## 3 Results and Discussion
### Identification of Polyphenolic Compounds in Hydromethanonic Extract of Salvia austriaca Haity Roots
The Plantform bioreactor resulted in the lowest biomass yield, with 2.9 g and 45.9 g per liter of culture of the dry and fresh weight, respectively. Roots grown in the Plantform bioreactor exhibited larger darkening zones, indicating less favorable growth conditions (Figure 4). The highest growth index (Gi) value, based on fresh biomass, was observed for roots cultivated in flasks. In comparison, a lower Gi was recorded for roots grown in the mist-trickling bioreactor. The lowest Gi value (Gi = 3.25) was noted for roots cultivated in the Plantform bioreactor. This system also exhibited a relatively large dark zone, potentially indicative of root necrosis (Figure 4). The UHPLC chromatograms of the hydromethanolic extract confirmed the biosynthesis of the identified phenolic acids in all culture systems (Figure 6). Table 3 shows the _S. austriaca_ hairy root yield of phenolic acids after a 45-day growth period. The mist-trickling bioreactor exhibited the highest total phenolic acid biosynthesis, yielding 165 mg per liter of culture after 45 days. In contrast, roots in the Plantform bioreactor produced six times fewer phenolic acids (27 mg/L), while those in flasks yielded only 8 mg/L. Although the growth index (Gi) was significantly lower for roots in the mist-trickling bioreactor compared to flask cultures, the nebulized delivery of the liquid culture medium and the distinct growth conditions within the mist-trickling system greatly enhanced phenolic acid biosynthesis. Figure 5: Forty-five-day-old _S. austriaca_ transformed roots grown in mist-trickling bioreactor (bar 1 cm). The Kruskal-Wallis test revealed significant differences between the medians of phenolic acid content across different growth models (F--flask, Ptf--Plantform bioreactor, M-t--mist-trickling bioreactor)--with a \(p\)-value < 0.0001 for each phenolic acid measured in all cultivation environments. The Bonferroni procedure further indicated that there were statistically significant differences in the concentrations of all analyzed phenolic acids between culture models, as illustrated in Figure 7.  
Rosmarinic acid was the predominant metabolite, accounting for approximately 54% of the total phenolic acids in flask-grown roots and 93% and 96% in the Plantform and mist-trickling bioreactors, respectively. Caffeic acid was the least abundant, with 22%, 1.73%, and 1.43% synthesized in flask, Plantform, and mist-trickling systems, respectively. In conclusion, the mist-trickling bioreactor proves to be the most effective cultivation system for _S. austriaca_ hairy roots, delivering both high biomass yield and efficient phenolic acid biosynthesis. The system presented in this study is structurally simple, making it cost-effective and easy to operate. By dispersing the culture medium as a fine mist, the system reduces shear forces, which are less harmful to root growth compared to other methods [10; 21]. This makes it a promising option not only for laboratory research but also for a wide range of applications. While temporary immersion systems (TIS) like the Plantform bioreactor have been successful for some species [22], they may not be optimal for _S. austriaca_ and other plant species [23], as indicated by unfavorable morphological changes and lower metabolite yields. This suggests that, for each in vitro plant culture, the selection of a bioreactor for scaling up must be carefully evaluated and preceded by a thorough experimental investigation. Future research should further investigate the impact of light quality and other environmental factors on the growth and secondary metabolism of _S. austriaca_ hairy roots. Figure 6: The UHPLC chromatograms of the standard compound mixture (**A**) and the hydromethano-lic extract from _S. austriaca_ hairy roots (**B**). **Author Contributions:** Conceptualization, writing--review and editing, and methodology, L.K. ; methodology, investigation, A.K.K. ; data curation and visualization, I.P. ; conceptualization, D.M. ; methodology and formal analysis, J.P.; writing--review and editing, J.N.