| Rhodiola sachalinensis, a treasure traditional medicinal plant in Chang bai mountain area, has higher medicinal values, however, the raw materials of R. sachalinensis for its product production is deficiency due to the shortage of wild resource and the problems of artificial cultivation. Therefore, the cells cultured by using the method of plant cell culture as a new material source has an important meaning. In the present study,3 L balloon type airlift bioreactors were used to investigate the effects of several factors affecting biomass and bioactive compound accumulation for optimization of bioreactor callus culture system; meanwhile, the elicitors were used to enhance the bioactive compound accumulation. The present study will provide a theoretical reason for further commercial production of R. Sachalinensis products.The sparger size significantly affected callus growth and bioactive compound accumulation. Compared with different diameter of the spargers,3.5 cm diameter of sparger was favorable for callus biomass and bioactive compound accumulation, therefore, the sparger in a bioreactor should be designed to 3.5 cm diameterfor callus culture of R. sachalinensis. During callus bioreactor culture, the light intensity influenced callus growth and bioactive compound synthesis,30 μmol cm-2s-1 of light intensity was suitable. The culture medium was critically important, the callus growth was optimum at MS 1×, but the different kind of bioactive compound accumulation varied among the MS medium strengths, the maximum synthesis of phenolic at MS 1/2×, flavonoid and polysaccharide at MS lx, and salidroside at MS 3/2x. Sucrose concentration in culture medium also had an important influence, the maximum callus biomass and the accumulation of salidroside, phenolics and flavonoids was found at 30 g L-1 of sucrose but polysaccharides at 50 g L-1 of sucrose. The study of callus growth kinetics indicated that callus growth could be divided to 4 phases including lag phase from initial to 10 d, exponential phase from 10 to 20 d, the stationary phase from 20 to 25 d, and the decrepitude phase from 25 d to 30 d. In addition, the maximum salidroside or phenolics were found at 20 d and polysaccharide or flavonoid at 25 d.For enhancing bioactive compound accumulation, Methyl jasmonate (MeJA) and salicylic acid (SA) were used as elicitors to treat calluses after 20 d of bioreactor culture and found that the optimal treatment days was 3 d. The suitable SA concentration was different according to the kind of bioactive compounds, the maximum salidroside or polysaccharides was found at the treatment of 100 μmol SA and phenolic or flavonoids at the treatment of 150 μmol SA. However,275 μmol MeJA was optimal for all bioactive compound (salidroside, phenolic, and flavonoid) production. Finally, the present study investigated the antioxidant activity of bioreactor culture-calluses. The higher antioxidant activity was found in the calluses treated with MeJA when compared with the calluses which were unteated with MeJA.Consequently, callus bioreactor culture for producing bioactive compounds of R. sachalinensis could provide mass calluses to the product production of R. sachalinensis as an alternative materials, this approach has an important meaning for satisfying a market need. |
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