Diffusion-reaction-growth coupling in gel-immobilized cell systems: Model and experiment

Lefebvre, J.; Vincent, Jean-Claude

doi:10.1016/0141-0229(94)00036-q

Cited by 16 publications

(5 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, direct determination of intrinsic kinetics of immobilized cells is a very difficult task to accomplish. Thus, the intrinsic kinetics of supernatant cells, or the apparent or inherent kinetics of immobilized cells/enzymes, rather than the intrinsic kinetic parameters of immobilized cells is often used to analyze the kinetic behavior of immobilized cell beads (Lefebvre and Vincent, 1995;Meyerhoff et al, 1997;Bandhyopadhyay et al, 2001;Faqir and Attarakih, 2002). Meyerhoff et al (1997) examined the characterization and modeling of immobilized mixed cultures using intrinsic kinetic parameters of supernatant cells.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of effective diffusion coefficient and intrinsic kinetic parameters on azo dye biodegradation using PVA‐immobilized cell beads

Chen

Yang

et al. 2003

Biotech & Bioengineering

View full text Add to dashboard Cite

An immobilized mixed culture (Aeromonas hydrophila, Comamonas testosteroni, and Acinetobacter baumannii) was prepared by entrapment into phosphorylated polyvinyl alcohol (PVA) gel beads. The unsteady-state diffusion mechanism in a gel bead was applied to estimate the effective diffusion coefficients (D(e)) and the partition coefficients (K(p)) of azo dye. In addition, a simple method was developed to determine the intrinsic kinetic parameters of immobilized cells from observed reaction rates and the intrinsic kinetic parameters were then verified by fitting the experimental data into the reaction-diffusion model in a batch reactor running at a well-stirred state. The calculated effectiveness factor (eta(cal)) approached unity at Thiele modulus (Phi) < 0.3 (i.e., d(p) < 0.475 mm). The experimental effectiveness factor (eta(exp)) was in the range of 0.71-0.45 for a corresponding sphere diameter (d(p)) of 1.91 +/- 0.16 to 4.43 +/- 0.07 mm at an initial dye concentration of 200 mg/L. The results show that intraparticle diffusion resistance has a significant effect on the azo dye biodegradation rate.

show abstract

Section: Introductionmentioning

confidence: 99%

Evaluation of effective diffusion coefficient and intrinsic kinetic parameters on azo dye biodegradation using PVA‐immobilized cell beads

Chen

Yang

et al. 2003

Biotech & Bioengineering

View full text Add to dashboard Cite

show abstract

“…The quantity / P is the polymer volume fraction of gel and / C is the cell volume fraction of gel. The effect of immobilized cells on solute diffusion coefficients is considered quantitatively by Lefebvre & Vincent (1995) and Gutenwik et al (2002). One may expect that the solute diffusivities may vary during one run within the gel pores because of microbial growth.…”

Section: Mathematical Modelingmentioning

confidence: 99%

Lactic acid fermentation by cells of Lactobacillus rhamnosus immobilized in polyacrylamide gel

Petrov

Yankov

Beschkov

2005

World J Microbiol Biotechnol

View full text Add to dashboard Cite

The process of lactic acid fermentation of lactose to lactic acid by Lactobacillus rhamnosus ATCC 7469 has been studied. The following processes have been explored: growth kinetics, as well as lactose utilization, production of lactic acid and further degradation of lactic acid. The immobilization experiments were conducted with microbial cells entrapped in polyacrylamide gels. Gels with different ratios of the monomer (acrylamide) and the cross-linking agent (N,N¢-methylene-bis-acrylamide) have been tested. These were used in a repeat-batch process. The current processes inside and outside the gel particles were subjects of examination. The evolution of the activity of immobilized cells with repeated use showed that the particles served mainly as a donor of cells for the free culture. In all experiments a very high degree of conversion, 85-90% was observed. After several runs however, the particles were exhausted for microbial cells. A kinetic model of the process of lactic acid production was developed. This model allowed the evaluation of the effect of microbial growth and diffusion limitations inside the gel particles on the process rate and the separate contribution of the free and immobilized cells to the overall fermentation process upon multiple use.

show abstract

“…In some papers [9,10,19,20], more complete and realistic dynamic models have been developed taking into account the unsteady processes in the gel beads coupled with the mass transfer in the adjacent fermentation medium. However, the authors of these papers either have limited their studies to anaerobic processes only [9] or they have imposed a maximum possible biomass concentration within the particles pores [10,19,20,22]. This limiting maximum concentration requires either additional experimental measurements of immobilised biomass, or estimation from a dense packing of cells, intraparticle void volume fraction, etc.…”

Section: Mathematical Modellingmentioning

confidence: 99%

Dynamic modelling of aerobic bioprocesses in gel particles with immobilised cells

Beschkov

Велизаров

2000

Bioprocess Engineering

View full text Add to dashboard Cite

A dynamic model for aerobic growing cells immobilised into gel beads is developed and its operation is illustrated for the case of gluconic acid production by a strictly aerophilic strain of Gluconobacter oxydans. The model consists of both kinetic and mass transfer equations predicting the time course of bulk and intraparticle concentrations of substrates, products, and biomass. The model includes a product inhibition term. The parameter values are taken from own studies and from the literature. A sensitivity analysis of the model shows that the most signi®cant parameters for the process are the biotransformation rate constant, the speci®c cell growth rate in the bulk, and the Thiele modulus for glucose. The computer simulation reveals that depending on the parameter values the gel particles might perform as a source or a sink of the product, thus enhancing or retarding the net process. For a speci®c parameter selection, the biotransformation in the pellets can prevail compared with the bulk in the beginning of the process as long as the direction of the product diffusion¯ux is from the beads toward the bulk. Since the process in the free culture dominates, the system is more sensitive to parameters associated with the bulk phase (aeration rate, speci®c microbial growth rate, oxygen uptake rate). The model can be applied for prediction and fast evaluation of the performance of aerobic processes accomplished by immobilised growing cells.

show abstract

Diffusion-reaction-growth coupling in gel-immobilized cell systems: Model and experiment

Cited by 16 publications

References 28 publications

Evaluation of effective diffusion coefficient and intrinsic kinetic parameters on azo dye biodegradation using PVA‐immobilized cell beads

Evaluation of effective diffusion coefficient and intrinsic kinetic parameters on azo dye biodegradation using PVA‐immobilized cell beads

Lactic acid fermentation by cells of Lactobacillus rhamnosus immobilized in polyacrylamide gel

Dynamic modelling of aerobic bioprocesses in gel particles with immobilised cells

Contact Info

Product

Resources

About