EN
Hairy roots, characterized by rapid and stable growth, can be considered as a source of natural plant?s metabolites. The commercial utilization of roots is limited because of the difficulties during the culture in scaling up and designing of bioreactors, which could meet the requirements of optimal conditions of culture. The transformed root cultures of Paulownia tomentosa were conducted in shaking flasks of 300 cm3 containing 80 cm3 hormone-free WP medium, with 3% of sucrose. A mist bioreactor was also designed for transformed roots? cultures. Its glass prototype of 5 dm3 volume was used for optimization of hairy roots of Paulownia tomentosa. In the bioreactor containing 1 dm3 of the medium, after 28 days the dry mass harvest was 10.5-20.5 g depending on culture variants. The total amount of the main metabolite ? verbascoside in these roots was 8601170 mg in one culture (5672 mg/g of dry mass). The research performed on the prototype bioreactor enabled the optimization of its construction. It resulted in a new laboratory bioreactor of 10 dm3 volume made of glass and stainless steel.