Cultivation Of Adventitious Roots Of Salvia Miltiorrhiza Using Bubble Bioreactors

Considering the advantages of hair roots culture, such as hormone-free, genetic stability, high productivity, it is suited for the plant tissue culture, which secondary metabolites mostly come from the root of plants. And sufficienct knowledge, such as rehologic behaviour, shear and mass tansfer in bioreactors, is important for large scale plant tissue clitivation.A group of bubble bioreactors were made to cultivate adventitious roots of Salvia miltiorrhiza, which was based on our preceding research work about different bubble bioreactors. The flow characteristics such as gas holdup (εg), liquid velocity and volumetric mass transfer coefficient (kLa) about the bubble bioreactor were investigated by multiphase flow and mass transfer measurement techniques. The culture conditions about the adventitious roots in the bubble bioreactor were also studied in our research work.The average gas holdup about the bioreactor was measured by liquid-overflow method and the volumetric mass transfer coefficient was measured by oxidation of sodium sulfite in the aqueous phase. The laser Doppler anemometer (LDA) was used to measure the liquid velocity in the bioreactor. The measurement results showed that gas holdup and kLa increased with the increasing of the air flow rate, and kLa reduced as the liquid volume of the bioreactor enhanced. The radial distribution of mean liquid velocity in the bioreactor was symmetrical, and the liquid velocitiy was influenced by air flow rate and axial distance from the distributor. At the axial distribution of the liquid velocity , the difference of the velocity become small with the decreasing of apparent air flow. As the mixing between bubbles and liquid, circumfluence occurred closed to the wall of the bioreactor. The velocity of the inverse flow was increased as the air flow rate increased.In the bubble bioreactors cultivation, the adventitious roots growth curve was S-shaped: Lag phase was during 0 and 15th d; Logarithmic phase was during 15th and 45th day; and stationary phase was during 45th and 55th day. The maximum biomass was obtained at 45th day, and fresh weight, dry weight and growth rate were 21.51±0.02g, 1.55±0.02g and 1.15±0.01, respectively. After 50 days cultivation, the content of tanshinonⅡA of the adventitious roots was 0.141±0.001 mg/g and the one of protocatechuic aldehyde was 0.131±0.001 mg/g. The adventitious roots were cultivated in bioreactors at different air flow rate, and the result illustrated that the adventitious roots grew better at 0.2L/min air flow rate than the others. And at that rate, the fresh weight, dry weight and increment were 24.50±0.01g,1.99±0.01g, and 1.58±0.02, respectively. The content of tanshinonⅡA of the adventitious roots was 0.131±0.001 mg/g and the content of protocatechuic aldehyde was 0.092±0.006 mg/g...