Table 1.

Micropropagation of plants via organogenesis and somatic embryogenesis: Merits and demerits of bioreactor configurations.

Bioreactor configurations	Merits	Demerits	References
Liquid-phase bioreactors
Stirred tank bioreactor	-Effective fluid blending. -Substantial oxygen mass transfer. -It is simple to regulate the pH, temperature, dissolved oxygen, and nutrient concentration. -Scaling up is simple. -Alternatives to impellers are offered. -Very flexible in terms of product and manufacturing size.	-As a result of mechanical agitation, high energy costs. -Shear stress on the organs or cells in culture. -Difficulties with biomass harvesting and inoculation -High likelihood of contamination. -Labor-intensive for maintenance, cleaning, and restart.	Georgiev (2014); Mamun et al. (2015); Valdiani et al., (2019)
Bubble column bioreactors	- Simple design since mechanical agitation of the media is not necessary. -Due to the absence of moving parts, maintenance is simpler and the risk of contamination is reduced. -Lower shear stress effects. -Small energy consumption.	-Under high gas flow rates, significant foam formation occurs. -In very viscous fluids, poor fluid mixing occurs. -Separation of gas and liquid in the headspace.	Georgiev (2014); Mamun et al. (2015); Paek et al. (2001); Valdiani et al., (2019)
Airlift bioreactors	-Due to the absence of moving parts, maintenance is simpler and the risk of contamination is reduced. -Better oxygen transport and less shear stress than bubble column bioreactors. -Bubble coalescence is avoided by the medium’s clearly defined flow pattern.	-Under conditions of high gas flow rates, significant foam development occurs. -In excessively viscous fluids, there is poor fluid mixing. -High-density cultures have weak oxygen transport capability.	Georgiev (2014); Mamun et al. (2015); Paek et al. (2001); Valdiani et al., (2019)
Balloon-type bubble bioreactors	-Due to the absence of moving parts, maintenance is simpler and the risk of contamination is reduced. -Superior oxygen transport compared to bubble column bioreactors and less shear stress impact. -Bubble coalescence is avoided by the medium’s clearly defined flow pattern. -Scale-up process is easy	–	Kim et al. (2004); Shohael et al. (2005)
Gas-phase bioreactors
Nutrient mist bioreactors	-While the liquid phase is supplied as an aerosol containing droplets, the organs are present in the air phase and immobilized on mesh support. -This has the benefit of enhanced gas exchange, increased oxygen and nutrition availability, and decreased shear stress.	-The process of scaling up these bioreactors is challenging.	Georgiev (2014); Mamun et al. (2015); Valdiani et al., (2019)
Trickle-bed bioreactors	- In the air phase, the organs are immobilized on a stainless-steel matrix, and the liquid phase is administered as an aerosol with droplets. -In addition to enhanced gas exchange and decreased shear stress, this has the benefit of increasing oxygen and nutrition availability.	-Scaling up with these bioreactors is challenging.	Georgiev (2014); Mamun et al. (2015); Valdiani et al., (2019)
Temporary immersion bioreactors	-This type of bioreactor enables the cultivation of organs during cycles of immersion or non-immersion. -It operates on the fill-and-drain bioreactor concept, switching between cycles of the liquid and gas phases. -It is not agitated, and cultured organs are not subjected to mechanical stress.	-The scaling-up procedure is challenging with these bioreactors.	Etienne and Berthouly (2002); Georgiev et al. (2014); Mamun et al. (2015); Valdiani et al., (2019); Watt (2012)
Wave-mixed bioreactors	-The disposable bioreactors that use the wave-induced agitation principle are known as “wave bioreactors.” - Aeration parameters were successfully attained. -Contamination and foaming risks are minimal.	-Scaling up these bioreactors is challenging.	Georgiev (2014); Mamun et al. (2015); Valdiani et al., (2019)