Diffusion characteristics of different molecular weight solutes in Ca–alginate gel beads

The elimination or degradation of micropollutants from wastewater is becoming ever more important nowadays. Using oxidoreductase enzymes to treat different micropollutants seems a promising solution. However, the viability of the process is highly dependent on the availability and stability of the applied enzymes. In order to improve the stability and provide faster reaction rates, enzymes can be immobilized in various carriers. Properties such as simple production, easy retention and biodegradable carrier material are advantageous, e.g. entrapping laccase in alginate beads. This paper shows the results of the preparation and characterization of immobilized laccase entrapped in calcium alginate beads. The technique of adding a mixture of sodium alginate and laccase dropwise into calcium chloride has been applied, improved and standardized to produce laccase-containing beads of uniform size and activity. For the purpose of characterization, a widely used substrate, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, was used to evaluate the performance of the laccase-containing alginate beads. In addition to the characterization of the laccase-containing alginate beads, the enzyme kinetic constants (K M = 26.43 µM, Vmax = 0.23 µM/min) were determined. The reduction in the activity during storage has been described by a decay constant (0.26 d −1) that provides information concerning the design constraints of the process. Results will be used to test the method in terms of the removal of organic micropollutants in continuous systems.

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“…In the case of low-molecular-weight compounds, e.g. ABTS, free diffusion can be assumed in the alginate matrix [30].…”

Section: Discussionmentioning

confidence: 99%

Immobilization of Laccase in Alginate Beads

Varga¹,

Meiczinger²,

Somogyi³

2019

Hung. J. Ind. Chem.

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“…Puguan et al [29], Dembczynski and Jankowski [7], and Li et al [23] reported Vitamin B-12 diffusivity of 2.79-2.17 × 10 − 10 m 2 /s in 1.5-3% calcium alginate, 2.27-2.16 × 10 − 10 m 2 /s in 0.5-1% calcium alginate, and 1.74-2.89 × 10 − 10 m 2 /s in 1.5-3% calcium alginate respectively. Vitamin B-12 is mostly introduced into the polymer as part of CaCl 2 solution.…”

Section: Mathematical Modelmentioning

confidence: 98%

“…Different physico-chemical concepts of hindered diffusion e.g., obstruction effects, reduction in free volume of gel, additional hydrodynamic drag on the solute, steric factors, increased path length due to obstruction, and convective flow of liquid due to swelling or shrinkage were considered [1,18,27,30]. Diffusion of several solutes was studied in alginate [12,14,15,20,24,25,29] and chitosan [10,35]. In most of these studies, the diffusivity of solute in the gel matrix was derived from the release profile using a linearized analytical model with assumption of diffusion in the gel matrix as rate limiting, and negligible mass transfer resistance at the interface between gel and release sink.…”

Section: Introductionmentioning

confidence: 99%

Diffusion in and around alginate and chitosan films with embedded sub-millimeter voids

Patra

Bal

Ganguly

2016

Materials Science and Engineering: C

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“…e steviol glycosides have a higher molecular weight than the phenolic compounds, and the values of the constants (K) were lower; this means that steviol glycosides are released slower due to their interaction with the polymer membrane [23].…”

Section: Advances In Materials Science and Engineeringmentioning

confidence: 99%

“…Similarly, BelscakCvitanovic et al [22] conducted a study on the release of phenolic compounds from various plants and observed that all the release profiles conformed to the Fickian diffusion model. Taking these two studies into account, it can be pointed out that phenolic compounds, having a low molecular weight, can easily permeate through the capsules and cannot interact through adsorption or ionic interaction with the encapsulating polymeric material [23].…”

Section: Advances In Materials Science and Engineeringmentioning

confidence: 99%

Release Kinetic Studies of Stevia rebaudiana Extract Capsules from Sodium Alginate and Inulin by Ionotropic Gelation

Martínez

Ruiz

Campos

2018

Advances in Materials Science and Engineering

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is study was oriented towards encapsulation of S. rebaudiana extract and the study of its release kinetics. e desired encapsulation was achieved by the ionotropic gelation method using sodium alginate and inulin of polymeric constituents. Characterization of the capsules was performed by micrometric properties, encapsulation efficiency, in vitro extract release analysis, and biological activity of released extract. e in vitro release profiles from different capsules were applied on different kinetic models. e prepared capsules were found spherical in shape with diameters ranging from 2.07 to 2.63 mm, having the encapsulation efficiencies of 43.77% and 56.53% for phenolic compounds and steviol glycosides, respectively. e best-fit model with the highest correlation coefficient was observed in the Ritger-Peppas model, indicating diffusion controlled principle. e release exponent n value obtained from the Korsmeyer-Peppas model varied between 0.2273 and 1.1719, confirming that the mechanism of S. rebaudiana extract bioactive compounds release was diffusion controlled.

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Diffusion characteristics of different molecular weight solutes in Ca–alginate gel beads

Cited by 37 publications

References 16 publications

Immobilization of Laccase in Alginate Beads

Immobilization of Laccase in Alginate Beads

Diffusion in and around alginate and chitosan films with embedded sub-millimeter voids

Release Kinetic Studies of Stevia rebaudiana Extract Capsules from Sodium Alginate and Inulin by Ionotropic Gelation

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