Carrageenan Beads Research Articles

Fabrication of graphitic carbon nitride/gum Arabic/potassium carrageenan composite for efficient adsorption of erythromycin: Kinetic and thermodynamic studies

Erythromycin (ERY) molecules are robust to the environment and hard to remove due to their aromatic structure. Nowadays, numerous researches have reported that the ERY amount in water is above the standard level and its removal is necessary. Here, we prepared three solid adsorbents: graphitic carbon nitride (g-C3N4), potassium carrageenan beads (Cr), and graphitic carbon nitride/gum Arabic/potassium carrageenan composite (g-ACr). Several techniques such as XRD, SEM, TEM, TGA, ATR-FTIR, Zeta potential, and N2 adsorption were employed to characterize the fabricated adsorbents. Five essential factors of adsorbent dose, initial ERY concentration, contact time, temperature, and pH were optimized to investigate the batch adsorption of ERY. The maximum adsorption capacity of 356.12 mg/g was attained by g-ACr composite at an adsorbent dose of 1.25 g/L, contact time of 6 h, and pH 7 at 15 °C. The data showed that the experimental findings exhibited the best agreement with Langmuir, Temkin, and DR isotherm models, in addition to the kinetic models of pseudo-second-order, Elovich, and intra-particle diffusion. The evaluated thermodynamic factors designated that the ERY adsorption is endothermic, physisorption, favorable, and spontaneous process. The g-ACr reusability displayed a decline in the adsorption capacity after seven adsorption/desorption runs by 5.7 %. Finally, this work outcomes depict that g-ACr composite is an efficient reusable adsorbent for ERY elimination from wastewater.

Cation Effect in Polysaccharide-Based Hydrogel Beads Produced for Europium Adsorption from Aqueous Solutions

In recent decades, renewable and biodegradable polysaccharide-based hydrogels have enjoyed wide applicability among them also as adsorbents for heavy metal removal from wastewaters. Herein we prepared hydrogel beads from iota and kappa carrageenans using a variety of salts as crosslinkers, that were tested for the first time in europium ion (Eu3+) sorption from an aqueous solution as representative lanthanide. The type of the salt, and especially the valance and the hydrated radius of the cation, were found to dictate hydrogel bead formation and structure and, therefore, the Eu3+ sorption yield. The results of ATR-FTIR, SEM and TGA analyses to characterize the iota carrageenan hydrogel beads that were prepared with alkali cations, before and after interaction with Eu3+, indicate that the adsorbent prepared with LiCl was much stiffer and more stable than those prepared with NaCl or KCl. The iota carrageenan beads that were prepared with LiCl were also reused 5 times while exhibiting high adsorption capacities.

Preparation and Characterization of Chitosan coated alginate and carrageenan beads Loaded with Venlafaxine HCl: A Comprehensive Study

This study focuses on the development of microsphere systems for the sustained release of Venlafaxine Hydrochloride (HCl) using the ionotropic gelation method with sodium alginate, chitosan, carrageenan and calcium chloride as key components. The microspheres were characterized for their size, shape, and surface morphology using scanning electron microscopy (SEM). X-ray powder diffraction analysis (X-RD) was employed to determine the physical state of the drug within the formulations, while Fourier-transform infrared spectroscopy (FTIR) was used to investigate the drug-polymer interactions. Additionally, entrapment efficiency, in vitro release, and release kinetics were evaluated.The results of FTIR analysis indicated no significant interactions between the drug and polymers, ensuring the stability of the formulated microspheres. X-RD analysis confirmed the presence of the drug in an amorphous state within the beads, facilitating its sustained release. Furthermore, the absence of significant drug-polymer interactions, as indicated by FTIR analysis, supports the stability and integrity of the formulated beads. In conclusion, the developed microsphere systems demonstrate promising potential for the sustained release of Venlafaxine HCl. Their high entrapment efficiency, controlled release rate, and stability make them viable option for improving the therapeutic efficacy and patient compliance associated with Venlafaxine HCl administration. Further studies are warranted to evaluate their pharmacokinetic and pharmacodynamic profiles, as well as their long-term stability, to ensure their suitability for clinical applications.

Boosting the stability of β-galactosidase immobilized onto soy-protein isolate-glutaraldehyde-functionalized carrageenan beads

Uncontrolled enzyme-immobilizer interactions were evident after immobilizing β-galactosidase onto soy-protein isolate-glutaraldehyde-functionalized carrageenan beads. Such interactions triggered shortcomings in the immobilized β-galactosidase (iβGL) thermal and storage stabilities. The thermal stability of the iβGL was somewhat lesser than that of the free βGL. Moreover, the iβGL suffered an initial sharp fall-off in its activity after storing it. Thus, approaches were adopted to prevent the occurrence of such uncontrolled enzyme-immobilizer interactions, and accordingly, boost the stability of the iβGL. These approaches involved neutralizing the covalently reactive GA entities via glycine and also altering the functionalizing GA concentrations. Nonetheless, no improvement was recorded in the iβGL thermal stability and this indicated that the uncontrolled enzyme-immobilizer interactions were not mediated via GA. Another approach was then attempted which involved treating the iβGL with lactose. The lactose-treated iβGL (LT-iβGL) presented superior thermal stability as was verified from its smaller kd and bigger t1/2 and D-values. The LT-iβGL t1/2 values were 5.60 and 3.53 fold higher than those presented by the free βGL at 62 and 65 °C, respectively. Moreover, the LT- iβGL presented loftier ΔG than did the free βGL. The storage stability of the LT- iβGL was also superior as it offered 100.41% of its commencing activity on its 43rd storage day. Thus, it could be concluded that lactose prevented the uncontrolled enzyme-immobilizer interactions. Finally, advantageous galacto-oligosaccharides (GOS) were prepared via the iβGL. The GOS were then analyzed with mass spectrometry, and it was shown that their degree of polymerization reached up to 7.

Carrageenan gel beads for echinochrome inclusion: Influence of structural features of carrageenan

Carrageenan (CRG) and carrageenan/chitosan (CH) gel beads (CRG/CH) were prepared as a release delivery system for echinochrome A (Ech). According to spectral data, the Ech was dispersed in the polymer matrix, interacted with CRG, was not oxidised, and remained stable after encapsulation in CRG beads. Carrageenan beads containing Ech were coated with CH by layering. The influence of the structural features of CRG on the formation of beads and the beads morphology, swelling behaviour, mucoadhesive properties and drug release were evaluated. The polysaccharide matrices with Ech showed different swelling characteristics depending on the pH of the medium and the structure of the CRG used. The slow drug release from polysaccharide matrixes was observed for κ- and κ/β-CRG beads, that contained 3,6-anhydro-α-d-galactopyranose units and had high molecular weight. The obtained results showed the prospects of using polysaccharide beads to include Ech.

1,3-Di-naphthalimide Conjugate of Calix[4]arene as a Sensitive and Selective Sensor for Trinitrophenol and This Turns Reversible when Hybridized with Carrageenan as Beads.

A fluorescent naphthalimide conjugate of calix[4]arene (L1) has been synthesized and characterized. The selective and efficient detection of trinitrophenol (TNP) by L1 among nine other different nitroaromatic compounds was demonstrated using absorption and fluorescence spectroscopy. The minimum detection limit is 29 nM, which is the lowest reported so far by any conjugate of calixarene toward TNP. The fluorescence quenching is associated with a high Stern–Volmer constant of 3.3 ± 0.4 × 105 M–1. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) data revealed a network structure with pores having a weighted average size of 0.66 ± 0.08 μm for L1. When incubated with TNP, the pores were filled with fibril structures, as supported by both SEM and TEM data. In order to demonstrate the real time applications, the L1 has been coated onto a Whatman filter paper and the imprint of TNP contaminated thumb has been detected upon physical contact. The 1HNMR titration and the studies carried out using the control molecule support the necessity of both the naphthalimide moiety and the calixarene platform for sensing. In order to mend L1 as a reversible sensor for TNP, the same is incorporated into carrageenan beads (L1@Cb) and the reversible sensing has been shown for three cycles by reusing the same material upon recovery followed by washing it. The solid-state detection of TNP has also been demonstrated using the lyophilized L1@Cb bead powder. The fluorescence intensity of L1 was quenched upon addition of solid TNP to the lyophilized bead powder of L1@Cb as studied by fluorescence microscopy. The computational studies show that one of the arms of the calixarene takes a bent conformation, and the 1:1 TNP complex of L1 is stabilized by exhibiting differential extents of hydrogen bonding interactions with the two arms owing to their conformational difference. The result of such complexation was already felt through the shifts observed in the experimentally measured 1HNMR spectra.

Biotransformation of ginsenoside using covalently immobilized snailase enzyme onto activated carrageenan gel beads

Ginsenoside transformation has received significant attention from scientists. The main objective of this study is to use immobilized enzymes in ginsenoside transformation. Factors affecting immobilization process were studied; carrageenan beads treated with polyethyleneimine and then activated using glutaraldehyde (GA) were used for snailase enzyme immobilization. The functionalized gel beads were characterized using Fourier transform infrared spectroscopy to verify the modification process. Furthermore, the optimum conditions for biotransformation of ginsenoside were also deliberated and showed that optimum biotransformation pH is 4.5 and 5–5.5 and temperature 50 and \(60^{\circ }\hbox {C}\) for free and immobilized snailase, respectively. Michaelis constants, \(K_{\mathrm{m}}\) and \(V_{\max }\), were also studied. The immobilized enzyme retains 96% of its initial activity after being used 10 consecutive times. The results clearly suggested that ginsenoside transformation was performed using immobilized snailase; this process can reduce the transformation cost as the enzyme can be reused many times.

Adsorption of Fe ions by modified carrageenan beads with tricarboxy cellulose: kinetics study and four isotherm models

Adsorption of Fe ions by modified carrageenan beads with tricarboxy cellulose: kinetics study and four isotherm models

Development of carrageenan modified with nanocellulose-based materials in removing of Cu2+, Pb2+, Ca2+, Mg2+, and Fe2+

Different bio-polymeric matrixes of carrageenan and modified carrageenan with cellulosic nonmaterials were prepared in the form of beads. The nanocellulosic materials were prepared from dissolved bagasse pulp and include cellulose nanocrystals, cellulose nanofibers and tricarboxy cellulose nanofibers. The prepared bio-polymeric matrixes were characterized with transmission electron microscopy, FTIR, X-ray diffraction and scanning electron microscope. The capabilities of carrageenan and modified carrageenan beads to chelate with several metal cations were evaluated. Interestingly, the modification of carrageenan with cellulose nanoparticles obtained high efficiency toward removing Cu2+, Pb2+, Ca2+, Mg2+, and Fe2+. The modified carrageenan with tricarboxy cellulose nanofibers which has higher carboxylate content showed high removal efficiency rather than the other modifications.

Controlling lipid digestion profiles using mixtures of different types of microgel: Alginate beads and carrageenan beads

For certain applications, it is useful to control the rate and extent of lipid digestion in different regions of the gastrointestinal tract (GIT) e.g., to control bioavailability, satiety, or blood lipid levels. In the current study, lipid digestion was modulated by mixing two kinds of lipid-loaded biopolymer microgels (alginate beads and carrageenan beads) with different GIT responses. The microgels were formed by mixing lipid droplets with anionic polysaccharide solutions, and then injecting them into a calcium ion solution to cross-link the polysaccharides. Alginate beads remained intact throughout the GIT, leading to a relatively slow digestion rate, whereas carrageenan beads became deformed and dissociated, leading to faster digestion. Experiments using an in vitro GIT model indicated that the rate of lipid digestion could be controlled by mixing alginate microgels with carrageenan microgels. The rate of lipid digestion of the mixed system (1:1) was between that of the two individual systems. These mixed microgel systems may be useful in developing functional foods that modulate lipid blood levels, hormone release, and energy intake.

Whey protein isolate for the preparation of covalent immobilization beads

Whey protein isolate (WPI) was employed, for the first time, to activate carrageenan (Car) beads for the covalent immobilization of the Aspergillus oryzae β-D-galactosidase (β-gal). These Car beads were subjected to a WPI treatment step followed by a glutaraldehyde (GA) treatment step in order to enable such covalent immobilization. The WPI treatment was optimized via the Box-Behnken Design (BBD). The BBD anticipated that treating the Car beads with a 2.36% WPI solution of pH 5.25 for 7.04 h would allow for the attainment of an immobilized β-gal's activity recovery percent of 34.43%. A verification experiment was accomplished while employing the abovementioned conditions and an immobilized β-gal's activity recovery percent of 34.80 ± 1.11% was attained. It was also shown that the immobilization of β-gal onto the GA-WPI treated Car beads did not alter the enzyme's optimum temperature or optimum pH. Moreover, a reusability study was conducted and 93.84 ± 0.72% of the immobilized β-gal's initial observed activity was preserved during the 13th reusability cycle.

Stability Studies of Immobilized Saccharomyces Cerevisiae in Calcium Alginate and Carrageenan Beads

Currently the resources for fossil fuels are depleting together with increase in fuel prices. This has urged the need for cheaper alternative fuels especially biofuels. The production of the most common liquid biofuel which is bioethanol using immobilized yeast cells is an approach taken to increase its demand in the world’s market. There are various methods for the immobilization of yeast cells; however before they can be applied in the industry the stability of the immobilization technology must be investigated. This research aims to study the stabilities of immobilized S. cerevisiae in calcium alginate and carrageenan beads for bioethanol production. The S. cerevisiae was immobilized in calcium alginate and carrageenan beads using entrapment method. Next, screening for the optimal concentration of sodium alginate and semi refined carrageenan matrices were determined by employing fermentation and bioethanol quantification using GC-MS. Concentrations of 2% (w/v) calcium alginate and 2% (w/v) semi refined carrageenan beads were identified to produce the highest bioethanol yield which were 0.286 g/mL and 0.065 g/mL respectively. The two beads were then chosen to be tested in various stability studies with respect to bioethanol production such as storage stability, reusability, pH, thermaland permeability test. It was found out that a concentration of 2% (w/v) calcium alginate beads were more stable as immobilization matrix for S. cerevisiae as compared to 2% (w/v) semi refined carrageenan.

Covalent immobilization of cellulase in application of biotransformation of ginsenoside Rb1

Cellulase was immobilized on the surface of carrageenan beads activated by using polyethyleneimine and glutaraldehyde, then immobilized cellulase was used to transform ginsenoside Rb1. In this work, we studied the functionalization of carrageenan with amine terminal functional group for the covalent immobilization of cellulase. The process of immobilization was performed by amination process on the surface of the carrageenan gel beads with polyethylenimine followed by activation with glutaraldehyde to finally immobilize the enzyme. Different factors affecting the amination and activation processes were studied and their effects on the catalytic activity of the immobilized cellulase were followed, then Fourier transform infrared spectroscopy and scanning electron microscopy were applied to verify the process. Furthermore, the optimum conditions of transformation of ginsenoside Rb1 were also studied and showed better stability for the immobilized enzyme. The best results were obtained using carrageenan as support and covalent binding method, which consisted of amination process (0.5% PEI (pH 8))) for 3h and 3% GA in activation process for 3h. These experiments gave optimum reaction condition of temperature at 60°C and pH 5.0. Enzyme after immobilization exhibited high activity with broader pH and temperature range. Full conversion and kinetic parameters Km and Vmax for them were also studied. The Km of immobilized enzyme, 3.64mM, is lower than free one, 4.82mM; and the Vmax of immobilized enzyme, 0.04mM, is lower than free one, 0.06mM. Results detected also show after using for 5 consecutive times, the immobilized enzyme can retain 60% of its initial activity.

Encapsulation of curcumin in polysaccharide-based hydrogel beads: Impact of bead type on lipid digestion and curcumin bioaccessibility

Curcumin was incorporated into three different delivery systems: free lipid droplets; lipid-loaded alginate beads; and, lipid-loaded carrageenan beads. Hydrogel beads were fabricated from polysaccharides (alginate or carrageenan) using an injection method combined with ion gelation (calcium or potassium, respectively). The delivery systems were passed through a simulated gastrointestinal tract (GIT) that included mouth, stomach, and small intestine phases. Light scattering and microscopy indicated that carrageenan beads had a relatively fragile structure that was easily disrupted in the GIT and released the encapsulated lipid droplets and curcumin. Conversely, alginate beads had a robust structure that remained relatively intact throughout the GIT and retained the lipid droplets and curcumin. The rate and extent of lipid digestion decreased in the following order: free lipid droplets > carrageenan beads > alginate beads. Curcumin bioaccessibility followed a similar order: free lipid droplets (73%) > carrageenan beads (33%) > alginate beads (16%). These results suggest that lipid droplets must be digested by lipase in order to release the encapsulated curcumin and to form mixed micelles capable of solubilizing the released curcumin. Overall, our results show that delivery systems with different structures and compositions can be designed to control the release of lipids and hydrophobic nutraceuticals in the GIT, which may be advantageous for the development of certain functional food products.

Encapsulation of lactase (β-galactosidase) into κ-carrageenan-based hydrogel beads: Impact of environmental conditions on enzyme activity

Encapsulation of enzymes in hydrogel beads may improve their utilization and activity in foods. In this study, the potential of carrageenan hydrogel beads for encapsulating β-galactosidase was investigated. Hydrogel beads were fabricated by injecting an aqueous solution, containing β-galactosidase (26U) and carrageenan (1wt%), into a hardening solution (5% potassium chloride). Around 63% of the β-galactosidase was initially encapsulated in the hydrogel beads. Encapsulated β-galactosidase had a higher activity than that of the free enzyme over a range of pH and thermal conditions, which was attributed to the stabilization of the enzyme structure by K+ ions within the carrageenan beads. Release of the enzyme from the beads was observed during storage in aqueous solutions, which was attributed to the relatively large pore size of the hydrogel matrix. Our results suggest that carrageenan hydrogel beads may be useful encapsulation systems, but further work is needed to inhibit enzyme leakage.

Application of Plackett–Burman screening design to the modeling of grafted alginate–carrageenan beads for the immobilization of penicillin G acylase

ABSTRACTGrafted alginate–carrageenan beads were used to immobilize the industrial enzyme penicillin G acylase (PGA). Sixteen factors were screened with the Plackett–Burman design (PBD) to test their significance on the gel beads formation and enzyme immobilization process. The results of PBD showed a wide variation of 30‐fold in the amount of immobilized penicillin G acylase (iPGA) from 11.9 to 354.16 U/g of beads; this reflected the importance of the optimizing process. Among the 16 tested factors, only 3 were proven to be significant. These factors were the enzyme buffer pH (N), enzyme soaking time (Q) with the gel beads, and enzyme concentration (P). The Pareto chart revealed that both Q and P exerted significant positive effects on the amount of iPGA, whereas N had a negative effect. We recommend further study to optimize only these three significant, distinctive enzyme factors. The PGA covalent attachment to the gel beads were proven by Fourier transform infrared spectroscopy, elemental analysis, and NaCl and reusability tests. The best gel bead formula succeeded in the immobilization of 354.16 U/g of beads and proved to be reusable 14 times, retaining 84% of the initial enzyme activity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40295.

Kappa-Carrageenan beads as new adsorbent to remove crystal violet dye from water: adsorption kinetics and isotherm

K+-Cross-linked kappa-Carrageenan beads were prepared and the dried and wet beads of cross-linked carrageenan were evaluated to remove the cationic crystal violet (CV) dye from water. The kinetics and mechanism of CV adsorption onto both wet and dried carrageenan beads were studied. The effect of contacting time and initial concentration of CV on adsorption was investigated. It was revealed that the rate of dye adsorption and removal efficiency is higher for the wet carrageenan beads. The experimental adsorption data were modeled using pseudo-first-order, pseudo-second-order, and Boyd models. The results showed that the pseudo-second-order adsorption kinetics were predominated for the adsorption of CV onto carrageenan beads. The experimental equilibrated adsorption capacity of carrageenan beads was analyzed using Freundlich and Langmuir isotherm models. The results corroborated that the experimental data followed the Freundlich isotherm the best. No significant change in dye adsorption onto beads was observed by varying the pH of initial dye solution.

Comparative studies on physico-chemical characterization of yeast cells entrapped with alginate and hybrid beads

Natural polymers used as carrier materials in immobilization technology have the advantage of being non-toxic, biocompatible and biodegradable. In the present investigation, immobilization of yeast cells using different polymers has been carried out and the properties such as morphological, hardening, thermal stability and characterization of functional groups of alginate and hybrid beads (alginate–carrageenan and alginate–xanthan gum) have been studied by different techniques such as scanning electron microscope, texture analyzer, differential scanning calorimetry, and Fourier transfer infrared spectroscopy. The swelling behavior in terms of pH variation as well as flow properties of alginate and hybrid beads has also been examined. The hybrid beads prepared from alginate and carrageenan were found to be the best in terms of strength, cell holding capacity, pH and thermal stability. The reusability of beads was also studied in terms of enzyme activity of the entrapped yeast cells. The beads prepared by alginate–carrageenan were found to be more stable than alginate and alginate–xanthan beads. The yeast cells entrapped in alginate–carrageenan beads showed no significant decrease in enzyme activity up to seven batches. Thus, alginate–carrageenan beads can be used as a polymeric carrier/support to develop a stable and long-term immobilized cell system, which indicates its high potential for commercial applications in food and pharmaceutical sector.

Comparison of some biochemical properties of artichoke polyphenol oxidase entrapped in alginate-carrageenan and alginate gels

Polyphenol oxidase (PPO, EC.1.14.18.1) isolated from artichoke (Cynara scolymus) was entrapped within alginate and alginate+ carrageenan beads, and the catecholase and cresolase activities of both entrapped enzymes were determined. Some properties of these immobilized enzymes such as optimum pH and temperature, kinetic parameters (Km and Vmax), thermal, and storage stability were determined and compared to each other.The highest catecholase activity was observed in alginate gel (370 U/g bead) while the highest cresolase activity was in alginate+ carrageenan gel (90 U/g bead). For catecholase and cresolase activities, optimum pHs of alginate and alginate+ carrageenan beads were determined to be 7.0 and 4.0, respectively. Optimum temperatures for catecholase activity were determined to be 40°C for both entrapped enzymes. These values for cresolase activity were 30°C and 20°C, respectively. Immobilized artichoke PPOs greatly preserved their thermal stability which exists anyway. The catalytic efficiency value (Vmax/Km) of the alginate beads is approximately high as two-and-a-half folds of that of alginate+κ-carrageenan beads for cresolase activity. These values were very close for catecholase activity. Immobilized beads saved their both activities after 30 days of storage at 4°C.

PREPARATION AND PHYSICOCHEMICAL EVALUATION OF BIODEGRADABLE MAGNETIC Κ-CARRAGEENAN BEADS AND APPLICATION FOR CHROMIUM IONS PRE-CONCENTRATION

This study aims to examine the ability of magnetic Қ-carrageenan beads as an adsorbent in solid phase extraction towards chromium ions from aqueous solution. In this study, Қ-carrageenan magnetic gel-beads were obtained via interphase technique. The beads were kept in 0.3 M KCl to maintain gel strength. Physicochemical of the resulting materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and magnetometer. FTIR results have confirmed the presence of functional groups such as sulphate esters groups. The diameter of carrageenan beads was about ~764 μm where SEM micrographs showed the spherical formed shape of carrageenan beads and a rough surface with pores. The saturation magnetization value, M c , of carrageenan beads in this study was 18.78 EMU/g. The magnetic function of carrageenan beads is to facilitate bead collection and to get the Cr6+ ion that adsorbed onto the beads. The adsorption of chromium ions by magnetic carrageenan beads are through an ion exchange mechanism and formation of metal-ligand complex. Optimal timing for adsorption of chromium ions was at 60th minute. The optimal operation conditions can be achieved on pH value~1 and concentration of 100 ppm. Langmuir adsorption isotherm curve for Cr6+ is similar to Langmuir adsorption isotherm types III (unfavorable).