Bioreactor continuous stirred

Figure 11.9 Different arrangements and modes of operation for membrane bioreactors Continuous Stirred Tank Reactor (CSTR) with recirculation arrangement (a), dead-end cell (b), tubular with entrapped enzyme (c).

Laska ME, Cooney CL. (2002) Bioreactors, continuous stirred-tank reactors. In FUckinger MC, Drew SW, editors. Encyclopedia of Bioprocess Technology, John Wiley Sons, Inc., New York, USA. p 353-371. 

Bioreactors a) batch stirred tank b) continuous stirred tank c) continuous packed-bed i) downward flow, ii) upward flow and iii) recycle d) continuous fluidised-bed e) continuous ultrafiltration. Redrawn from Katchalski - Katzir E. (1993) Trends in Biotechnology II, 471-477. 

The mass transfer, KL-a for a continuous stirred tank bioreactor can be correlated by power input per unit volume, bubble size, which reflects the interfacial area and superficial gas velocity.3 6 The general form of the correlations for evaluating KL-a is defined as a polynomial equation given by (3.6.1). 

Fig. 4.1. Instrumentation control for continuous stirred tank (CSTR) bioreactor.

The medium for enzyme production was completely synthetic and limited in carbon to prevent excessive growth of mycelia. It contained glucose 2 g/l plus ammonia nitrogen, vitamins and trace elements according to Leisola et al.(ii). The 100 1 inoculum was transferred into 8001 of medium in a 10001 bioreactor equipped with 12 rrfi of nylon wool sheets supported by steel wire screen (Figure 1). The medium was continuously stirred with the impeller (100-200rpm) and saturated with pure oxygen. The temperature was maintained at 37°C. 

Figure 3. Autoradiographic detection of naphthalene degradative bacterial colonies from MGP soil enrichments used as inoculum for continuous stirred soil slurry bioreactors.

Similar behavior to that of the nonisothermal CSTR system will be observed in an isothermal bioreactor with nonmonotonic enzyme reaction, called a continuous stirred tank enzyme reactor (Enzyme CSTR). Figure 3.27 gives a diagram. 

Breese, T.W. and Admassu, W. (1999) Feasibility of culturing c2cl2 mouse myoblasts on glass microcarriers in a continuous stirred tank bioreactor. Bioprocess Eng. 20, 463-468... 

The production of substances that preserve the food from contamination or from oxidation is another important field of membrane bioreactor. For example, the production of high amounts of propionic acid, commonly used as antifungal substance, was carried out by a continuous stirred-tank reactor associated with ultrafiltration cell recycle and a nanofiltration membrane [51] or the production of gluconic acid by the use of glucose oxidase in a bioreactor using P E S membranes [52]. Lactic acid is widely used as an acidulant, flavor additive, and preservative in the food, pharmaceutical, leather, and textile industries. As an intermediate product in mammalian metabolism, L( +) lactic acid is more important in the food industry than the D(—) isomer. The performance of an improved fermentation system, that is, a membrane cell-recycle bioreactors MCRB was studied [53, 54], the maximum productivity of 31.5 g/Lh was recorded, 10 times greater than the counterpart of the batch-fed fermentation [54]. 

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-... 

While the Monod equation is an oversimplification of the complicated mechanism of cell growth, it often adequately describes fermentation kinetics. The Monod kinetic parameters can be determined by making a series of ideal continuous stirred-tank bioreactors, which will be discussed later. Table 19.6 shows the typical values of the Monod s kinetic parameters when glucose is a limiting substrate. 

Eor an ideal continuous stirred-tank bioreactor (CSTB), the concentrations of the various components of the outlet stream are assumed to be the same as the concentrations in the bioreactor. Continuous operation of a bioreactor can increase the productivity of the reactor significantly by eliminating the downtime and the ease of automation. 

Two fundamentally different types of bioreactor setups can be distinguished. In the first type of reactors, MTBE-degradation occurs by bacteria in suspension in continuously stirred tank reactors (CSTR) (Table 6). An obvious advantage of this setup is the optimal mixing of MTBE-degrading biomass, contaminants and oxygen, reducing transport Hmitations to a minimum. However, specialized adaptations are required to prevent washout of biomass from the reactor. Three different methods exist. 

Altuntas E.G. and Ozcelik F. Ethanol production from starch by co-immobilized amyloglucosidase— Zymomonas mobilis cells in a continuously-stirred bioreactor. Biotechnology and Biotechnological Equipment 27 (1) (2013) 3506-3512. 

To choose the adequate bioreactor design for continuous PHA production, kinetics for both biomass and PHA production by the microbial strain should be considered. In the case of PHA production directly associated with microbial growth as it is found in Alcaligenes latus DSM 1122 on sucrose [128], or for Pseudomonasputida ATCC 29147 on fatty acids [97,98], a one-step continuous process using a continuous stirred tank reactor (CSTR) is a viable solution. 

Sokol, W, and Migiro, C.L.C. (1996), Controlling a continuous stirred-tank bioreactor degrading phenol in the stability range, The Chemical Engineering Journal and The Biochemical Engineering Journal, 62(1) Cl-12. 

Steady-state flow reactors, with a constant supply of reactants and continuous removal of products, can be operated as both a continuous stirred-tank bioreactor (CSTB) and as a plug flow bioreactor (PFB). It is possible to have different configurations of the membrane bioreactor where the biocatalyst is immobilized in the fractionated membrane support (Katoh and Yoshida, 2010). In Fig. 1.6 the scheme of a CSMB in which the biocatalyst is immobilized on the surface of the membrane beads is presented. The biocatalyst immobilized in the porous structure of a fractioned membrane can also be operated in CSMB. For example, two configurations are shown in Fig. 1.7 (a) for flat-sheet and (b) for spherical porous structures, respectively. Such structures could also be adopted for PFB, where a bed of membrane support with the immobilized biocatalyst could be utilized, in either a fixed or fluid configuration. 

Krebser, U., H. P. Meyer, and A. Fiechter, A Comparison between the Performance of Continuously Stirred-Tank Bioreactors and a TORUS Bioreactor with Respect to Highly Viscous Culture Broths, J. Chem. Tech. Biotechnol., 43, 107, (1988). 

A similar approach, starting with a material balance, can be used for the characterization of bioreactors operating in the continuous mode. Thus, for a perfectly mixed reactor, or continuous stirred tank reactor (CSTR), where the term of accumulation is zero at steady state and the liquid composition is uniform, the material balance for substrate A is given by Equation 7.7 ... 

In a continuous stirred tank reactor, a cmstant flow of reacliai substrates is fed to the reactor, where the immobilized lipase is suspoided in an agitated vessel. The main character of this type of reactitm is that Ihae is no tanperature or concentration gradients due to efficient mixing that promotes intimate contact of the reaction mixture with the immobilized lipase. Like batchwise reactors, immobilized lipase can be retained within the bioreactor by filtration. This is known to have lower construction cost. However, it requires larger volumes than a PER to achieve the same reaction. Commonly, a microfilter is provided at the bioreactor outlet to prevent immobilized lipase from leaving the reactor. 

Various bioreactors (batch stirred tank reactors, continuous packed bed, stirred tank, fluidized bed and membrane) have been used with varying efficiencies. Generally, stirred tank reactors are found to be less efficient than continuous ones (Macrae, 1985b Sawamura, 1988) due to... 

Table 13.1 Equations used to calculate reaction-rate in batch and continuous stirred UF-membrane bioreactors.

Chemostat continuous stirred tank fermenter Fed-batch fermenter Fluidized bed bioreactor... 

Cells in suspension Plug flow reactor with hydrodynamic stirring with or without static mixing elements in tube or flat-bed bioreactor Continuous... 

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