Immobilized cell culture

Cell immobilized cultures of Phanerochaete chrysosporium and repeated-batch decolorization were reported by Yang and Yu [46]. Diazo-dye Red 533 was decolorized by PuF immobilized culture, and decolorization efficiency of 80% or higher was achieved within a period of 1 or 2 days. 

Choi, S.H., Moon, S.H., and Gu, M.B., Biodegradation of chlorophenols using the cell-free culture broth of Phanerochaete chrysosporium immobilized in polyurethane foam, J. Chem. Technol. Biotechnol., 77, 999-1004, 2002. 

Table 1 Proliferation of neurosphere-forming cells in cultures with or without EGF-immobilized...

Fungal cultures are used as free or immobilized cultures for decolorization processes under static and/or agitated conditions. Free cell cultures could decolorized... 

The immobilization of the white rot fungus F. trogii in Na-ALG beads allowed the decolorization of the dye Acid Black 52 in a stirred tank reactor operated in batch [55]. Three enzymes, laccase, MnP, LiP, secreted by fungus were reported during decolorization process. Results showed that laccase enzyme activity increased with increasing alginate concentration from 0 to 4%. Cell growth at immobilized cultivation was maintained more stably than suspended cultivation. Total amount of removed dye was reported to be 469 mg/L for immobilized cultures and 440 mg/L for suspended cultures. 

Cells immobilized in gels showed lower volumetric rates of hydrogen photoproduction as compared with immobilization on porous glass. In some cases, the diflusion limitation of the process rate was the main reason as shown above. In other cases thick layer of dense culture was insufficiently illuminated. The observation, that hydrogen production rate was higher when the layer of matrix was thinner, supports this suggestion (Tab. 3). 

Immobilized cell negative Cultured cells Harris (52)... 

Figure 26. Reconstruction of the tunica intima on the inner surface of a clinically used polyethylene terephtalate vascular prosthesis. A non-modified inner surface of the prosthesis, B immobilization of defined assemblies of protein molecules (e.g., collagenfiarninin or collagen+fibrin) on the inner surface of the graft, C immunofluorescence of von Willebrand factor, a marker of the identity a differentiation of vascular endothelial cells, in human saphenous vein endothelial cells in cultures on the inner surface of a prosthesis coated with collagen and larninin, D detail of a layer of endothelial cells growing on a layer of collagen and fibrin. Note well developed talin-containing focal adhesion plaques. A, B conventional optical microscope, C, D confocal microscope Leica DM 2500 [30,31].

The first experiments describing the clonal growth of hemopoietic progenitor cells immobilized in a soft gel matrix in vitro were reported by Bradley and Metcalf (1966) and Pluznick and Sachs (1965). Clonogenic cells are plated in the presence of various of feeder cells, medium conditioned by the growth of different tissues or cell lines in cultures (for example, 5637 bladder carcinoma conditioned media) and colony stimulating factors such as GM-CSF, G-CSF, M-CSF, Epo, interleukins. 

Villegas, M., Leon, R. and Brodelius P. E. 1999. Effects of alginate and immobilization by entrapment in alginate on benzophenanthridine alkaloid production in cell suspension cultures of Eschscholtzia californica. Biotechnology Letters, 21(1) 49-55. 

Three different approaches for the cultivation of isolated hematopoietic cells have been described, the static, the stirred and the immobilized culture. Static cultivation takes place in very simple culture systems like well plates, tissue-culture flasks or gas-permeable culture bags [62, 63]. As the first two systems do not allow cell cultivation on a clinical scale, the latter is actually the most often used technique for stem cell expansion. All these systems have the advantage of being easy to handle, single-use devices, which enable an uncomplicated cell harvest. But all of them do not offer possibilities for process control or continuous feeding. This causes variations in culture conditions during fermentation (e.g., oxygen tension, pH, substrate, metabolite and cytokine concentrations). 

The present study on butanol fermentation has been focused primarily on the effects of pH and dilution rate (D) in continuous cultures of the mutant strain from C. acetobutylicum ATCC 55025. To overcome the problems of low productivity and yield of butanol, cell immobilization in a convoluted fibrous bed bioreactor (FBB) and feeding with dextrose and butyric acid as cosubstrates to produce butanol and reduce production of ancillary byproducts were used in the fermentation. By changing the dilution rate from 0.1 to 1.2 h 1 at pH 4.3 and varying the pH from 3.5 to 5.5 at the dilution rate of 0.6 hr1, the optimal conditions for high productivity and butanol yield were investigated. 

Optimizing the ABE fermentation process has long been the aspiration of more than a century of research. Conventionally, the profitability of fermentation is influenced by the type and concentration of substrate, dilution rate, pH, culture medium, and product recovery. Even using cell recycle, cell immobilization, or extractive fermentation to increase cell density and productivity, the yield of the combined ABE production never exceeded 0.44 g/g (13-15). 

Embryogenic rice calli tend to form larger clumps during cultivation. Therefore, immobilization of the calli has hardly been carried out until now. Porous supports such as polyurethane foam have often been used for the immobilization of mycelial cells [64, 65] and plant cells [66-68]. In almost all cases, effective production of biological materials by the immobilized cells has been reported. To avoid the damage due to the hydrodynamic stress, we proposed the immobilization culture of rice callus using a macroporous urethane foam support. A turbine-blade reactor (TBR), which has been developed for hairy root culture, was also used in the culture. In the culture space, polyurethane foam was added as an immobilization support. 

Other experiments on the chitinolytic activity of immobilized cells and culture medium of carrot cells (Table V) indicate that chitosan, in concentrations available to plant cells during the preparation of kappa-carrageenan-chitosan coacervate capsules, is detrimental to chitinase activity in plant cells and culture medium. This is also of interest in light of the data presented on the elicitor effect of chitosan on chitinase production at minute chitosan concentrations (see Table IX). 

Table V. Chitinolytic activity of immobilized cells and culture medium of carrot (Daucus carota) cell cultures3...

In order to address the low cell density issue associated with sulfur-deprived cell suspensions, cell immobilization strategies have been investigated. This resulted in an 18 times increase in the H2-production rates on a per-cell culture volume basis and a 6 times longer period of H2 production by algal cultures immobilized on glass fibers.138 Additionally, the immobilized cultures have increased productivity (2.5 times) on a per illuminated area basis, compared to cell suspensions. 

Mucuna pruriens cell cultures are known to hydroxylate a variety of phenolic compounds (Pras, 1990). The solubility of the phenolic steroid, 1713-estradiol (Fig. 6.1), is only 12 pM in culture medium and no biotransformation products could be detected after administration to freely suspended cells, immobilized cells or partially purified Mucuna phenoloxidase. Complexation with (3-cyclodextrin dramatically enhanced the solubility of 17(3-estradiol. Alginate-entrapped cells, cell homogenates and the phenoloxidase were able to o-hydroxylate 17(3-estradiol when supplied as the cyclodextrin complex, the most efficient biotransformation being achieved with the isolated enz)mrie (Woerdenbag et at, 1990). 

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