Airlift culture

Typical results in the author s laboratory (37-39) with Protocol 7 are 2.75 x 10 ° viable cells per htre giving an average yield of 166 mg/litre/day (compared to stirred reactor and airlift cultures of the same hybridoma of 25.5 and 18.5 mg/ litre respectively). This method is a low investment introduction to high productivity production of mAh which is simple to use and reliahle with low maintenance, at least for the first 50 days of culture. 

In an airlift fermenter, mixing is accomplished without any mechanical agitation. An airlift fermenter is used for tissue culture, because the tissues are shear sensitive and normal mixing is not possible. With the airlift, because the shear levels are significantly lower than in stirred vessels, it is suitable for tissue culture. The gas is sparged only up to the part of the vessel cross section called the riser. Gas is held up, fluid density decreases causing liquid in the riser to move upwards and the bubble-free liquid to circulate through the down-comer. The liquid circulates in airlift reactors as a result of the density difference between riser and down-comer. 

Prepare seed culture and use it for inoculation of 21 airlift and 21 B. Braun biostat B using soluble starch or glucose. 

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. 

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. 

The bioconversion process of Acid Orange 7 will be hereby analyzed. This is an incremental study with respect to that due to Lodato et al. [41], based on the operation of an airlift reactor with cells of Pseudomonas sp. 0X1 immobilized on natural pumice (density = 1,000 kg/m3 particle size = 800-1,000 pm). Details regarding the strain, medium, culture growth and main diagnostics of the liquid phase are reported by Lodato et al. [41]. Elemental analysis of dry biomass was obtained by a C/H/N 600 LECO analyzer. 

Tests were carried out at 25°C and at initial pH 6.9. Cultures in the liquid medium were incubated in 50 mL Falcon tubes, continuously shaked at 220 rpm. Each culture contained a fresh Pseudomonas sp. 0X1 colony in 10 mL of medium. The airlift with 10 g of pumice was sterilized at 121°C for 30 min and then housed in a sterile room. One-day culture was transferred to the reactor and, after a batch phase, liquid medium with phenol as the only carbon source was continuously fed. The reactor volume V was fixed at 0.13 L. Aerobic conditions were established sparging technical air. Under these conditions microorganism started to grow immobilized on the solid s support. When immobilized biomass approached steady state, cyclic operation of the airlift was started by alternating aerobic/anaerobic conditions. 

Figure 10.6 Helical photobioreactor for testing the effects of growth parameters during continuous H2 production. The test reactor was constructed from SOm of PVC tubing, wound round a wire former, and contained 3 I of a culture of A. variabilis. An airlift flushed the culture with air -t 2 per cent CO2, and circulated it through a degasser and computer-controlled monitoring equipment (Borodin et al. 2000).

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. 

Several different bioreactor configurations have been described for use in cell culture and fermentation applications. These include stirred tanks, airlift, and hoUow-fiber systems. The majority of bioreactor systems in use for cell culture applications are still of the stirred-tank type. These systems have been used for batch, fed-batch, and perfusion operations. It would not be possible to adequately cover the field of stirred-tank scale-up in the space available here. Instead, this section will touch briefly on the important issues in bioreactor scale-up. For detailed methodologies on stirred-tank bioreactor scale-up, the reader is referred to several review papers on the topic [20,27,28]. 

Until now, bioreactors of various types have been developed. These include loop-fluidized bed [14], spin filter, continuously stirred turbine, hollow fiber, stirred tank, airlift, rotating drum, and photo bioreactors [1]. Bioreactor modifications include the substitution of a marine impeller in place of a flat-bladed turbine, and the use of a single, large, flat paddle or blade, and a newly designed membrane stirrer for bubble-free aeration [13, 15-18]. Kim et al. [19] developed a hybrid reactor with a cell-lift impeller and a sintered stainless steel sparger for Thalictrum rugosum cell cultures, and cell densities of up to 31 g L1 were obtained by perfusion without any problems with mixing or loss of cell viability the specific berberine productivity was comparable to that in shake flasks. Su and Humphrey [20] conducted a perfusion cultivation in a stirred tank bio-... 

Flower [25], Panda et al. [26], Doran [27]. and Payne et al. [28]. Several kinds of bioreactors, such as the stirred tank bioreactor with hollow paddle and flat blade impellers, the bubble column, the airlift bioreactor with internal and external loops, the rotating drum bioreactor, the stirred-tank with a draft tube, and the mist bioreactor have been attempted for plant cell, tissue and organ cultures (Fig. 1). 

Kreis, W. and Reinhard, E. (1990b) 12-Hydroxylation of digitoxin by suspension-cultured Digitalis lanata cells production of digoxin in 20 litre and 300 litre airlift bioreactors. ]. Biotechnol, 16,123-36. 

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