Bioreactor Culture And Hypericin Accumulation Of Adventitious Roots In Hypericum Perforatum

Hypericum perforatum L. is the type species of Hypericum, and has a variety of pharmacological effects and a very high medicinal value. However in recent years, the wild resources of H. perforatum is severely depleted, furthermore the artificial cultivation of H. perforatum also faces the problem that the production and the content of effective components are unstable. This phenomenon hinders the development and utilization of resources. Therefore, in order to establish bioreactor culture system of adventitious root (AR) growth and hypricin accumulation in H. perforatum, further lay the foundation for the mass production of hypericin, and provide a technical reference and a new production methods of raw materials for products and large-scale production of H. perforatum, we used the sterile seedling leaves of H. perforatum to induce AR and selected suitable culture medium and conditions of bioreactor culture for AR.To optimize bioreactor culture system of adventitious root (AR) growth and hypricin accumulation, air volume, inoculation density, sugar types and concentrations, MS concentrations, IBA concentrations, pH and NH4+/NO3-ratio in culture medium were investigated. The results showed that an air volume of0.1vvm were bubbled into5L air-lift bioreactor with4L medium,5.0g·L-1(FW) of AR were inoculated in1.0MS medium supplied with40g·L-1white sugar,1.25mg-L"1IBA, pH5.8and NH4+/NO3-ratio in culture medium was adjusted to30/30mM, both AR biomass and hypericin accumulation were promoted under these culture conditions, hypericin content and productivity also reached to the maximum, the values were0.88mg·g-1and11.14mg-L"1, respectively.Then AR biomass, hypericin accumulation and medium dynamics changes of bioreactor culture were also researched, the results revealed that the biomass (fresh and dry weight) of AR increased with increasing culture days, AR grew slowly during the initial10d of culture, a linear phase was occurred from10to30d, followed by a slow growth phase from30to40d, and then a senescence phase thereafter; While hypericin production were still kept increasing from the initial culture, and the highest hypericin content (1.05mg·g-1) and productivity (15.65mg·L-1) of AR were observed on40d of culture. So40d of bioreactor culture was suggested as the best harvest date of AR. Specific oxygen uptake rate (SOUR) of AR sharply increased until10d of culture, and reached to the maximum0.27mmol·g-1·h-1on the10th d, dropped rapidly from10to25d, then gradually decreased from25to50d, finally down to minimum0.04mmol·g-1·h-1; However electrical conductivity (EC) showed little changes until10th d, dropped rapidly from10to25d, then declined slowly after25d of culture, the minimum was0.63ms·cm-1; dry weight increased as EC level decreased, there was a linear relationship between EC in culture medium and dry weight of AR. Furthermore, we found that it was suitable for AR growth with a slow upward trend of the pH in culture medium.The hypericin contents in40-d-bioreactor-grown adventitious roots were compared with that in40-d-in vitro plantlets and1-year-old plants, the hypericin content of adventitious roots reached1.05mg·g-1, which was higher than that of in vitro plantlets (0.15mg·g-1) and1-year-old plants (0.27mg·g’1). Hence, the bioreactor culture of adventitious roots is effective for the mass hypercin production of Hypericum perforatum in a short period.