation of sugars (in particular fructose) presented earlier. A similar trend, i.e., delays between the assimilation of sugars and the production of ethanol and carbon dioxide from them, is reported by [PERSON] et al. [63] during the fermentation of lignocellulosic hydrolysate by _S. cerevisiae_ yeast. Other researchers have also presented similar data [64; 65; 66]. The results of the fermentation dynamics of the sample with a density of 24 \({}^{\circ}\)Blg (Figure 3) show, similarly to the previously discussed results of sugar assimilation, that 72 h was too short a time for the sugars in the word to ferment, and the initial density of the wort itself significantly delayed the fermentation of the samples. The loss of word mass after the first 24 h of the process, regardless of the processing method and the strain used, did not exceed 6.38%. However, an apparent positive effect of ultrasonic treatment on the  
Figure 3: Percentage release of carbon dioxide during fermentation of 24 \({}^{\circ}\)Blg word depending on ultrasound treatment and yeast strain. loss of sample weight was observed. After 72 h of the process, the difference in the weight loss of the ultrasonicated sample with an amplitude of 75% and the control sample was about 20% for the Ethanol Red strain and about 10% for Thermosac Dry yeast. [PERSON] et al. [44] described thick sugar beet juice fermentation with fermentation dynamics similar to those we presented. As in our case, during the fermentation of thick wort in the first 24 h, the yeast adapted its metabolism to the thick wort without causing significant sample weight loss.