Biomass and Phenolic Acid Accumulation in Salvia austriaca Hairy Roots Grown in Temporary Immersion and Mist-Trickling Bioreactors

Transformed roots of Salvia austriaca were cultivated for 45 days in various systems, including Erlenmeyer flasks, a temporary immersion system (TIS) bioreactor, and a mist-trickling bioreactor, under controlled light conditions. The mist-trickling bioreactor yielded the highest biomass, with fresh and dry weights of 155.4 g/L and 10.2 g/L, respectively. Quantitative UHPLC analysis of hydromethanolic extracts revealed the biosynthesis of significant phenolic acids: caffeic acid, rosmarinic acid, and salvianolic acid A. Among these, rosmarinic acid was the most abundant, with its concentration varying based on the cultivation system. The highest total phenolic acid content, 165 mg/L, was obtained in the mist-trickling bioreactor, demonstrating its superiority in both biomass production and phenolic acid biosynthesis. This study highlights the potential of mist-trickling bioreactors for optimizing growth and metabolite production in S. austriaca transformed root cultures.