Active Compound Production Of Rhodiola Sachalinensis Using Airlift Bioreactors

Rhodiola sachalinensis A. Bor, widely used as a traditional Chinese medicine, is a perennial herbaceous plant and salidroside and polysaccharide are its important active compounds. In recent years, the wild resource of R. sachalinensis has been depleted and the problems such as lower or unstable active compound contents in cultivated plants and serious diseases existed during artificial cultivation. The shortage of plant materials has become one of the main barriers for production of R. sachalinensis products. Therefore, this study used air-lift bioreactor systems to investigate several factors affecting R. sachalinensis callus biomass and bioactive compound accumulation for producing salidroside or polysaccharide and further providing a new material in industrial production of R. sachalinensis products.To optimize the callus culture condition, factors affecting callus induction and proliferation were studied. The callus induction was favorable in MS medium supplemented with3mg·L-1BA and0.3mg-L-1NAA, induction rate reached62.2%. Callus proliferation was optimal when the ratio of NH4+/NO3" and PO43-concentration in MS medium were adjusted to30/30mM and1.25mM, respectively. During bioreactor culture,0.1vvm of aeration rate and12.5g-L-1of inoculation density promoted callus proliferation and salidroside or polysaccharide accumulation; Medium pH levels differently affected callus biomass and bioactive compound accumulation. pH5.8promoted callus proliferation, but pH4.8and pH7.8were benefit for improving salidroside and polysaccharide contents, respectively. However, the maximum yields of salidroside and polysaccharide were calculated at pH5.8. Methyl jasmonate (MeJA) was used as an elicitor to promote salidroside and polysaccharide accumulation. The maximum salidroside and polysaccharide productivities were found when initial culture medium was supplied with125and150μM MeJA;In two-step culture, MeJA was supplied to culture medium after20d of callus culture for various days, salidroside and polysaccharide accumulation were significantly enhanced by four-day treatment of225μM and275μM MeJA, respectively. During callus bioreactor culture, salidroside and polysaccharide productivities at the treatment of225μM MeJA were4.1-fold and1.7-fold more than the control group,44.1mg-L-1of salidroside and4.51g·L-1of polysaccharides were produced.Active compound contents in calluses were compared with plant shoots and roots. Salidrodside content in calluses was2.4-fold more than in plant shoots and similar to plant roots; polysaccharide content in callus was8-fold more than in plant shoots and3.6-fold in plant roots. Therefore, callus culture using bioreactor systems is an efficient method for mass production of bioactive compounds in R. sachalinensis, and has an important value for protecting and exploiting R. sachalinensis resource.