Production hollow-fiber bioreactor

Commercial scale cultivation of mammalian cells is accompHshed using different technologies roller bottles, microcarriers, suspension (batch, fed-batch or perfusion mode) and hollow fiber bioreactors (Table 2). However, especially for products needed in large amounts, suspension cultivation seems to be the most effective system [4, 5]. Suspension-based systems are characterized by a homogeneous concentration of cells, nutrients, metabolites and product, thereby facilitating scale-up [6] and enabling an accurate monitoring and control of the culture [7]. 

A Simple Hollow-Fiber Bioreactor for the In-House Production of Monoclonal Antibodies... 

Parameters that are traditionally used to evaluate the metabolic activity of the cell population inside a hollow-fiber bioreactor include glucose consumption rate (rQLc) and oxygen consumption rate (rcu)- However, these parameters are highly dependent on variations in nutrient feed and metabolic products removal (Gramer et al., 1999). The use of a strategy to overfeed the ICS with nutrients results in a rapid increase in tglc- On the other hand, an increase in product titer and an improved metabolic... 

Products with less demand, such as those used in diagnosis, are developed in small-scale systems such as T-flasks, rollers, and hollow-fiber bioreactors (Kretzmer, 2002). The reduced size of these production systems makes it possible to operate various units in parallel to obtain different products. A small increase in scale can be reached by the multiplication of units. 

Hollow-fiber bioreactors constitute an optimized production system where it is possible to achieve higher cell concentrations (107 to 108 cells/ ml), and the product concentration can reach a level of 0.7-2.3 g/L, which is similar to what can be obtained with ascitic fluid (Hendriksen and Leeuw, 1998). This system can operate for over 3 months without affecting cell viability, but presents problems with mass transport, and the formation of nutrient gradients, which require specific solutions (Kretzmer, 2002). 

Gloeckner, H. Lemke, H.-D. New miniaturized hollow fiber bioreactor for in vivo like cell culture, cell expansion, and production of cell derived products. Biotechnol. Prog. 2001, 17, 828-831. 

Figure 8. Continuous production of rifamycin B in a dual hollow-fiber bioreactor.

Production of an optically active diltiazem intermediate (2R, 3S)-methoxyophenylglyci-date methyl ester ((-)-MPGM) from racemic MPGM by the action of lipase from Serratia marcescens in a toluene aqueous biphasic system (Tanabe Seiyaku Co., Ltd.). For the continuous production of (-)-MPGM, a hollow fiber bioreactor was set up in collaboration with Sepracor Inc. The introduction of this enzymatic step allowed the shortening of the diltiazem synthesis from nine down to five steps. 

The gaseous product from both bioreactors, enriched in H2 (20% H2) and devoid of any remaining CO, was sufficiently clean for direct injection into a H2 fuel cell. In fact, the effluent gas from the hollow-fiber bioreactor has been directly injected into small millivolt fuel cells and shown capable of generating enough electricity to power small motors and lamps. No negative effect on the fuel cells was noted. 

Antibody production from 8C2 cells growing within the hollow fiber bioreactor reached 240mg/wk by the third week. ATI was purified from the media through protein G affinity chromatography (Figure 6.5-5). Final ATI concentrations in the... 

Wee YJ, Yun JS, Kang KH, Ryu HW (2002) Continuous production of succinic acid by a fumarate-reducing bacterium immobilized in a hollow fiber bioreactor. Appl Biochem Biotechnol 98 1093-1104... 

Gilhes, R. J., P. G. Scherer, et al. 1991. Iteration of hybridoma growth and productivity in hollow fiber bioreactors using 31P NMR. Magn Reson Med 18(1) 181-192. 

Shi, Y., Ploof, J. and Correia, A. (1999) Increasing antibody production with hollow-fiber bioreactors, IVD Technol Mag. 5, 37-40. 

Lowrey, D., Murphy, S., and Goffe, R. A. (1994). A comparison of monoclonal antibody productivity in different hollow fiber bioreactors. J. Biotechnol. 36(1), 35-38. 

An example of an industrial membrane bioreactor is the hollow-fiber membrane system for the production of (-)-MPGM (3-(4-methoxyphenyl)glycidic acid methyl ester), which is an important intermediate for the production of diltiazem hydrochloride [81, 82]. For the enantiospecific hydrolysis of MPGM a hollow-fiber ultrafiltration membrane with immobilized lipase from Serratia marcescens is used. (-f)-MPGM is selectively converted into (2S,3J )-(-F)-3-(4-methoxyphenyl)glyci-dic acid and methanol. The reactant is dissolved in toluene, whereas the hydrophilic product is removed via the aqueous phase at the permeate side of the membrane, see Fig. 13.9. EnantiomericaUy pure (-)-MPGM is obtained from the to-... 

It is significant that the reaction mixture was worked up by removal of the unreacted ester by hexane extraction and concentration of the aqueous layer to obtain the desired (i )-amino acid. The process has a high throughput and was easy to handle on a large scale. However, because of the nature of a batch process, the enzyme catalyst could not be effectively recovered, adding significantly to the cost of the product. In the further scale up to 100-kg quantity productions, the resolution process was performed using Sepracor s membrane bioreactor module. The enzyme was immobilized by entrapment into the interlayer of the hollow-fiber membrane. Water and the substrate amino ester as a neat oil or hexane solution were circulated on each side of the membrane. The ester was hydrolyzed enantioselectively by the enzyme at the membrane interface, and the chiral acid product... 

Hypothetical example of the propagation of adherent cells, using hollow-fiber modules as the production bioreactor in the final stage. The amount of cells usually obtained at the end of each step is also indicated. 

As can be observed in Table 9.3, cell concentrations equal to or higher than 107 cells ml-1 are needed to attain volumetric productivities higher than 50 mg L-1 d-1. Also, it is important to note that as cell concentration increases, the complexity of the process increases and, consequently, bioreactor scale-up becomes limited, for example by physical limitations of materials used in hollow-fiber cartridges. 

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-... 

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