Alginate-chitosan Beads Research Articles

Immobilization of lipase enzyme extracted from thermophilic Bacillus licheniformis 14T local isolate

Background: Currently, lipase enzymes are considered important bio-catalysts in many industries due to their unique properties in catalyzing various types of reactions in aqueous solutions. By targeting hydrocarbons in the oil, lipase enzymes contribute to the breakdown of hydrocarbons, reducing the environmental impact of oil spills and facilitating the remediation of contaminated areas.Methods: A thermostable lipase from local isolate Bacillus licheniformis 14T has been immobilized on four different supports that include the inactivated chitosan beads, activated chitosan beads with glutaraldehyde, inactivated chitosan-alginate beads, and activated chitosan-alginate beads with glutaraldehyde.Results The purified free lipase enzyme exhibited the highest enzymatic activity at 34.6 units/ml, surpassing all immobilized enzymes. Specific activity increased to 96.25 and 79.03 unit/mg protein for activated chitosan beads and activated chitosan-alginate beads, while decreasing to 52.95 and 46.05 unit/mg protein for inactivated chitosan beads and inactivated chitosan-alginate beads compared to the free enzyme. Optimal conditions for the immobilized enzyme differed, with the highest enzyme activity achieved after 60 minutes at 60°C and pH 8, reaching 48.6, 70.23, 43.12, and 61.2 units/ml on various supports, contrasting with the free enzyme's peak activity after 30 minutes at 50°C and pH 7.Conclusions: Immobilizing the lipase enzyme increases the specific activity of the immobilized enzyme on the supports of activated chitosan beads with, also the immobilization process led to a change in the optimal conditions for the activity of the immobilized enzyme compared with the optimal conditions of free enzyme.Keywords: Lipase; Bacillus licheniformis; Immobilization; Chitosan; Alginate

Application of Rice Husk Immobilized in Chitosan-Alginate Beads as A Biosorbent for Acid and Basic Dye Removal

Application of Rice Husk Immobilized in Chitosan-Alginate Beads as A Biosorbent for Acid and Basic Dye Removal

Adsorption of As(V) and P(V) by magnetic iron-based alginate-chitosan beads: Competitive adsorption and reduction mechanism of As(V) induced by Fe(II)

Assessing the adsorption competition between arsenate (As(V)) and phosphate (P(V)) is crucial due to their coexistence in water. This paper studied the competitive adsorption processes of As(V) and P(V) on magnetic iron-based alginate-chitosan beads by beaker experiments, simultaneously using XRD and FTIR techniques for characterization. In the single system, both As(V) and P(V) adsorption on M-IACBs followed the Langmuir model, with maximum adsorption capacities of 14.2 ± 0.4 mg g−1 and 18.5 ± 0.4 mg g−1, respectively. In the binary system, the competitive adsorption of As(V) and P(V) is a multilevel heterogeneous process well evaluated by the extended Freundlich and pseudo-second-order models. When loaded simultaneously, the adsorption of As(V) was more significant than that of P(V) (2.72 mg g−1 vs. 1.71 mg g−1). The desorption of P(V) was favored over As(V) during sequential loading, and the adsorption of P(V) was more influenced by pH compared to As(V). The adsorption affinity of the composites follows the order: As(V) < P(V) (for the single system) and As(V) > P(V) (for the binary system). Finally, changes in arsenic species were studied under anoxic aqueous solutions and oxygen-enriched air. In aqueous solutions, As(V) is reduced to the more toxic and mobile As(III) by Fe(II), and As(III) exhibits desorption-readsorption behavior. In oxygen-enriched air, As(V) undergoes electron transfer with Fe(II) and O2, resulting in the appearance of As(III), which can also be oxidized back to As(V). This study provides an objective and critical evaluation of the data regarding the use of Fe-based adsorbents in removing As(V), offering novel insights for designing such adsorbents.

β-Sitosterol Oleate Synthesis by Candida rugosa Lipase in a Solvent-Free Mini Reactor System: Free and Immobilized on Chitosan-Alginate Beads

Candida rugosa lipase (CRL) was immobilized by the ionic gelling technique using alginate and chitosan as encapsulating agents. An immobilization yield of 99% and an immobilization efficiency of 51% were obtained. Maximum hydrolytic activity for free and immobilized CRL was detected at 40 °C and for synthesis activity at 35 °C. The optimum pH for immobilized and free CRL hydrolysis activity was 8.0. The Vmax obtained for the hydrolysis reaction was higher for free CRL (4121.4 μmol/min/g) compared to immobilized CRL (2359.13 μmol/min/g). A Vmax of 2.24 μmol/min/g was detected for the synthetic activity of free CRL. The Km obtained for the hydrolysis reaction was higher (660.02 μmol/L) for immobilized CRL than for free CRL (403.06 μmol/L). For the synthetic activity, a Km of 234.44 μmol/L was calculated. The conversion of β-sitosterol oleate ranged from 80.85 to 96.84% for free CRL, higher than the maximum found for immobilized CRL (32%). The scale-up (scale factor: 50) with the free CRL was successfully performed, achieving a high conversion value (92%) in a 500 mL bioreactor. This conversion value was within the range predicted by the mathematical model obtained using mini reactors. These mini reactors are good models to test several conditions of enzyme reactions that are intended for large scales.

Controlled Drug Release Using Chitosan-Alginate-Gentamicin Multi-Component Beads.

This study aimed to develop improved multi-component beads with controlled, sustained delivery of antibiotics, such as gentamicin (GM). Antibiotic-loaded beads with rapid-release and the sustained-release system can be used for bone restoration. Single and multi-component beads were prepared by gelation using various combinations of chitosan and calcium chloride as cationic components and alginate and citric acid as anions. GM release was also controlled by crosslinking using citric acid. The optimum beads were obtained using 5% or 2% sodium alginate, 3% chitosan, and 0.1 mol/L citric acid. The beads were characterized by FTIR, TG-DTG, swelling behavior, and SEM. All GM-loaded beads revealed good antimicrobial activity. The rate and kinetics of release in the phosphate buffer solution were controlled by changing the amount of chitosan in the calcium chloride solution and using citric acid as the crosslinking agent. Crosslinked beads were prepared for the release of about 80% of the loaded drug within 24 h. The study concluded that the chitosan-alginate beads provided faster GM release but crosslinking with citric acid was efficient for sustained-release beads containing gentamicin.

Proteolytic activity and characteristics of skipjack tuna trypsin loaded alginate–chitosan beads as affected by drying methods and trehalose/glycerol

SummaryTrypsin‐loaded beads were produced using alginate and chitosan ionotropic gelation. Effects of drying methods (air‐drying and freeze‐drying) on characteristics and relative trypsin activity (RTA) of beads were studied. More homogeneous, spherical and smoother surface with larger size of beads and higher RTA were obtained by freeze‐drying method than those of air‐drying. Trehalose and/or glycerol at different concentrations (2.5 and 5%, w/v) were added in encapsulating materials and RTA of beads after freeze‐drying and after simulated gastric digestion (SGD) was monitored. Freeze‐dried trypsin beads with 5% glycerol (FDTB‐G5) showed highest RTA after SGD. Moreover, highest degradation was attained when fish mince and sodium caseinate were hydrolysed with FDTB‐G5 at a level of 100% of proteins tested in in vitro simulated gastrointestinal tract. Therefore, FDTB‐G5 had better physical characteristics, which could withstand acidic condition and retain trypsin activity, thus favouring proteolysis when delivered to intestinal tract.

Immobilization of maltogenic amylase in alginate-chitosan beads for improved enzyme retention and stability

Maltogenic amylase (Mag1) is a potent enzyme that hydrolyzes the glycosidic bond of polysaccharides to produce malto-oligosaccharides (MOS). However, the Mag1 enzyme has poor stability and reusability, leading to inefficient MOS production. Enzyme immobilization is a promising method to solve the enzyme stability problem. Entrapment and encapsulation technique was used in this study to immobilize Mag1 because of high biocompatibility and prevention of enzyme degradation, hence lesser loss of enzymatic activity. Chitosan was used as a coating membrane on the alginate matrix, preventing enzyme leaching from the beads. Mag1 entrapped in alginate-chitosan beads showed better performance compared to alginate beads in terms of thermostability, reusability and enzyme retention. Alginate-chitosan beads showed improvement of temperature stability of approximately 35%, 30% and 20% at a respective temperature of 30 °C, 40 °C and 50 °C. Reusability analysis showed immobilized Mag1 can be used up to at least eight cycles with retained activity of 80% and 70% from its initial activity for alginate-chitosan and alginate beads respectively. Enzyme leakage percentage in alginate-chitosan was 7-21%, while that in alginate was 12-35%. The overall findings envisage the promising application of alginate-chitosan beads immobilized Mag1 as a biocatalyst for MOS synthesis.

Potential of Longan Seed Extract–Loaded Alginate–Chitosan Beads as Drug Delivery System

The potential of a drug delivery system of the longan seed extract (LSE) incorporated in the alginate/chitosan (Alg/CS) beads has been studied. The LSE-loaded Alg/CS beads were prepared using the ionic gelation method via the interaction between protonated amino groups of CS and negatively charged carboxylic groups of Alg. Properties of the LSE-loaded Alg/CS beads were investigated including the morphology of the beads, particle sizes, encapsulation efficiency (%EE), controlled release profile, cytotoxicity, and biocompatibility. From the results, the amount of gallic acid, ellagic acid, and corilagin found in LSE was 25.61 ± 0.48,18.83 ± 3.75, and 21.92 ± 1.42 mg/g (based on the weight of LSE), respectively. The half-maximum inhibitory concentration (IC50) of LSE was 24.29 ± 1.08 μg/ml. SEM images of the LSE-loaded Alg/CS beads showed spherical shapes and rough surfaces with some aggregation. The particle sizes were between 1.9 and 2.5 µm with the PDI values of 0.1503–0.3183. Encapsulation efficiencies were between 11 and 18%. The released amount of LSE from the LSE-loaded Alg/CS beads was ranging between 68 and 93%. Moreover, cytotoxicity and biocompatibility tests showed that the beads were non-toxic to both NCTC clone 929 and NHDF cells and promoted the attachment of NHDF cells. Thus, these beads could be used as polymeric drug carriers.

Optimization of Ultrasound-Assisted Extraction and Encapsulation of Antioxidants from Orange Peels in Alginate-Chitosan Microparticles.

The recovery of bioactive compounds from waste and modification of their properties by encapsulation are the main challenges today. In this study, the ultrasound-assisted extraction of antioxidants from orange peels was optimized using a central composite design. Ethanol (50%, v/v) was the solvent of choice for their extraction. The obtained total antioxidant contents were fitted using the second-order polynomial equation. The optimal conditions were the extraction time of 30 min, temperature of 60 °C, and the liquid-to-solid ratio of 15 mL/g. After that, the optimal extract was encapsulated in alginate-chitosan beads to modify the release of antioxidants under gastrointestinal tract conditions. The average size of beads was 252 µm, while the encapsulation efficiency was 89.2%. The results of the FTIR analysis indicated that there are no interactions between compounds of the extract and alginate-chitosan. In vitro release studies showed an initial rapid and then slow release of antioxidants. This release followed the simple Fickian diffusion. The encapsulation of orange peel extract provided improvement in the delivery of antioxidants after gastrointestinal digestion. The obtained encapsulated beads can be applied as the natural active ingredient of food, cosmetics, and pharmaceutical products.

One-step solid-state fermentation for efficient erythritol production from the simultaneous saccharified crop wastes by incorporating immobilized cellulase

Crop wastes are advantaged feedstocks for low-cost erythritol production via Yarrowia procedure, whereas a high amount of cellulose remains in the fermentative medium due to the lack of cellulase. The present study proposed a one-step solid-state fermentation (SSF) for erythritol production from oil crop waste that was simultaneous saccharified by the incorporated exogenous cellulase. Cellulase was immobilized in alginate-chitosan beads, and the outstanding performance of the immobilized cellulase in erythritol cultivation was proven based on its tolerance to pH and osmotic pressure, with high stability and reusability (83% of activity maintained after five cycles of utilization). Under the optimal condition of pH 6.0 and 0.01 g/g dry substrate with the immobilized cellulase addition of 1.5% (w/w), persistent cellulase activity accompanied by the efficient consumption of total sugar was detected during the cultivation. Enhanced erythritol production was achieved with the highest titer of 226.8 mg/g dry substrate in scale-up batch fermentation, when the fed-batch cultivation contributed to a considerable total amount of erythritol. Cost analysis suggests that the present process leads toward the development of eco-friendly and economically feasible erythritol production.

Encapsulation of Lemongrass Extract (Cymbopogon citratus) Coated Alginate/Chitosan Using Gelation Method

Lemongrass (Cymbopogon citratus) is a medicinal plant with various biological activities such as antibacterial, antifungal, antiprotozoal, anti-inflammatory, and antioxidant. This study aimed to encapsulate lemongrass bioactive in alginate/chitosan complex by enhancing the properties of CaCl2 crosslinked incorporated with tween 80 by ionic gelation method. The hydrogel was prepared by mixing alginate solution (2% w/v) and chitosan solution (1% w/v) with a ratio (1:1 v/v). Tween 80 (2% v/v) was added as a dissolution enhancer and CaCl2 as a crosslinker agent. The formulation varying by concentration of CaCl2 (0.1M to 0.3M) and lemongrass extract (2% to 12%). Encapsulation lemongrass with alginate-chitosan beads is characterized to determine encapsulation efficiency, swelling study, morphology, functional groups, and release study. The results showed that encapsulation efficiency ranged from 74.81% to 83.07%. Encapsulation efficiency increased with the addition of CaCl2 and lemongrass extract concentration. The swelling ratio ranged from 27.29 to 37.81, it will decrease with the addition of CaCl2 and lemongrass extract concentration. The Scanning Electron Microscopy (SEM) analysis of hydrogel beads shows a polyhedral shape, porous, and rough surface which indicates bioactive of lemongrass trapped on the beads. The Fourier Transform Infrared Spectroscopy (FTIR) results show new peaks at 1734 cm-1 as carbonyl stretch vibrations in ketones, aldehydes, and carboxylic acids, indicating the addition of lemongrass extract. Bioactive of lemongrass extract loaded alginate-chitosan beads was successfully released as much as 87.12% at pH 6.8. This study suggested the strong potential alginate-chitosan beads as an encapsulating agent for lemongrass extract using the ionic gelation method, and it has potential as a drug delivery system.Keywords: encapsulation; lemongrass; alginate; chitosan; CaCl2

In vitro Digestion and Swelling Kinetics of Thymoquinone-Loaded Pickering Emulsions Incorporated in Alginate-Chitosan Hydrogel Beads.

The present work aimed to investigate the swelling behavior, in vitro digestion, and release of a hydrophobic bioactive compound, thymoquinone (TQ), loaded in Pickering emulsion incorporated in alginate-chitosan hydrogel beads using a simulated gastrointestinal model. In this study, oil-in-water Pickering emulsions of uniform micron droplet sizes were formulated using 20% red palm olein and 0.5% (w/v) cellulose nanocrystals-soy protein isolate (CNC/SPI) complex followed by encapsulation within beads. FT-IR was used to characterize the bonding between the alginate, chitosan, and Pickering emulsion. 2% (w/v) alginate-1% (w/v) chitosan hydrogel beads were found to be spherical with higher stability against structural deformation. The alginate-chitosan beads displayed excellent stability in simulated gastric fluid (SGF) with a low water uptake of ~19%. The hydrogel beads demonstrated a high swelling degree (85%) with a superior water uptake capacity of ~593% during intestinal digestion in simulated intestinal fluid (SIF). After exposure to SIF, the microstructure transformation was observed, causing erosion and degradation of alginate/chitosan wall materials. The release profile of TQ up to 83% was achieved in intestinal digestion, and the release behavior was dominated by diffusion via the bead swelling process. These results provided useful insight into the design of food-grade colloidal delivery systems using protein-polysaccharide complex-stabilized Pickering emulsions incorporated in alginate-chitosan hydrogel beads.

Cottage cheese enriched with lactobacilli encapsulated in alginate–chitosan microparticles forestalls perishability and augments probiotic activity

The study aimed to investigate the effects of Aloe vera gel (AvG) and multi-layered microencapsulation on the survival of five Lactobacillus species in cottage cheese during 28 days of refrigerated storage. Testing of the probiotic and AvG-loaded synbiotic microparticles under simulated human digestion conditions showed that the synbiotic beads for L. fermentum, L. rhamnosus, and L. plantarum were on the average 8%–10% better than their probiotic counterparts. AvG augmented the antioxidant activity of synbiotic beads of L. rhamnosus and L. plantarum by 20%–30% and inhibition of foodborne pathogens by twofold in comparison with the control and probiotic particles. Synbiotic cheese also exhibited a more or less same sensory profile as the control cheese. These results suggest that cottage cheese fortified with AvG filled alginate–chitosan beads loaded with either L. rhamnosus or L. plantarum strains, can prevent pathogen invasion, maintain functional qualities, and deliver more probiotics to the human gut. Practical applications The success of microencapsulating probiotics has been marred by its inability to ensure adequate cell viability. Co-encapsulation with prebiotics has circumvented this bottleneck, the degree of success greatly dependent on the choice of prebiotic material used. Fresh cottage cheese embedded with a tripartite blend of bioactive elements has better shelf life and safety constitutes a potentially novel fourth-generation synbiotic that is commercially exploitable.

Synthesis of Chitosan-Alginate Beads and Its Application for Alkyl Benzene Sulfonates (ABS) Adsorption

ABS is the largest group of anionic surfactants. Anionic surfactants (AS), especially ABS are used extensively due to their impacts on ecosystems and are usually disposed of after their usein the environment. Therefore, they represent one of the main causes of water pollution. Methods have been proposed to remove surfactants such as adsorption with beads. This study aims to analyze the results of the synthesis and characterization of chitosan-alginate beads and determine the efficiency adsorption of ABS. The synthesized beads were characterized by swelling tests. To find out the maximum efficiency of ABS, ABS adsorption with chitosan-alginate beads was carried out by varying pH (5, 6, 7, 8, and 9), time (15, 30, 45, 60, 75, and 90 minutes) and ABS concentration (10, 20, 30, 40, and 50 mg/L). The results of the adsorption solution were measured by a UV-Vis spectrophotometer.Theresults of theswelling test onbeadsfor 24 hoursreachedanaverage of 148.18%.The maximum efficiency adsorption of chitosan alginate beads was determined to be 46.46% with an initial ABS concentration of 30 mg/L at pH 6 in 60 minutes.

In Vitro Evaluation of Insulin Release from Chitosan-Alginate Macrobeads

Oral delivery of peptide/protein is quite difficult due to physiological barriers. Encapsulation of these drugs in the suitable biopolymeric matrix could protect the drug as well as increase the residence time of the formulation. Mucoadhesive biopolymers are being widely investigated for this purpose. We have fabricated insulin-loaded chemically crosslinked chitosan-alginate macrobeads of approximate size 3 mm per bead. The beads were characterized for surface morphology and polymeric interaction using SEM, EDX, and FTIR, respectively. The swelling profile and insulin release were analyzed in water and PBS for 9 h. The surface had uniform undulations as observed by SEM. EDX confirmed the chemical crosslinking of chitosan and alginate. FTIR further confirmed the interaction among the polymers. The swelling study revealed a gradual increase for some time and then a decrease in weight possibly due to the disintegration of beads. A cumulative release of approximately 35% was observed by the end of 9 h in both the dissolution medium. This work is done to investigate the possibility of release of protein/peptide drugs from polysaccharide biopolymer-based blended hydrogel matrix for possible non-invasive delivery of such drugs orally. Here, we have formulated mixed polyelectrolyte hydrogel beads of chitosan and alginate encapsulating insulin as the model drug. Our work shows a sustained release of insulin from the chitosan-alginate beads.

Enhanced biocatalysis of phenanthrene in aqueous phase by novel CA-Ca-SBE-laccase biocatalyst: Performance and mechanism

Enzymes-mediated biocatalysis is believed to be a promising strategy for the degradation of polycyclic aromatic hydrocarbon (e.g., phenanthrene) in aqueous phase, due to its high efficiency and environmental harmfulness. However, the reusability of enzymes-mediated biocatalysis and its requirement for redox mediators limited its application. In this paper, enhanced phenanthrene removal was achieved by using a novel biocatalyst which coencapsulating laccase and natural redox mediator soybean meal extract on calcium modified chitosan-alginate (CA-Ca-SBE-laccase) beads with a network pore structure. High degradation efficiency of 94.4 % was achieved after treating aqueous solutions of 0.5 ppm phenanthrene for 20 min with the CA-Ca-SBE-laccase beads, which was 20–30 % higher than that of free laccase and ordinary immobilized laccase beads. Both the radical pathway of oxygen-containing stable free radicals and the nonradical laccase-SBE combined substrates with higher redox potential generated in CA-Ca-SBE-laccase beads contributed to the degradation of phenanthrene, and achieved the maximum double synergy of mediator and laccase. Benefiting from redox-mediating encapsulated SBE and from Ca modification of chitosan, the biocatalyst maintained fairly stable catalytic activities over a wide range of pH values, and considerable repeatability and storage stability were obtained. This study put forward an efficient laccase, redox mediator and immobilized support cofunctionalization technology, and would provide a new perspective for the increasing application scope of enzymes-mediated biocatalysis.

Physical characterization of chitosan/gelatin-alginate composite beads for controlled release of urea

Polymer-based controlled-release formulations are gaining significant advantage over chemical fertilizers in recent years as they contribute to the preservation of soil fertility by reducing soil pollution in farm lands. In this work, urea (a nitrogen source fertilizer) has been entrapped within chitosan-alginate and gelatin-alginate composite beads at three different concentrations. The physical properties of the polymer composite beads namely the diameter, porosity, yield percentage, Carr's index and Hausner's ratio were determined. These fertilizer-loaded beads were also characterized by Scanning Electron Microscopy (SEM) and Fourier Transform-Infra Red (FT-IR) spectroscopy. Urea enhanced swelling of chitosan-alginate beads through the creation of pores whereas in the case of gelatin-alginate formulations, urea decreased the swelling. The swelling of the polymer composite beads was found to be maximum at pH of 5.6 when compared to that of pH conditions, 7 and 8.5. The chitosan-alginate composite beads were found to possess better fertilizer entrapping efficiency than the gelatin-alginate composite beads. The in vitro urea release studies demonstrated that the urea-entrapped gelatin-alginate beads exhibited slower urea release than that of the chitosan-alginate beads. These controlled release urea formulations were found to follow quasi-fickian diffusion mechanism.

Efficient production of bioactive structured lipids by fast acidolysis catalyzed by Yarrowia lipolytica lipase, free and immobilized in chitosan-alginate beads, in solvent-free medium

Structured lipids (SL) represent a new generation of lipids, considered bioactive compounds. Medium-chain, oleic (18:1n-9), and medium-chain fatty acid (MCFA) structured lipids (MOM-SL) were produced by acidolysis reaction in solvent-free medium with capric (10:0) and lauric (12:0) free fatty acids (FFAs) and triolein or olive oil, using Yarrowia lipolytica lipase as biocatalyst. MCFAs were rapidly incorporated into sn-1,3 SL in acidolysis reactions with triolein and olive oil, up until 30% of incorporation efficiency of capric and lauric acids in SLs. The kinetics of MCFA incorporation in MOM-SL was influenced by the FFA:TAG molar ratio, and for reactions between triolein and lauric acid, increasing FFA:TAG from 2:1 to 4:1 enhanced MCFA incorporation in SL. Y. lipolytica lipase showed a strictly 1,3-regioselective profile in acidolysis reaction, confirmed by nuclear magnetic resonance spectroscopy. Immobilization of this lipase by microencapsulation in chitosan-alginate beads resulted in similar incorporation efficiency for lauric acid with olive oil TAG and this reaction could be performed for 5 cycles without catalytic activity loss. This lipase showed promising properties as a potential biocatalyst that may be effectively used in production of bioactive structured lipids, which might be applied for prevention of metabolic and inflammatory disorders related to obesity.

Chitosan-alginate beads as encapsulating agents for Yarrowia lipolytica lipase: Morphological, physico-chemical and kinetic characteristics

Extracellular lipase from Yarrowia lipolytica was immobilized by ionotropic gelation with alginate and chitosan as encapsulating agents. Photomicrographs revealed a collapsed and heterogeneous surface of these microcapsules due to freeze-drying process. The optimum reaction temperature for the microencapsulated lipase (40 °C) was higher than for free lipase (35 °C) as well as the optimum pH (8.0 and 7.5, respectively). The study of the reaction kinetics showed that a higher maximum reaction rate (Vmax) (221.1 U/mg) for the free lipase in comparison to the immobilized form (175.3 U/mg). A protective effect of the microcapsule was detected in the storage of the enzyme at room temperature, as after 75 days 35% of activity was maintained for the microcapsules, while no activity remained after 15 days with the free enzyme. Lower values for inactivation constant (kd) and increase in half-life for immobilized lipase showed that lipase microencapsulation favored the thermostability of this enzyme.

Enhancing the efficiency of ethanol production from molasses using immobilized commercial Saccharomyces cerevisiae in two layer alginate-chitosan beads

The commercial Saccharomyces cerevisiae has been successfully inoculated and immobilized in the present study. The immobilization was conducted through a double layer encapsulated method in which 3% of alginate and 1% of chitosan become the first and second layer, respectively. The light microscopy confirmed that the inoculated-cell was dispersed and spread well in the alginate layer as the first layer. The interaction between alginate-chitosan was confirmed by Fourier Transform Infra-Red (FTIR), and the results demonstrated the physical interaction without forming any chemical interaction and binding in the immobilized cell. The immobilized cell was then used for producing ethanol from molasses through the batch fermentation process. The immobilized cell can successfully convert the glucose to ethanol and used for three cycles of fermentation before finally being saturated. The saturated was generated by breaking down of the chitosan layer generated by cell proliferation. The layer breakage forms the fouling as the effect of absorbed molasses in the surface of layer. However, the fermentation using immobilization cells provides the high-efficiency process by converting high percentages of ethanol yield production and solve the post-treatment process.