Diffusional characteristics of a swelling gel and its consequences for bioreactor performance

Axelsson, Anders; Sisak, Cs.; Westrin, Bengt A.; Szajáni, B.

doi:10.1016/0923-0467(94)87015-2

Cited by 8 publications

(8 citation statements)

References 12 publications

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“…Data presented for mass transfer in gels by several authors (3, 5 − 7, 11, 12) show that the increase in gel concentration is accompanied by a decrease in diffusivity: η g = D g / D 0 = ϵ g / T g , where ϵ g is the gel porosity or void fraction, and T g is the gel pore network tortuosity. Moreover, the effect of porosity when T g = 1.0 is assumed is not enough to explain the decrease in diffusivity.…”

Section: Data Model Analysis and Discussionmentioning

confidence: 99%

Immobilized Particles in Gel Matrix-Type Porous Media. Homogeneous Porous Media Model

Мота¹,

Teixeira²,

Yelshin³

2001

Biotechnol. Prog.

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Diffusion in pure gels and gels with immobilized cells was analyzed. A model of diffusion assuming a homogeneous cell distribution in gel was improved by introducing a tortuosity value. By theoretical analysis and numerical modeling it was shown that the tortuosity of a gel with immobilized cells is the product of two factors: (1) tortuosity generated by the cells, T c , and (2) tortuosity of the gel matrix, T g , both variables being a function of cell volume fraction, φ c . Total tortuosity is thus T Σ ) T c T g . On the basis of this approach, it was possible to analyze diffusivity data for gels with immobilized cells. It was shown that, in these systems, the diffusivity η ) D e /D 0 is a complex function of (1) diffusivity in the gel, η g , and (2) diffusivity in immobilized cells, η c . The developed model allowed for the description of the dependence of D e /D 0 on φ c . Comparison with numerous published experimental data showed a good fit. Observed deviations might be explained by nonhomogeneous cell distributions inside the gel matrix.

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Section: Data Model Analysis and Discussionmentioning

confidence: 99%

Immobilized Particles in Gel Matrix-Type Porous Media. Homogeneous Porous Media Model

Мота¹,

Teixeira²,

Yelshin³

2001

Biotechnol. Prog.

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“…Polyacrylamide has been widely used in immobilization of microorganisms and enzymes (Axelsson et al, 1994;Cottenceau et al, 1990;Pizarro et al, 1997;Sadhukhan et al, 1993;Seip and Cosimo, 1992;White and Thomas, 1990). Its use in cell immobilization has many advantages, but spherical beads are difficult to produce.…”

Section: Cell Immobilizationmentioning

confidence: 99%

Hydrogenotrophic denitrification with immobilized Alcaligenes eutrophus for drinking water treatment

Chang

Tseng

Huang

1999

Bioresource Technology

104

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“…Gels are one of the most widely used supports; these can be either natural, derived from polysaccharides such as agar 12) , alginate 13) , j-carrageenan 14) or synthetic, such as the gels derived from acrylamide 15,16) . An acrylamide-derived gel is a crosslinked network of polymers whose molecular weight is very high; it can adsorb solvent, principally water, but is insoluble itself 17) .…”

Section: Introductionmentioning

confidence: 99%

The effect of external stimuli on the invertase adsorption capacity of poly(N-vinyl-2-pyrrolidone-co-itaconic acid) hydrogels

Tümtürk

aykara²,

Kantoğlu

et al. 1999

Angew. Makromol. Chem.

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Polyelectrolyte Poly(N‐vinyl‐2‐pyrrolidone‐co‐itaconic acid) hydrogels (P(VP/IA)) with varying compositions were prepared from ternary VP/IA/water mixtures. The effect of external stimuli such as pH of the solution, temperature, substrate concentration of solution, and storage stability on the invertase adsorption capacity of P(VP/IA) hydrogels was investigated. The adsorption capacity of the hydrogels was found to increase from 4.4 to 18.4 mg invertase/g dry gel with increasing amount of IA in the gel system, while P(VP) gel adsorbed only 3.1 mg invertase/g dry gel. Kinetic parameters were calculated as Michaelis‐Menten constant Km = 20.6 mmol L–1 and maximum velocity Vmax = 6.44×10–5 mol dm–3 min–1 for free enzyme and in the range of Km = 26.4–41.1 mmol L–1 and Vmax = 6.35·10–5–6.66·10–5 mol dm–3 min–1, depending on the amount of IA in the hydrogel. Enzyme activities were found to increase from 59.0% to 72.0% with increasing amount of IA in the gel system and retained their activities for one month storage. The enzyme activities, after storage for one month at 4°C, were found to be 21.0% and 59.0–74.0% of the initial activity values for free and adsorbed enzyme, respectively. The optimal pH values for free and adsorbed enzymes were determined as 4.56 and 5.00, respectively. The optimum temperature for free and adsorbed enzymes was 55°C. Adsorption studies have shown that not only the gel composition but also the stimuli, temperature and pH of the solution play an important role on the invertase adsorption capacity of poly(VP/IA) hydrogels.

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Diffusional characteristics of a swelling gel and its consequences for bioreactor performance

Cited by 8 publications

References 12 publications

Immobilized Particles in Gel Matrix-Type Porous Media. Homogeneous Porous Media Model

Immobilized Particles in Gel Matrix-Type Porous Media. Homogeneous Porous Media Model

Hydrogenotrophic denitrification with immobilized Alcaligenes eutrophus for drinking water treatment

The effect of external stimuli on the invertase adsorption capacity of poly(N-vinyl-2-pyrrolidone-co-itaconic acid) hydrogels

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