Fiber Reactor

Another new class of structured reactors consists of different kinds of fiber or matt structures, coated with catalytically active materials. Typically, the fiber structures can be made from different polymeric materials, for example, polyethylene. These fibers can be freestanding (such as Smoptech Smopex , [13]) or knitted structures [ 14,15] with catalytically 

FIGURE 9.12 Comparison of two modeling approaches in the hydrogenation of citral on a Ni catalyst. Simulation with a BR model (—) and CSTR connected to parallel tubes with a plug flow model (...). 

FIGURE 9.13 (a) Three-phase continuous hydrogenation of an organic compound over a metal supported on silica fibers, (b) A scanning electron microscopy (SEM) image of a knitted silica fiber catalyst. 

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Hollow-fiber module Hollow-fiber reactor Hollow fibers... 

Hollow fiber reactors [7] and dialysis reactors [8] avoid shear stress by separating cells and flowing media. In both reactors nutrient supply takes place by diffusion through the capillary wall or the dialysis membrane. 

Hollow fiber reactor with adherent cells... 

The most advanced technology is the extracorporeal hollow fiber reactor. It is currently in Phase III trial and achieved a good Phase II record to support it. Other techniques including a polyurethane system devised in Japan and encapsulated hepatocytes from UCLA are or were in large animal trials. Whether a device is extracorporeal or is intended for implantation, clinical significance requires a suitable scaffold to support a sufficiently large colony of hepatic cells. For both extracorporeal and implant use, the physical structure of the scaffold must meet certain requirements of strength, void volume, biocompatibility, and other parameters. 

Hollow-fiber reactor - [CELL CULTURE TECHNOLOGY] (Vol 5)... 

Venkatadri R, Irvine RL. Cultivation of Phanerochaete chrysosporium and production of lignin peroxidase in novel biofilm reactor systems hollow fiber reactor and silicone membrane reactor. Water Res 1993 27 591-596. 

Another favorable aspect of stirred batch reactors is the fact that they are compatible with most forms of a biocatalyst. The biocatalyst may be soluble, immobilized, or a whole-cell preparation in the latter case a bioconversion might be performed in the same vessel used to culture the organism. Recovery of the biocatalyst is sometimes possible, typically when the enzyme is immobilized or confined within a semi-permeable membrane. The latter configuration is often referred to as a membrane reactor. An example is the hollow fiber reactor where enzymes or whole cells are partitioned within permeable fibers that allow the passage of substrates and products but retain the catalyst. A hollow-fiber reactor can be operated in conjunction with the stirred tank and operated in batch or... 

Finally, possible causes for deactivation of catalytic membranes are described and severad aspects of regenerating catalytic membrane reactors are discussed. A variety of membrane reactor configurations are mentioned and some unique membrane reactor designs such as double spiral-plate or spiral-tube reactor, fuel cell unit, crossflow dualcompartment reactor, hollow-fiber reactor and fluidized-bed membrane reactor are reviewed. 

The scale-up of hollow-fiber reactors and tubular reactors is easily performed by the multiplication of the number of fibers and tubes. 

Cass, B.J. et al., Production of tomato flavor volatiles from a crude enzyme preparation using a hollow-fiber reactor, Biotechnol. Bioeng., 67, 372, 2000. 

Hollow-fiber reactors are widely used in the production of MAb and can reach cell densities higher than... 

Patankar, D. Oolman, T. Wall-growth hollow-fiber reactor for tissue culture I. Preliminary experiments. Biotechnol. Bioeng. 1990,36,97-103. 

Fig. 3 Immobilized reactor systems (A) packed bed and (B) hollow fiber reactor.

Leon R, Prazeres DMF, Fernandes P, Molinari F, Cabral JMS. A multiphasic hollow fiber reactor for the whole-ceU bioconversion of 2-methyl-1,3-propanediol to (R)-P-hydroxyisobutyric acid. Biotechnol Prog 2001 17 468-473. 

The selectivity of metal catalysts improves in some reactions with alloying for example the alumina-supported Pd-Cu catalyst hydrogenates butadiene to 1-butene with 99% selectivity, i.e. the isomerization is less than 1%. The explanation is that hydrogen adsorption decreased on the Cu-containing catalysts" . Similarly, better selectivities were observed with a polymer anchored Pd, or a Pd-Co catalyst in the gas-phase hydrogenation of butadiene and cyclopentadiene in a hollow-fiber reactor" and in the liquid-phase hydrogenation of 1,5-hexadiene with Pd-Ag catalyst". ... 

Rossell, C. M., Vaidya, A. M., and Hailing, P. 1., Continuous in situ water activity control for organic phase biocatalysis in a packed bed hollow fiber reactor, Biotechnol. Bioeng., 49, 284-289, 1996. 

A membrane cell recycle reactor with continuous ethanol extraction by dibutyl phthalate increased the productivity fourfold with increased conversion of glucose from 45 to 91%.249 The ethanol was then removed from the dibutyl phthalate with water. It would be better to do this second step with a membrane. In another process, microencapsulated yeast converted glucose to ethanol, which was removed by an oleic acid phase containing a lipase that formed ethyl oleate.250 This could be used as biodiesel fuel. Continuous ultrafiltration has been used to separate the propionic acid produced from glycerol by a Propionibacterium.251 Whey proteins have been hydrolyzed enzymatically and continuously in an ultrafiltration reactor, with improved yields, productivity, and elimination of peptide coproducts.252 Continuous hydrolysis of a starch slurry has been carried out with a-amylase immobilized in a hollow fiber reactor.253 Oils have been hydrolyzed by a lipase immobilized on an aromatic polyamide ultrafiltration membrane with continuous separation of one product through the membrane to shift the equilibrium toward the desired products.254 Such a process could supplant the current energy-intensive industrial one that takes 3-24 h at 150-260X. Lipases have also been used to prepare esters. A lipase-surfactant complex in hexane was used to prepare a wax ester found in whale oil, by the esterification of 1 hexadecanol with palmitic acid in a membrane reactor.255 After 1 h, the yield was 96%. The current industrial process runs at 250°C for up to 20 h. 

Nguyen, T.V. Wu, J. C. S. Photoreduction of C02 to Fuels under Sunlight Using Optical-Fiber Reactor. Sol. Energy Mater. Sol. Cells, 2008, 92, 864-872. 

Figure 4. Glucose and pH histories in the effluent during the course of the dual hollow-fiber reactor operation. - o -, — - glucose cone., -A-, -A- pH. The filled circles and triangles represent the effluents containing E. coli cells.

After the experiment the reactor was dismantled and each of ten dual hollow-fiber units was visually examined. Only in 4 out of the ten fibers cells were densely packed, which suggests that the medium was not adequately supplied to many of these fibers. Probably the medium was not equally distributed among the fibers. In other words, in some of fibers the medium flow was not adequate to support the cell growth in the fiber. The nonuniform flow distribution among the fibers of a hollow fiber device is an intrinsic problem, which was studied in depth in the authors laboratory (16). The work of JL coli immobilization in the dual hollow fiber reactor was reported previously from the authors laboratory (17). 

This is not small at all if we consider that the residence time in the hollow-fiber reactor was 12 minutes based on the total fiber... 

Table 3.10 Lactose Hydrolysis Via Hollow Fiber Reactors...

Up to four enzymes involved in the metabolic pathways of purine bases-allantoinase, allantoicase, uricase and catalase-have been immobilized together by means of glutaraldehyde on the outer surface of cellulosic hollow fibers. Reactor performances are depicted in Figure 7.37, when uric acid is fed to the multi-enzyme reactor.71... 

Hydrolysis of raffinose Hollow fiber reactor with Production of monomeric... 

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