Airlift bioreactor

M. Y. Chisti, Airlift Bioreactors, Elsevier AppHed Science, New York, 1989. 

In applications of airlift bioreactor there are various types of fermenter. The most common airlift bioreactors are pressure cycle, internal and external loop bioreactors. 

The gas is circulated by means of pressurised air. In airlift bioreactors, circulation is caused by die motion of injected gas through a central tube, with fluid recirculation through the annulus between die tube and the tower or vice versa. Figure 6.1 shows an airlift bioreactor widi an internal loop cycle of fluid flow. 

A modified type of airlift system widi gas and liquid flow patterns in which a pump transports the ah and liquid through die vessel. Here, an external loop is used, with a mechanical pump to remove the liquid. Gas and circulated liquid are injected into the tower through a nozzle. Figure 6.2 shows an airlift bioreactor diat operates widi an external recirculation pump. 

Fig. 6.2. Airlift bioreactor with external recirculation pump.

Glasgow LA, Jones GT, Erickson LE (1989) Hydrodynamic characterization of airlift bioreactor operation. In Two-Phase Flows, Tapie, Tawan... 

The aims of the present work were to culture H. pluvialis in the airlift bioreactor in order to examine the effect of superficial gas velocities on growth of H. pluvialis. 

Figure 1 shows that high superficial gas velocity in the airlift bioreactor obviously inhibited growth of H. pluvialis. In this study, the best superficial gas velocity for growth of H. pluvialis was found at the lower limit of the experiment (0.4 cm s ), which providing the maximum cell density and maximum specific growth rate of 77x10 cells mL (2.79 g L of... 

Figure 1 Growth curve ofH. pluvialis at different superficial gas velocities (Ug=0.4,2, 2.5, 3 cm s" ) in 3L airlift bioreactor (Aa/Ar=3.2).

This work demonstrated that an airlift system was suitable for the cultivation of Haematococcus pluvialis, one of the most effective microorganisms that could produce high potential antioxidant carotenoid, astaxanthin. Aeration was shown to be crucial for a proper growth of the alga in the airlift bioreactor, but it must be maintained at low level, and the most appropriate superficial velocity was found to be at the lower limit of the pump, i.e. 0.4 cm s". ... 

L airlift bioreactor respectively [130]. The slow growth rate of plant cells leads to a high possibility of contamination during the cell culture, thereby increasing the production cost. Thus, efforts have been made towards alternative hosts, like engineering microbes to produce Taxol. 

Navia-Osorio, A., Garden, H., Cusido, R.M. et al. (2002) Production of paclitaxel and baccatin III in a 20-L airlift bioreactor by a cell suspension of Taxus wallichiana. Planta Medica, 68, 336-340. 

The draft-tube airlift bioreactor was studied using water-in-kerosene microemulsions [263], The effect of draft tube area vs. the top-section area on various parameters was studied. The effect of gas flow rates on recirculation and gas carry over due to incomplete gas disengagement were studied [264], Additionally, the effect of riser to downcomer volume was also studied. The effect of W/O ratio and viscosity was tested on gas hold-up and mass transfer coefficient [265], One limitation of these studies was the use of plain water as the aqueous phase in the cold model. The absence of biocatalyst or any fermentation broth from the experiments makes these results of little value. The effect of the parameters studied will greatly depend on the change in viscosity, hold-up, phase distribution caused due to the presence of biocatalyst, such as IGTS8, due to production of biosurfactants, etc., by the biocatalyst. Thus, further work including biocatalyst is necessary to truly assess the utility of the draft-tube airlift bioreactor for biodesulfurization. 

Mehrnia, M. R. Towfighi, J. Bonakdarpour, B., and Akbarnejad, M. M., Gas hold-up and oxygen transfer in a draft-tube airlift bioreactor with petroleum-based liquids. Biochemical Engineering Journal, 2005. 22(2) pp. 105-110. 

Gamier, A., Chavarie, C., Andre, G., and Klvana, D., The Inverse Fluidization Airlift Bioreactor, Part I Hydrodynamic Studies, Chem. Eng. Comm., 98 31 (1990)... 

B.) The yield of recombinant HSA, as determined using an enzyme-linked immunosorbent assay (ELISA). The sprouts were germinated in an airlift bioreactor tank for 175 hours in the presence or absence of 20 mM KN03. Recombinant HSA was expressed under the control of the Rbc56 promoter isolated in our laboratory. 

Fig. 5 Experimental apparatus (A) airlift bioreactor (B) gas flow control unit (C) humidifier (Dj) medium tank (D2) dye solution tank (D3) wastewater tank (E) liquid flow control unit...

Airlift bioreactors, 1 740-742, 744 oxygen transfer driving force, 1 735 Airlift devices, estimating shear rates for, 15 689... 

External humidification, 12 213 External interface management, in technology transfer, 24 366 External loop airlift bioreactors, 1 741, 742 Externally manifolded fuel cells, 12 200 External magnetic field, 23 835 External mass transfer, 15 728-729 External mass transfer resistance dimensionless parameter and,... 

Internal loop airlift bioreactors, 1 742 Internal manifolding method, 12 200 Internal microwave field, 16 513 Internal olefins, sulfonation of, 23 527 Internal-pair formation (IPF),... 

Industrial hazardous wastewater can be treated aerobically in suspended biomass stirred-tank bioreactors, plug-flow bioreactors, rotating-disc contactors, packed-bed fixed-biofilm reactors (or biofilters), fluidized bed reactors, diffused aeration tanks, airlift bioreactors, jet bioreactors, membrane bioreactors, and upflow bed reactors [28,30]. 

Breuling, M., Alfermann, A. W. and Reinhard, E. 1985. Culivation of cell cultures of Berberis wilsoniae in 20-1 airlift bioreactors. Plant Cell Reports, 4 220-223. 

Rhizosecretion is easy to scale up and very cost effective with respect to isolation and purification. However, the bioreactor systems used for hairy root cultures differ from those used for plant cell suspensions. Traditional bioreactor systems have recently been adapted for root culture, and this technology is now being taken to commercial scales. The most traditional system is the airlift bioreactor used for microorganisms or plant cells. This system is adapted for the culturing of roots in liquid medium. Mist culture systems have also been developed. For this technology, the volume of the culture medium is reduced and the concentration of the secreted therapeutic protein is increased. If the protein to be produced is known to be quite stable, then a less expensive hydroponic culture can be designed in a manner suitable for scale-up. 

Immobilisation of an Acetobacter aceti strain in calcium alginate resulted in improvement of the operational stability, substrate tolerance and specific activity of the cells and 23 g phenylacetic acid was produced within 9 days of fed-batch cultivation in an airlift bioreactor [133]. Lyophilised mycelia of Aspergillus oryzae and Rhizopus oryzae have been shown to efficiently catalyse ester formation with phenylacetic acid and phenylpropanoic acid and different short-chain alkanols in organic solvent media owing to their carboxylesterase activities [134, 135] (Scheme 23.8). For instance, in n-heptane with 35 mM acid and 70 mM alcohol, the formation of ethyl acetate and propylphenyl acetate was less effective (60 and 65% conversion yield) than if alcohols with increased chain lengths were used (1-butanol 85%, 3-methyl-l-butanol 86%, 1-pentanol 91%, 1-hexanol 100%). This effect was explained by a higher chemical affinity of the longer-chain alcohols, which are more hydrophobic, to the solvent. 

M.A. Young, R.G. Carbonell, D.F. Ollis, Airlift bioreactors analysis of local two-phase hydrodynamics, AIChE J. 37 (1991) 403-428. 

Fig. 4. Schematic diagram of a concentric-tube airlift bioreactor (with working volume of 1.0 1). 1 Reactor column 2 inner draft tube (with its height of 15 cm) 3 sparger B bottom clearance (2.5 cm) d diameter of draft tube (4.5 cm) D reactor diameter (7.0 cm) H column height (40 cm)...

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