Bioreactor cell immobilization

Fan, L. S., Fujie, K., Long, T. R., and Tang, W. T., Characteristics of Draft Tube Gas-Liquid-Solid Fluidized-Bed Bioreactor with Immobilized Living Cells for Phenol Degradation, Biotechnol. Bioeng., 30 498 (1987b)... 

On the other hand, cell immobilization on carriers definitively improves bioreactor efficiency. Cell aggregation in a biofilm structure increases process stability and tolerance to shock loadings. A proper selection of operating conditions allows... 

K. F. Gu and T. M. S. Chang, Production of essential L-branched-chain amino acids in bioreactors containing artificial cells immobilized multienzyme systems and dextran-NAD+, Biotechnol. Bioeng., 36, 263-269 (1990). 

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. 

Aspartase. Tanabe Seiyaku has used aspartase in lysed E. coli cells immobilized by entrapment in polyacrylamide (3) or K-carra-geenan (38) for production of aspartic acid since 1973. Using a substrate stream containing 1 M ammonium fumarate and 1 mM Mg2+ at pH 8.5 and 37°C, a continuous, automated bioreactor with a 120-day half-life will produce L-aspartate at 60% of the cost of a batch fermentation (3). Recently, a process for immobilization of the cells in polyurethane has also been described (37). 

Konovalova VV, Dmytrenko GM, Nigmatullin RR, Bryk MT, and Gvozdyak PL Chromium(Vl) reduction in a membrane bioreactor with immobilized Pseudomonas cells. Enzyme Microbial Technol, 2003 33(7) 899-907. 

A new bioreactor, consisting of a liquid-gas two-phase system, was devised for utilization with berberine-secreting T. minus cells immobilized in calcium alginate beads. The cells were alternately soaked in medium, and then exposed to air, and the maximum yield of berberine production was 875 mg/L. The berberine productivity of immobilized cells was as high as that of freely suspended cells under such conditions of batch culture. In addition, the rate of production of berberine by the immobilized cells remained constant at a high value (50 mg/L/day) for 60 days of semicontinuous culture, achieved by the renewal of medium at 10 day intervals [154]. 

Enzymes are proteins that have been optimized by evolution for more or less specific metabolic reactions in living cells. Reaction conditions therein are often far away from those in industrial bioreactors. By immobilization novel characteristics can be induced to make enzymes tolerant to even harsh reaction environments. Some attempts to intentionally modify the catalytic behavior have been reviewed [15]. The immobilization procedure should be conducted in a way that allows the enzyme to maintain its active conformation and necessary catalytic flexibility. Furthermore, catalytically essential residues of the enzyme should be undisturbed and conserved. 

Dual Hollow-Fiber Bioreactor for Aerobic Whole-Cell Immobilization... 

Fig. 2 The effects of recirculation flow rate on cell immobilization efficiency in a packed-bed bioreactor. Cell density=50 g/L...

Fixed-bed bioreactors, using Immobilized P. aeruginosa cells are suitable for the simultaneous or separate removal of nitrates and heavy metals from very diluted solutions. The availability of a large amount of plastic waste makes it attractive as a cheap carrier for waste removal. The choice of plastic depends on the intended application for denitrification PVC is adequate (maximum viability of cells but less stability), for Pu removal PP is better (maximum stability, lessened viability). The plastic based bioreactors are highly competitive with others both in performance and in economy. 

Total alkaloid production of C. roseus cells immobilized on the surfaces of calcium alginate beads in a packed column bioreactor is described by Kargi (627). The alkaloid concentration of the medium and the biomass was determined by means of absorbance measurements at 280 nm. A calibration curve was established with the alkaloid ajmalicine. Total alkaloid content of medium and cells was claimed to be as high as 3.3% on dry weight basis, whereas the alkaloid content of suspension cultured cells was 0.4%. 

Kuyukina MS, Ivshina IB, Serebrennikova MK, Krivorutchko AB, Podorozhko EA, Ivanov RV, Lozinsky VI (2009) Petroleum-contaminated water treatment in a fluidized-bed bioreactor with immobilized Rhodococcus cells. Int Biodeter Biodegr 63 427 32... 

Bioreactors with immobilized enzymes or whole cells are utilized in a variety of areas. EMR have found widespread applications in the hydrolysis of macromolecules - proteins, poly- and oligosaccharides, lipids, etc. - for food and pharmaceutical applications (Prazeres and Cabral, 1994). More recently they have also begun to find application for the removal of various pollutants from wastewaters. An overview of the literature in these fields is described below. 

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