Mass Production of Transformed Hairy Root for Secondary Metabolites: A Case Study of Panax ginseng Hairy Roots

Abstract

Ginseng plant (Panax ginseng C.A. Meyer) is a famous oriental medicinal plant, and it has many bioactive compounds useful for human. In this work, we reorganized the published papers on the development of large-scale culture system and secondary metabolite production of transformed hairy roots induced from P. ginseng. Hairy roots showed an active branching and fast growth pattern in plant growth regulator-free medium. Hairy roots has a short lag period of 4 days, and then the exponential growth phase continued from 4 to 45 days in the shake flask cultures. During the exponential growth phase, secondary metabolites of hairy roots are lowly accumulated due to relation with non-growth-associated mechanism. To develop large-scale culture system, several kinds of bioreactor systems were applied to cultivate hairy roots. In 20 L air bubble bioreactor, hairy roots have grown 18-fold on a dry weight basis and growth rate of 0.34 day−1 with a 0.2% (w/v) inoculum during 36 days. The introduction of several elicitors stimulates the formation of secondary metabolites and can reduce the cultivation time. Overall, hairy root culture systems are useful and available to mass production of plant-derived products.