Bead Formulations Research Articles

Formulation and evaluation of hydrocortisone micro beads

The current study aimed to develop hydrocortisone mucoadhesive microbeads to prolong the drug's action in the gastrointestinal system, targeting Crohn's disease treatment. Hydrocortisone, known for its anti-inflammatory and anti-rheumatic effects, was utilized in bead form to enhance therapeutic efficacy, extend residence time, and reduce dosage frequency. Using sodium alginate, HPMC, and Eudragit L-100 as adhesive polymers, and calcium chloride and aluminium chloride as cross-linking agents, the study crafted microbeads with an entrapment efficiency between 57.23% and 91.69%. Evaluations focused on in vitro drug release, particle size, surface characteristics, entrapment efficiency, and the role of cross-linking ions. Of the formulations, HCS-8 (with sodium alginate and Eudragit L-100 using aluminium chloride as the gelling solution) and HCS-2 showed optimal drug release profiles. Notably, HCS-8 achieved a 12-hour drug release delay, attributed to aluminium chloride's cross-linking action. Drug release kinetics revealed a zero-order linearity (R2=0.99), suggesting super case 2 transport as the primary release mechanism.

Losartan potassium-loaded linseed polysaccharide-alginate-calcium silicate biomucoadhesive-floating beads for gastroretentive delivery

ABSTRACT The current research presents the formulation of losartan potassium-loaded biomucoadhesive-floating beads using sodium alginate (matrix-former), linseed polysaccharide (biomucoadhesive polymer) and calcium silicate (floatation-improving material). These losartan potassium-loaded beads showed 63.86 ± 0.93 to 95.33 ± 2.14% drug entrapment efficiency, 1.44 ± 0.04 to 1.72 ± 0.08 mm bead-size and 0.65 ± 0.06 to 0.81 ± 0.06 g/cm3 density. The biomucoadhesive-floating beads were characterized by SEM, FTIR and p-XRD. In gastric pH, losartan potassium-loaded beads presented excellent buoyancy, in vitro drug releasing over 10 h and good biomucoadhesivity. These biomucoadhesive-floating beads could be profitable to prolong gastroretention with sustained drug releasing.

PAN/PVP/CD-MOF Composite Beads for the Removal of Methylene Blue and Congo Red in Water

Cyclodextrin metal-organic frameworks (CD-MOFs) are synthesized from green precursors, making them an ideal material for green adsorbents. However, CD-MOFs are unstable in water, thus limiting their applications. Here, we report encapsulating CD-MOFs in polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) polymeric support to produce PAN/PVP/CD-MOF composite beads. Batch adsorption studies showed that high dye adsorption capacities could be obtained at intermediate PVP, high PAN, and low CD-MOF loadings. Maximum MB and CR sorption capacities under optimum bead formulation: PAN = 6.96 wt.%, PVP = 2.20 wt.%, and CD-MOF = 2.88 wt.%. The optimized composite beads have a sorption capacity of 37.40 mg/g for MB and 18.42 mg/g for CR. We showed that PAN/PVP/CD-MOF composite beads could be an excellent adsorbent for textile dye removal in water.

The optimization of poly(vinyl)-alcohol-alginate beads with a slow-release compound for the aerobic cometabolism of chlorinated aliphatic hydrocarbons.

Chlorinated aliphatic hydrocarbons (CAHs), such as cis-1,2-dichloroethylene (cDCE), are prevalent in groundwater at many locations throughout the United States. When immobilized in hydrogel beads with slow-release compounds, the bacteria strain Rhodococcus rhodochrous ATCC 21198 can be used for the in situ bioremediation of cDCE. These hydrogel beads must exhibit high mechanical strength and resist degradation to extend the lifetime of slow-release compounds and bioremediation. We engineered poly(vinyl)-alcohol - alginate (PVA-AG) beads to immobilize ATCC 21198 with the slow-release compound, tetrabutoxysilane (TBOS) that produces 1-butanol as a growth substrate, for high mechanical strength. We optimized three inputs (concentration of PVA, concentration of AG, and the crosslinking time) on two responses (compressive modulus and rate of oxygen utilization) for batch incubation experiments between 1 and 30 days using a design of experiments approach. The predictive models generated from design of experiments were then tested by measuring the compressive strength, oxygen utilization, and abiotic rates of hydrolysis for a predicted optimal bead formulation. The result of this study generated a hydrogel bead with immobilized R. rhodochrous ATCC 21198 and TBOS that exhibited a high compressive modulus on day 1 and day 30, which was accurately predicted by models. These hydrogel beads exhibited low metabolic activity based on oxygen rates on day 1 and day 30 but were not accurately predicted by the models. In addition, the ratio between oxygen utilization and abiotic rates of hydrolysis were observed to be roughly half of what was expected stoichiometrically. Lastly, we demonstrated the capability to use these beads as a bioremediation technology for cDCE as we found that, for all bead formulations, cDCE was significantly reduced after 30 days. Altogether, this work demonstrates the capability to capture and enhance the material properties of the complex hydrogel beads with predictive models yet signals the need for more robust methods to understand the metabolic activity that occurs in the hydrogel beads.

Extraction of dietary fiber and encapsulated phytochemical enriched functional pasta from Bottle gourd (Lagenaria siceraria) peel waste

Bottle gourd (Lagenaria siceraria) peels are treated as an agro-waste material and are generally discarded. Dietary fiber and phytochemicals from this agro-waste material can serve as important functional ingredients. The aim of this study was to utilize bottle gourd peels for extraction of dietary fiber and phytochemicals and use them as functional ingredients in the preparing pasta. Dietary fiber was extracted using alkaline extraction (AEDF), ultrasound-assisted alkaline extraction (UAEDF) and enzymatic extraction (EADF). The optimised conditions for extraction using ultrasound-assisted alkaline extraction were 1: 60 solute to solvent ratio, 40 min sonication time, and 40 % ultrasonic amplitude. The physicochemical and functional properties of extracted dietary fiber, results showed that dietary fiber from ultrasound-assisted alkaline extraction gave a better result for thermal, oil and water holding properties. Phytochemicals were extracted and identified using RP-HPLC followed by encapsulation using 2 % sodium alginate solution as the wall material. Functional pasta was prepared by incorporation of extracted dietary fiber and encapsulated phytochemicals in 5 different formulations of durum wheat semolina (g), extracted DF (g) and phytochemical beads (mg). The results of the study revealed that bottle gourd peel could be used as an inexpensive source of dietary fiber and phytochemicals to prepare functional foods.

Encapsulation of pomegranate polyphenols by ionic gelation: Strategies for improved retention and controlled release

This study aimed at producing pectin hydrogel beads by ionic gelation proce to carry pomegranate extract (PE) evaluating approaches to increase its retention and protect the polyphenols from environmental conditions that interfere in the stability and color of these compounds, such as the pH of the medium. Several strategies were tested to reduce the mass transfer and consequently increase its retention. The insertion of a filler (gelatinized starch), the employment of different concentrations from the external environment, the adsorption using blank pectin-starch beads, and the electrostatic coating using chitosan were performed. The release of entrapped compounds over time was employed to evaluate the release pattern of PE in water media. Diffusion coefficients calculated from these experiments were then used to estimate the PE release behavior. The encapsulation efficiency (EE) was significantly improved (42 % to 101 %) when equalizing the concentration of the external medium with that from the beads formulation. Furthermore, the increase in the PE concentration was proportional to the rise in the mechanical strength (MS) of the beads which indicates a modification of internal structure due to the presence of polyphenols. The adsorption was efficient in entrapping the active compound, and despite the high PE content observed for all beads (average value of 2960.26 mg of gallic acid equivalent/100 g sample), they had the lowest diffusion coefficient from the release in water media. Finally, the coating was able to reduce the release rate in most of the tests (DAB uncoated = 0.5 DAB coated), however, during the electrostatic deposition a loss of about 32 % of the phenolic compounds in the chitosan solution was observed which led to a reduced EE. Despite the obtention of retarded release, coating studies need to be improved. Some adjustments in the execution of this technique are necessary so that the losses are reduced and the process becomes viable for the use of beads in food.

Optimization and Characterization of Sodium Alginate Beads Providing Extended Release for Antidiabetic Drugs.

The current research is aimed at investigating the relationship between the formulation components and conditions in the case of a binary drug delivery system, where antidiabetic drugs are co-formulated into polymeric micelles embedded in sodium alginate. Compared to chemical modifications of polymers with alginate, our development provides a simpler and scalable formulation process. Our results prove that a multi-level factorial design-based approach can ensure the development of a value-added polymeric micelle formulation with an average micelle size of 123.6 ± 3.1 nm and a monodisperse size distribution, showing a polydispersity index value of 0.215 ± 0.021. The proper nanoparticles were co-formulated with sodium alginate as a biologically decomposing and safe-to-administer biopolymer. The Box-Behnken factorial design ensured proper design space development, where the optimal sodium alginate bead formulation had a uniform, extended-release drug release mechanism similar to commercially available tablet preparations. The main conclusion is that the rapid-burst-like drug release can be hindered via the embedment of nanocarriers into biopolymeric matrices. The thermally stable formulation also holds the benefit of uniform active substance distribution after freeze-drying.

Formulation and Evaluation of Mucoadhesive Beads of Dexamethasone

The goal of the current study was to formulate and evaluate mucoadhesive Dexamethasone beads to significantly lengthen the duration of the drug's stay in the GI system to treat Crohn’s disease. Dexamethasone is a corticosteroid that acts as an anti-rheumatic and anti-inflammatory. To decrease the dosage frequency Dexamethasone adhesive beads were formulated for Intimate contact with the underlying absorption surface is made possible by a prolonged stay at the location, which enhances the drug's therapeutic effectiveness. In the current study, calcium chloride and aluminium chloride were utilised as cross-linking agents to create Dexamethasone mucoadhesive beads employing adhesive polymers like sodium alginate, HPMC, and Eudragit L-100. The prepared beads' entrapment efficiencies ranged from 57.15 to 99.16%. Regarding entrapment effectiveness, particle size, surface properties, and in-vitro drug release experiments, the impact of bioadhesive polymers and cross-linking ions was assessed. The MPS-7 delayed the drug's release for 12 hours, which may be related to the cross-linking agent aluminium chloride. According to drug release kinetics, all of the formulations were more linear concerning zero order (r2=0.99) than concerning first order (r2=0.751 to 0.828). Super Case 2 Transport was discovered to be the precise release mechanism.

Formulation and Evaluation of Micro Beads of Clonidine for the Treatment of Anxiety and Hypertensive Disorder

A chronic medical condition known as hypertension (HT) is characterised by persistently high blood pressure (BP) in the arteries. Although HT is initially asymptomatic, it eventually develops into a significant risk factor for renal, cardiovascular, and cerebrovascular conditions, which in turn are major contributors to morbidity and mortality in industrialised nations. A complicated disorder called HT is thought to affect more than one-fourth of adult humans worldwide. Both its pathophysiology (primary and secondary HT) and the measurements of the resting blood pressure (elevated systolic, diastolic, and pulse pressure) are used to categories it. It results from a complex interplay between genes and a number of environmental risk factors, including as ageing, smoking, inactivity, being overweight or obese, eating too much salt, stress, depression, and anxiety. Millions of people are affected by anxiety and depressive disorders each year, which are the most often diagnosed mental illnesses. These conditions are both characterised by emotional, cognitive, psychomotor, and neurovegetative symptoms. Additionally, stress at work has been identified as a significant risk factor for heart disease (CVD) and HT. Despite the fact that numerous writers have looked into and proposed connections between HT, stress, anxiety, and depression over the past few decades, a complete knowledge of the underlying pathophysiological mechanisms has not yet been attained, particularly with regards to young people. The purpose of this study was to examine the role that stress and anxiety from the workplace play in the HT development of young students of health care professions as well as any potential links to early CVDs.
 Keywords: Blood pressure, Anxiety, Work-related stress, Students, Health care professions, Health promotion, Workplace, Occupational medicine

Optimization of sodium alginate-galactoxyloglucan blended hydrogel beads through ionotropic gelation method

Hydrogels are 3D crosslinking networks of hydrophilic biopolymers which can able to absorb and retain large amount of water. In this present study, the Sodium alginate (SA)- Galactoxyloglucan (GXG) blended hydrogel beads were prepared and optimized through two level optimization steps. Alginate and xyloglucan are the cell wall polysaccharides biopolymers obtained from the plant sources, Sargassum sp. and Tamarindus indica L. respectively. The extracted biopolymers were confirmed and characterized by UV-Spectroscopy, FT-IR, NMR and TGA analysis. Based on the hydrophilicity, non-toxicity and biocompatibility, SA-GXG hydrogel were prepared and optimized through two-level optimization steps. The optimized hydrogel bead formulation was characterized through FT-IR, TGA and SEM analysis. From the obtained result, it is found that the polymeric formulation GXG (2 % w/v)-SA (1.5 % w/v), cross-linker (CaCl2) concentration at 0.1 M and the cross-linking time at 15 Min showed significant swelling index. The optimized hydrogel beads are porous and show good swelling capacity and thermal stability. The optimized protocol of hydrogel beads may be useful in designing hydrogel beads for specific applications in agricultural, Biomedical and remediation sectors.

Optimization and In Vitro Characterization of Telmisartan Loaded Sodium Alginate Beads and Its In Vivo Efficacy Investigation in Hypertensive Induced Animal Model.

Antihypertensive drug telmisartan (TEL) belongs to BCS class II, which is characterized by low water solubility and, consequently, low oral bioavailability. Gastroretentive systems may overcome the problems associated with low solubility of TEL and incomplete absorption by localizing the drug release in the stomach. The purpose of this study was to prepare TEL-loaded, oil-entrapped, floating alginate beads with the intent of enhancing the oral bioavailability of TEL for the treatment of hypertension. For the formulation and optimization of seventeen formulations of TEL-loaded oil-entrapped floating alginate beads, a central composite design was utilized. The concentration of sodium alginate (X1), the concentration of cross-linker (X2), and the concentration of sesame oil (X3) served as independent variables, whereas the entrapment efficiency (Y1), in vitro buoyancy (Y2), and drug release Q6h (Y3) served as dependent variables. Using the emulsion gelation method and calcium chloride as the cross-linking agent, different formulations of TEL alginate beads were produced. All formulations were evaluated for their entrapment efficiency percentage, in vitro buoyancy, and in vitro drug release. The optimal formulation of TEL alginate beads was prepared with and without oil and evaluated for entrapment efficiency percentage, in vitro buoyancy, swelling ratio, average size, and in vitro drug release. Using scanning electron microscopes, the surface morphology was determined. Using IR spectroscopy, the compatibility between the ingredients was determined. In vivo evaluation of the optimized formulation in comparison to the free TEL was done in hypertension-induced rats, and the systolic blood pressure and all pharmacokinetic parameters were measured. The prepared beads exhibited a high entrapment efficiency percentage, in vitro buoyancy, and prolonged drug release. TEL was compatible with other ingredients, as approved by IR spectroscopy. The prepared TEL beads were spherical, as shown by the SEM. The relative bioavailability of TEL-loaded oil-entrapped beads was 222.52%, which was higher than that of the pure TEL suspension. The prepared TEL beads formulation exhibited a higher antihypertensive effect for a prolonged time compared to pure TEL suspension. It can be concluded that this innovative delivery method of TEL-loaded oil-entrapped beads is a promising tool for enhancing drug solubility and, thus, oral bioavailability and therapeutic efficacy, resulting in enhanced patient compliance. Furthermore, the in vivo study confirmed the formulation's extended anti-hypertensive activity in animal models.

Design and Optimization of a Nanoparticulate Pore Former as a Multifunctional Coating Excipient for pH Transition-Independent Controlled Release of Weakly Basic Drugs for Oral Drug Delivery.

Bioavailability of weakly basic drugs may be disrupted by dramatic pH changes or unexpected pH alterations in the gastrointestinal tract. Conventional organic acids or enteric coating polymers cannot address this problem adequately because they leach out or dissolve prematurely, especially during controlled release applications. Thus, a non-leachable, multifunctional terpolymer nanoparticle (TPN) made of cross-linked poly(methacrylic acid) (PMAA)-polysorbate 80-grafted-starch (PMAA-PS 80-g-St) was proposed to provide pH transition-independent release of a weakly basic drug, verapamil HCl (VER), by a rationally designed bilayer-coated controlled release bead formulation. The pH-responsive PMAA and cross-linker content in the TPN was first optimized to achieve the largest possible increase in medium uptake alongside the smallest decrease in drug release rate at pH 6.8, relative to pH 1.2. Such TPNs maintained an acidic microenvironmental pH (pHm) when loaded in ethylcellulose (EC) films, as measured using pH-indicating dyes. Further studies of formulations revealed that with the 1:2 VER:TPN ratio and 19% coating weight gain, bilayer-coated beads maintained a constant release rate over the pH transition and exhibited extended release up to 18 h. These results demonstrated that the multifunctional TPN as a pHm modifier and pH-dependent pore former could overcome the severe pH-dependent solubility of weakly basic drugs.

Bead-jet printing enabled sparse mesenchymal stem cell patterning augments skeletal muscle and hair follicle regeneration

Transplantation of mesenchymal stem cells (MSCs) holds promise to repair severe traumatic injuries. However, current transplantation practices limit the potential of this technique, either by losing the viable MSCs or reducing the performance of resident MSCs. Herein, we design a “bead-jet” printer, specialized for high-throughput intra-operative formulation and printing of MSCs-laden Matrigel beads. We show that high-density encapsulation of MSCs in Matrigel beads is able to augment MSC function, increasing MSC proliferation, migration, and extracellular vesicle production, compared with low-density bead or high-density bulk encapsulation of the equivalent number of MSCs. We find that the high-density MSCs-laden beads in sparse patterns demonstrate significantly improved therapeutic performance, by regenerating skeletal muscles approaching native-like cell density with reduced fibrosis, and regenerating skin with hair follicle growth and increased dermis thickness. MSC proliferation within 1-week post-transplantation and differentiation at 3 − 4 weeks post-transplantation are suggested to contribute therapy augmentation. We expect this “bead-jet” printing system to strengthen the potential of MSC transplantation.

Development of calcium alginate beads containing paclitaxel-loaded lipid-core nanocapsules intended for oral administration

We developed a solid formulation of calcium alginate beads containing paclitaxel-loaded lipid-core nanocapsules (PTX-LNC-Bead) intended for oral administration. The PTX-LNC liquid formulation was prepared by interfacial deposition and trapped into calcium alginate beads. These beads were characterized in terms of size, morphology, swelling rate, encapsulation efficiency, and release of PTX and LNC in simulated gastrointestinal fluids. Results showed that the beads were gastro-resistant with low swelling rate and drug release lower than 3.5% at pH 1.2 (2h). At pH 6.8, the beads showed high swelling rate and disintegration after 80 min. Drug release was 60% after 600 min. Particle sizing as a function of time confirmed that LNC were released intact from the beads at pH 6.8 showing that PTX-LNC-Bead is a promising product for PTX oral administration. Our results pave the way for novel formulations intended for drug targeting by the oral route.

Effects of Formulation on the Palatability and Efficacy of In-Feed Praziquantel Medications for Marine Finfish Aquaculture.

Praziquantel (PZQ) provides an effective treatment against monogenean parasitic infestations in finfish. However, its use as an in-feed treatment is challenging due to palatability issues. In this study, five formulations of PZQ beads (1–4 mm) were developed using marine-based polymers, with allicin added as a flavouring agent. All formulations attained PZQ loading rates ≥74% w/w, and the beads were successfully incorporated into fish feed pellets at an active dietary inclusion level of 10 g/kg. When tested for palatability and digestibility in small yellowtail kingfish, the PZQ-loaded beads produced with alginate-chitosan, alginate-Cremophor® RH40, and agar as carriers resulted in high consumption rates of 99–100% with no digesta or evidence of beads in the gastrointestinal tract (GIT) of fish fed with diets containing either formulation. Two formulations produced using chitosan-based carriers resulted in lower consumption rates of 68–75%, with undigested and partly digested beads found in the fish GIT 3 h post feeding. The PZQ-loaded alginate-chitosan and agar beads also showed good palatability in large (≥2 kg) yellowtail kingfish infected with gill parasites and were efficacious in removing the parasites from the fish, achieving >90% reduction in mean abundance relative to control fish (p < 0.001). The two effective formulations were stable upon storage at ambient temperature for up to 18 months, showing residual drug content >90% compared with baseline levels. Overall, the palatability, efficacy and stability data collected from this study suggest that these two PZQ particulate formulations have potential applications as in-feed anti-parasitic medications for the yellowtail kingfish farming industry.

Mechanical properties of gellan gum beads prepared with potassium or calcium ions.

Biopolymer beads can be used as carrier and encapsulation system for a wide variety of materials in food, medical, pharmaceutical, cosmetics, agricultural, and environmental applications. Beads of low acyl gellan gum (0.4-1.2% w/w) were produced using extrusion technique (dripping) followed by an ionotropic gelation step with calcium or potassium chloride. In this methodology, gel formation is accomplished by cations diffusion at room temperature and, as a consequence, different structure and gel properties could be obtained. Gellan beads were subjected to uniaxial compression measurements. The force-displacement curves showed that the occurrence of structural failure under tested conditions depended on beads formulation and was only observed at polysaccharide concentration above 0.8% (w/w). Maximum force or force at failure was mainly dependent on the type (monovalent or divalent cation) and salt concentration. Moreover, at fixed salt amounts, higher values of maximum force were reached using a concentration of 1% (w/w) gellan. Young modulus, determined using Hertz approach, showed values between 445 and 840 kPa depending on polysaccharide concentration and salt type added. Mechanical properties are critical features of gel beads and can define their suitability for a specific application. Therefore, the results obtained, mainly intrinsic properties such as Young modulus, could be a tool for comparing and choosing polysaccharides for specific uses.

QbD enabled Process Variable Study to Develop Sustained Release Chitosan-Alginate Embedded Delivery System for Improved Patient Compliance

The current investigation entail systematic Quality by Design (QbD)-enabled approach for the development of Sustained released embedded drug delivery systems of L-Arginine employing ionic gelation technique to attain improved patient compliance. Hence, in this QbD enabled systematic approach; quality target product profile (QTTP) was defined and critical quality attributes (CQAs) were identified. Further the risk assessment studies were undertaken through Ishikawa fish bone diagram to locate the critical material attributes (CMAs) and/or critical process parameters (CPPs) for the formulation of beads that may affect CQAs of drug product. A face centered central composite design (CCD) for two factors at three levels each with α =1 was employed for the optimization process to checkout the impact of concentration of sodium alginate and concentration of chitosan as CMAs which wereprior identified from risk assessment study and further evaluated for CQAs viz. bead size, swelling index and percent drug entrapment. The optimum formulation was embarked upon by using mathematical model being developed yielding desired CQAs. Thereby chitosan coated calcium-alginate delivery system was successfully developed by strategically employing QbD approach.In a nutshell, the presentinvestigation reports the successful development of optimized chitosan coated alginate beads employing QbD approach which can serve as a platform for other drugs too.

Development and Characterization of Natural Product Derived Macromolecules Based Interpenetrating Polymer Network for Therapeutic Drug Targeting.

Interpenetrating polymer network (IPN)-based bead formulations were exploited by cross-linking different hydrophilic polymers in different combinations and at different ratios. Polyvinyl alcohol, xanthan gum, guar gum, gellan gum, and sodium alginate (Na-alginate) were used in this work as hydrophilic polymers to enhance the solubility of diclofenac sodium and also to target the delivery at preferred locations. IPN beads based on polysaccharides were prepared by the ionic gelation method. Differential scanning calorimetry, powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy data showed that the IPN microbeads solubilized and encapsulated the drug within the network. We found over 83% encapsulation efficiency of the drug delivery system for the drug, and this efficiency increased with the concentration of the polymer. Ex vivo experiments using the goat intestine revealed that the IPN microbeads were able to adhere to the intestinal epithelium, a mucoadhesive behavior that could be beneficial to the drug pharmacokinetics, while in vitro experiments in phosphate buffer showed that the IPN enabled significant drug release. We believe that these IPN microbeads are an excellent drug delivery system to solubilize drug molecules and ensure adhesion to the intestinal wall, thereby localizing the drug release to enhance bioavailability of poorly soluble drugs.

Optimisation of alginate-pectin bead formulation using central composite design guided electrospray technique

Alginate-pectin beads act as a carrier in improving the oral bioavailability of bioactive compounds. Electrospray technique facilitates the production of uniform size and shape of alginate-pectin beads. Interaction between key electrospray process parameters affects the size and shape of the beads. A proper model should be employed to establish these correlating interactions. In the present work, the electrospray technique was guided with a central composite design (CCD) and response surface methodology (RSM). One quadratic and one linear model were obtained for size and sphericity coefficient, respectively. The CCD-RSM empirical model derived from the present work is essential to determine the significant factors and their levels in producing beads with consistent size and sphericity coefficient. The results indicated that the applied voltage had the most significant influence on size, while the alginate-pectin concentration was the most prominent factor in producing spherical beads. Spherical beads with a minimum size of 2.97 mm were obtained at an alginate-pectin concentration of 3.5%, a flow rate of 10.0 mL/h, an applied voltage of 2.4 kV, and a distance between the nozzle and the gelation bath of 16.0 cm.

Covalent immobilization of Dothideomycetes sp. NRC-SSW chitosanase and its application in chitosan hydrolysis

Chitosanases are chitosan specific glycosyl hydrolases that can exploit in several biotechnological applications. In the current study, a modified bead of carrageenan and carboxymethyl cellulose was used for the covalent immobilization of Dothideomycetes sp. NRC-SSW chitosanase. The immobilization process was optimized and the immobilization recovery was increased up to 69%. The stepwise different bead formulations were examined under Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Thermal Gravimetric analysis, confirming the success of the immobilization process. Additionally different properties including enzyme storage, thermal and pH stabilities were examined and an improvement in all of these properties was estimated. Although the same Vmax value (23.8U/min/mg protein) was recorded for the free and the immobilized enzymes, the Km was 10mg chitosan/ml and 16.67mg chitosan/ml for the immobilized and free form respectively. The activation energy for chitosan hydrolysis using the immobilized enzyme (12.497kJmol−1) was less than the third of that recorded for the free one (42.196kJmol−1). Furthermore, the immobilized enzyme was stable until the 5th cycle at which it retained more than 50% of its original activity. All the tested parameters confirmed that the immobilized Dothideomycetes sp. NRC-SSW chitosanase was more applicable for chitosan hydrolysis than the native enzyme.