BIOREACTORS FOR PLANT CELL ANDTISSUE CULTURES

Bioreactor production of useful and valuable metabolites in plant cell and tissue cultures as well as mass propagation procedures on a large scale have been carried out since the end of the 1950s.

Patents focused on the industrial application of this technology in the 1980s.

Industrial applications (e.g., production of shikonin, taxol, ginseng, biomass, berberine.

Bioreactor

The bioreacto so-called heart of biotechnological production processes—has a key position here

Their modifications, their instrumentation, and the operational strategy for mass propagation

GENERAL REQUIREMENTS

1. Homogeneous and low-shear mixing for efficient nutrient transport without sedimentation and/or clumping as well as loss of cell viability

2. Optimal aeration with low shear stress.

3. Guarantee of the long-term sterility of the process as a practical consequence of slow growth rates

4. Introduction of light for heterotrophic, photomixotrophic, and photoautotrophic cultures for increasing the biosynthetic capacities

INSTRUMENTATION OF BIOREACTORS

bioreactor's configuration associated with reactor instrumentation.

The eight main reactor types

Types

A. Stirred Reactor

The ordinary stirred reactor (Fig. 3a) is equipped with baffles, air sparger and radial flow impellers, axial flow impellers, and impellers distributing the power input over a large fraction of the total reactor volume.

Different flow patterns and shear rates inside the vessel will be produced by different impeller shapes, sizes, and spacing (multiple stirrers) as well as installation of a coaxial draught tube

Stirred Reactor

Its typical fermenter geometry (fermenter height/diameter ratio) must be 2:1 or 3:1. Mixing and mass dispersion are achieved by mechanical agitation.

It is also possible to design and operate stirred reactors in a multistage mode.

Stirred Reactor

B. Rotating Drum Reactor Mass and energy inputs are realized by

drum self-rotation in the rotating drum reactor.

Systems with one reactor-chamber work with a long axis designed as a hollow shaft for air and gas exchange.

Transport processes inside the reactor can be varied by the drum rotation rate.

B. Rotating Drum Reactor If there is the demand for low

hydrodynamic shear stress conditions and high oxygen transfer rates for non-Newtonian cultures, the rotating drum reactor should be preferred to standard stirred reactors

C. Bubble Column

Another alternative to the stirred reactor that has no mechanical agitation and is structurally very simple.

Mass and energy inputs are achieved only by pneumatic driving (gas sparging).

Advantages of this reactor type are low capital cost and minimized problems of sterility based on lack of moving parts inside the reactor

C. Bubble Column

C. Bubble Column

Bubble columns can be divided into five main types of reactors on the basis of their structure:

1) simple column reactors,2) multistage perforated plate column

reactors3) multistage column reactors with static

mixers for repeated gas dispersion,4) column reactors with nozzle aeration5) tower reactors.

D. Airlift Reactor

mass and energy input in airlift reactors is accomplished pneumatically without mechanical agitation and associated with significantly lower shear levels than in stirred reactors.

It should be pointed out that airlift reactors generally provide better mixing conditions than the bubble columns described.

D. Airlift Reactor

The use of a draught tube divides the flow in a riser

and downcomer, and the density difference enables the liquid to circulate.

Three common airlift configurations, the internal loop airlift reactor, the external loop airlift reactor, and the draught tube airlift reactor, are shown in Fig. 4b-d.

D. Airlift Reactor

E. Packed Bed Reactor

The typical packed bed reactor consists of a vertical column packed with cells and adsorbents such as polymeric beads.

The nutrient medium can be fed either at the top or bottom of the tube and is circulated through the packed bed.

air is sparged indirectly by aeration of a separately used storage vessel as well as a recycling medium vessel

F. Fluidized Bed Reactor

When packed beds are operated in upflow mode, the bed expands at high liquid flow rates and follows the motion of the particles, where the particles are in a constant motion.

G. Trickle Bed Reactor

The trickle bed reactor is one variation of the packed bed configuration.

One or a number of nozzles integrated in the headspace of the column spray the nutrient continuously or periodically onto the top of the packaging.

The aeration takes place directly by introducing air at the base.

A special version of the trickle bed reactor is the mist reactor.

H. Membrane Reactor

The membrane filter assembly is responsible for mass exchange, for example, a continuous separation of product in the course of the cultivation process.

The whole culture medium inside the bioreactor represents permeate.