Background: Plants are a source of a variety of secondary metabolites. Agrobacterium rhizogenes mediated
hairy root cultures offer a great advantage for the production of these metabolites in large
amounts in comparison to cell suspension cultures as they have the capability of fast growth along with
genetic stability. In order to commercialise secondary metabolite production, the mass production of
hairy root cultures is of paramount importance. Various conventional bioreactors, broadly classified as
liquid phase and gas phase reactors, have been employed for this purpose which includes airlift, bubble
column, stirred tank, trickle bed, nutrient mist, spray reactors and others.
Objective: This review discussed various aspects of hairy root culture in bioreactors.
Method: Peer-reviewed research literature was searched and screened for information about the evolution
of designs of bioreactors used for hairy roots culture. Data was gathered after a keen search from
research and review articles and is presented in this review paper.
Results: The major limitations of the conventional type bioreactor systems were high shear stress and
oxygen deficiency, thus the demand for improved designs led to the evolution and designing of various
types of bioreactor systems with low shear stress and better oxygen uptake in order to enhance yield
productivity. Amidst these modifications in reactors, hybrid reactors, which are a combination of liquid
phase and gas phase reactors, offer a very promising approach for commercialisation of secondary metabolite
production using hairy root cultures.
Conclusion: Although many efforts have been done to obtain a bioreactor configuration for highest
biomass possible, there are still chances of improvement to get the most suitable bioreactor that could
provide high oxygen mass transfer, better growth characteristics, homogenous culture environment and
minimum shear stress.