Adding Sodium Alginate Research Articles

Dual-network design to enhance the properties of agar aerogel adsorbent by incorporating in situ ion cross-linked alginate

Natural and synthetic adsorbents are used to remove contaminants from polluted waters. In particular, polymer-based aerogels are promising but their adsorption capacity and dimensional stability should be improved. Here we propose a new design strategy to prepare a dual-network aerogel, consisting of physical cross-linked agar and Ca2+ cross-linked sodium alginate as the first and second networks, respectively. After introducing cross-linked sodium alginate into the agar matrix, the morphology of the agar aerogel transformed from a distinct layered structure to a co-continuous network. The swelling degree ratio of the agar aerogel is reduced, and the dimensional stability was improved by introducing ion cross-linked sodium alginate into the agar matrix. The aerogels were used as adsorbents to remove methylene blue from aqueous solutions. The adsorption capacity of the agar aerogel was remarkably improved by adding sodium alginate due to the increase in electrostatic attraction and adsorption site.

Preparation of nano-sized HZSM-5 zeolite with sodium alginate for glycerol aromatization

A facile method was developed for the synthesis of highly crystallized nano-sized HZSM-5 via adding sodium alginate into zeolite precursor solution. The effects of addition order and dosage of sodium alginate on the physicochemical properties of the catalysts were systematically studied by XRD, FT-IR, TEM, N2 adsorption–desorption, ICP-OES, 27Al MAS-NMR and NH3-TPD. It was found that the addition order and dosage of sodium alginate have strong influences on the crystal sizes and acidic properties of the obtained catalysts. About 100 nm crystals were generated in S-HZSM-5-0.75-p through adding the sodium alginate prior to TEOS, which were smaller than the crystal size of conventional HZSM-5 (200–350 nm). However, this method was unfavorable for the incorporation of Al into the framework of HZSM-5. The low content of framework Al could cause a decrease in acidity and the amount of acid sites was only 0.38 mmol g−1 in S-HZSM-5-0.75-p, which was slightly lower than conventional HZSM-5 (0.42 mmol g−1). In contrast, smaller crystals (50 nm) and more acid amounts (1.24 mmol g−1) could be obtained for the S-HZSM-5-0.75 synthesized by adding the sodium alginate after TEOS. Nevertheless, the crystals could be easily aggregated to a dandelion-like particles and possessed fewer acid sites when the sodium alginate was added excessively. Under the conditions of 0.1 MPa, 400 °C and a WHSV of 0.96 h−1, a desired 35.06% BTX yield with 8.5 h service lifetime in glycerol aromatization was obtained over S-HZSM-5-0.75 comparing with conventional HZSM-5 (22.19% BTX yield and 3.5 h service lifetime). The remarkable improvement in catalytic performance of nano-sized HZSM-5 zeolite was mainly attributed to the more acid amounts and smaller crystal size, which could increase the accessibility to the acid sites and shorten the diffusion path length.

Alginate Encapsulation of Trichoderma harzianum as Biocontrol Agent against Brown spot Disease on Rice (Oryza sativa) in Vitro Assays

Brown spot caused by Bipolaris oryzae is an important rice disease which can cause a reduction in yield and grain quality in Malaysia. The application of chemical agents in controlling the brown spot disease can cause undesirable effects such as residual toxicity, environmental pollution, and development of pathogen resistance to fungicides. Instead, biocontrol methods have to be developed to ensure environmental safety, the longevity of usage while effective methods of plant disease management. However, to the best of our knowledge, no research has been conducted about alginate encapsulation of Trichoderma harzianum. Therefore, the objectives for this study is to measure the performance of encapsulation of Trichoderma harzianum isolates in controlling the brown spot disease on rice. Alginate encapsulation was produced from conidial suspension by adding sodium alginate and calcium chloride which result in small beads. The isolate was isolated and characterized based on morphological characters and have been proved by pathogenicity tests. Based on the results dual culture test showed the highest percentage inhibition of radial growth which was 85.07% with 10 replication of Bipolaris oryzae. The findings from this study can be used as an alternative method to control brown spot disease which will render easier application to rice plantation in the future which suit for commercial purposes and contamination-free environment.

Evaluation of hMSCs Response to Sodium Alginate / Bioactive Glass Composite Paste: Effect of CaO/P2O5, Sodium Alginate Concentration and P/L Ratios.

Bioactive glasses with different compositions have been extensively used as bone tissue engineering. Preparation, development and characterization of alginate pastes containing bioglass for bone repair applications were the purposes of this study. The injectable bone pastes were produced from sol-gel derived bioactive glass nanoparticles with various CaO/P2O5 ratios of 19, 9.5 and 4.75 and sodium alginate solutions with different concentrations of 1, 2 and 4 wt.%. The effect of CaO/P2O5 and powder to liquid (P/L) ratios and alginate concentration on injectability, biodegradation, rheological properties, bioactivity and cellular behavior of the pastes have been studied. The behavior of human mesenchymal stem cells (hMSCs) in the presence of the pastes was assessed by MTT assay, biomineralization assay, ALP activity, Acridine orange staining and Alizarin red staining tests. By adding sodium alginate, the pastes exhibited a thixotropy behavior. The storage modulus of all pastes was larger than the loss modulus in the frequency range of 0.1-100 s-1. Cytotoxicity evaluation results revealed that there was a critical amount of bioactive glass in pastes which are above the limit; the viability of hMSCs will be at risk. The pastes made of bioactive glass nanoparticles with CaO/P2O5 = 9.5 and sodium alginate 1% with P/L ratio of 0.8 showed optimum behavior in terms of mineral carrying capacity, injectability characteristics, accellular bioactivity in SBF, loss weight and wash out behavior, proliferation and differentiation of hMSCs. According to the results, the pastes prepared with sodium alginate solution and bioactive glass nanoparticles can be beneficial in bone tissue engineering.

Degradable thermosensitive injectable hydrogels with two-phase composite structure from aqueous solutions of poly(N-isopropylacrylamide-co-5,6-benzo-2-methylene-1,3-dioxepane)—poly(ethylene glycol) triblock copolymers and biopolymers

Novel degradable thermosensitive injectable hydrogels with two-phase composite structure and improved mechanical strength were prepared by adding sodium alginate or dextran to the aqueous solution of a hydrolytically degradable ABA triblock copolymer with poly(ethylene glycol) middle block and poly(N-isopropylacrylamide) containing in-chain ester groups as side blocks. The two-phase structure, demonstrated by SEM measurements, resulted as a consequence of the triblock copolymer-biopolymer incompatibility. The biopolymer addition decreased the gelation temperature (T gel) and strongly improved the viscoelastic properties of the resulted hydrogel, whose behavior at 37 °C turned from liquid-like to a gel-like one. The composite hydrogels displayed low gelation time and high stability (i.e., no sign of syneresis after 42 days) at 37 °C. They partially degraded in PBS at 37 °C as a consequence of the hydrolysis of the in-chain ester groups of the thermosensitive blocks, leading to a progressive increase of T gel and decrease of gel strength. The ability of the composite hydrogels to control the release rate of drugs was tested in PBS at 37 °C by employing 5-flurouracil (5FU) and chlorambucil (CLB) as model drugs with different hydrophilicity. 5FU displayed a pretty fast release rate, unlike CLB whose release rate was much slower, no effect of the biopolymer nature being noticed. During the drug release experiments, the hydrogels showed a moderate mechanical stability, although higher than in the absence of the biopolymer, and also progressively dissolved within 12–17 days because of the hydrogel erosion phenomenon, probably accelerated by the partial degradation of the triblock copolymer.

A fabrication of colorimetric sensor using pH indicator for determination of toxic gases

Event Abstract Back to Event A fabrication of colorimetric sensor using pH indicator for determination of toxic gases Sung Yeol Kim1, Joon Woo Chon1, Jong Hyun Ko1 and Dong June Chung1 1 Sungkyunkwan University, Department of polymer science & engineering, Korea Critical toxic gases have been used in the several industrial plants. So workers were exposed to many kinds of toxic gases without proper safety guard in the field. Low concentration of toxic gases injures the eyes, nose, and respiratory organs and cause allergic reaction [1]. These gas leaks emerged as a social issue, because Exposure of toxic gases was fatal for the long term. The World Health Organization(WHO) has set a safe exposure stand respectively [2]. Colorimetric detection of gases has been used for years. They are based on the change in color of pH indicators incorporated in a porous matrix [3]. There were many researches of sensor detecting toxic gases used by pH indicators [4], but there were many disadvantages during the measurement. Expensive analytical instruments are needed, and it takes a long time to obtain the results [5]. In this study we found that it is better and easier to use simple pH indicators to detect toxic gases. We made convenient pH indicator-based films for detecting 4 types of toxic gases easily. Using polymeric binder, the pH indicators were embeded in a polymeric film. To improve sensitivity and reactivity, we added other additive for enhancement. So we could be observed by naked eyes without aid of analytical devices, and decrease the response time. As a result, we made films which reacted with toxic gases and which were faster than commercialized ones. To make pH indicator-based film sensors, we adopted a method of dip coating. Main substrate was non-woven fabric wiper(WW-2109), polymeric binder was a sodium alginate and cross linking agent was calcium chloride. To improve reactivity, benzoquinone was a additive as electron transfer agent. At first, we made a solution which added sodium alginate(1wt%), benzoquinone, and pH indicator(0.1wt%). Prepared films were impregnated again in the above solution. Then they were impregnated in a calcium chloride solution(10wt%) again. After finish to make sensor, toxic gases(20, 10ppm) was exposed constantly by mass flow controller(MFC). To observe degree of the color change, Spectrophotometer was used and the graph of ΔE*a*b* was drew every 5 seconds. Sodium alginate can use to crosslink with calcium chloride by ionic linkage. There was a good resistance to washing pH indicator in wet environment. From adding benzoquinone, the film`s color changed to the other color in the 10, 20ppm concentration of gases, and it reacted completely with in a minute. When colorimetric sensors contacted toxic gases exposed by MFC, they changed color from blue to yellow or yellow to blue, because of movement of proton. Benzoquione help a movement of proton. The change started after 10 seconds, when films contacted with toxic gases. Humidity is a important requirement. If humidity was high, its reactivity was more faster. After exposure of toxic gases, we used a spectrophotometer to confirm the degree of color change. Spectrophotometer digitize a image from using L*a*b* color coordinate. When we compared with before and after, we could know degree of the color change. Without crosslinking reaction, dye will get out of the wiper, but using the a crosslinking of calcium alginate, we improve water repellency of films in wet environment. By coating pH indicators and benzoquinone on films, it is possible to make films with more faster reactivity with in a minute. In the field, we can determine a gas leak by naked eye within a minute, and prevent unexpected accidents with this films. This work was supported by Fundamental Technology R&D Program for Society of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant NO. 2013M3C8A3075845).

Permeable reactive barrier of coarse sand-supported zero valent iron for the removal of 2,4-dichlorophenol in groundwater.

In this study, coarse sand-supported zero valent iron (ZVI) composite was synthesized by adding sodium alginate to immobilize. Composite was detected by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). SEM results showed that composite had core-shell structure and a wide porous distribution pattern. The synthesized composite was used for degradation of 2,4-dichlorophenol (2,4-DCP) contamination in groundwater. Experimental results demonstrated that degradation mechanism of 2,4-DCP using coarse sand-supported ZVI included adsorption, desorption, and dechlorination. 2,4-DCP adsorption was described as pseudo-second-order kinetic model. It was concluded that dechlorination was the key reaction pathway, ZVI and hydrogen are prime reductants in dechlorination of 2,4-DCP using ZVI.

Raw-appearing Restructured fish models made with Sodium alginate or Microbial transglutaminase and effect of chilled storage

Restructuring by adding Sodium Alginate or Microbial Transglutaminase (MTGase) using cold gelation technology make it possible to obtain many different raw products from minced and/or chopped fish muscle that are suitable for being used as the basis of new restructured products with different physicochemical properties and even different compositions. Special consideration must be given to their shelf-life and the changes that may take place during chilling, both in visual appearance and physicochemical properties. After chilled storage, the restructured models made with different muscular particle size and composition at low temperature (5 °C), it was observed that microbial growth limited the shelf-life to 7-14 days. Mechanical properties increased (p < 0.05) during that time, and higher values were observed in samples elaborated by joining small muscle particle size than in those elaborated by homogenization. There was no clear increase in the cooking yield and purge loss, and no significant colour change (p > 0.05) was detected during storage.

Study on Modified PVA- H<sub>3</sub>BO<sub>3</sub> Immobilization Microorganism Method for Hydrogen Production from Wastewater

A new immobilization microorganism (IM) method was built by adding sodium alginate, SiO2 and CaCO3 in gel and cross-linking with saturated H3BO3 aqueous solution with 2% CaCl2 for traditional PVA-H3BO3 method. The modified method was used for preparation IM for hydrogen production from waste water contained organics by sewage treatment plants’ sludge pretreated. The change rate of the IM balls diameter and unit hydrogen production were taken as the primary performance criterion of the IM. The modified IM method for hydrogen production from waste water contained organics was confirmed: 9% PVA and 0.9% sodium alginate for the embedding medium, saturated H3BO3 aqueous solution and 2% CaCl2 for cross-linking agent, and adding NaCO3 adjusting PH, 3%SiO2 and 0.5%CaCO3 for the support packing of IM balls, and the balls diameter of about 3mm. The modified IM balls had unit hydrogen production of 63.3% and total sugar removal rate of 143.4mL/h•L for washing model wastewater from ice cream factory, which contained 2000 mg/L total sugar and 5500mg/L COD, and higher mechanical strength. It were identified that the method could reduce outside surface’s shrink, and improve the homogeneous of inside endoporus structure of modified IM balls, and a similar inside microporosity and outside microporosity by SEM detection.

Effect on Mechanical Strength of Tricalcium Phosphate Cement by Additions of Sodium Alginate

The Calcium Phosphate Cement (CPC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry due to its biocompatibility, bioactivity and osteoconductivity, and form a paste that can be easily shaped and placed into the surgical site. However, CPCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. In order to assess the strength and time to handle a CPC composed primarily of alpha phase, were added sodium alginate (1%, 2% and 3% wt) and an accelerator in an aqueous solution. The cement powder was mixed with liquid of setting, shaped into specimens and evaluated for apparent density and porosity by Archimedes method, X-ray diffraction and compressive strength. A significant increase in compressive strength by adding sodium alginate was verified.

Study on fish allergen microcapsules and controlled-release kinetics

The aim is to prepare a kind of sodium alginate microcapsules which could slowly release fish allergens.The spherical alginate microcapsules were prepared by the ionotropic gelation method and the microcapsules were formed by adding sodium alginate into aqueous solution containing calcium chloride.The prepared microcapsules were characterized by FTIR,DSC and SEM methods.The releasing mechanism of parvalbumin from the microcapsules was established based on equation fitting of release kinetics model.Parvalbumin could be embedded into alginate microcapsules.The entrapment efficiency was 69.24% while the loading ratio was 21.06%.The surface of microcapsules which had plenty of tiny holes was rough.The result of protein release in vitro showed that parvalbumin released rapidly in the first 5 hours,and then gradually achieved maximum.The release kinetics model suited Higuchi equation and Ritger-Peppas equation well.Fish allergen could be entrapped by sodium alginate,meanwhile allergen controlled-release was achieved.The mechanism fits with skeleton erosion in addition to protein diffusion mechanism.

Efficacy of adding sodium alginate to omeprazole in patients with nonerosive reflux disease: a randomized clinical trial

Nonerosive reflux disease (NERD) is the most common form of gastroesophageal reflux disease. Patients with NERD have a lower response rate to proton pump inhibitors (PPIs) than patients with erosive esophagitis when gauged from relief of heartburn. Sodium alginate decreases the acidity of refluxate and protects the esophageal mucosa. However, whether the addition of sodium alginate to PPI therapy can improve NERD symptoms remains unknown. Accordingly, the aim of this study was to evaluate the efficacy of adding sodium alginate to basal PPI therapy for NERD. Patients who had experienced heartburn on at least 2 days per week during the 1-month period before entering the study and had no endoscopic mucosal breaks (grade M or N according to Hoshihara's modification of the Los Angeles classification) were randomized to one of two treatments for 4 weeks: omeprazole (20 mg once daily) plus sodium alginate (30 mL four times a day) (group A) or omeprazole (20 mg once daily) alone (group B). Eighty-seven patients were enrolled, and 76 patients were randomly assigned to group A (n = 36) or group B (n = 40). Complete resolution of heartburn for at least 7 consecutive days by the end of treatment was significantly more common in group A (56.7%) than in group B (25.7%). One patient from group A had mild drug-related diarrhea that was not clinically serious. In conclusion, omeprazole combined with sodium alginate was better than omeprazole alone in Japanese patients with NERD.

The addition of a pH-sensitive gel improves microemulsion stability for the targeted removal of colonic ammonia

BackgroundWe prepared an oral W/O microemulsion for the removal of colonic ammonia (ME-RCA). The effect of this microemulsion was influenced by the digestion process in the gastrointestinal tract. In this paper, we aim to show that stability was improved by using a microemulsion-based gel for the removal of colonic ammonia (MBG-RCA).MethodsMBG-RCA was prepared by adding sodium alginate to the ME-RCA. MBG-RCA and ME-RCA were passed through a simulated gastrointestinal environment, and the amount of colonic ammonia present was then determined by titration with a standard solution of hydrochloric acid. The pH of the gastrointestinal fluid was measured using a pH test paper and the size and form of the microemulsions were examined under the microscope. 18 healthy rats were randomly divided into three groups, fasted for 24 hours and allowed to drink normally. Three-way pipes were placed at the gastroduodenal junction in Group I, and at the terminal ileum in Group II. After the intragastric administration of ME-RCA, the stomach contents in Group I, the effluent from the terminal ileum in Group II and discharge from the anus in Group III were collected. The pH values of the gastrointestinal juice were measured by the pH test paper and those of the colon were determined by a universal indicator. These animal experiments were also used to test the effect of MBG-RCA.ResultsMBG-RCA showed a better removal rate of artificial colonic ammonia than ME-RCA (P < 0.05). The decrease in pH value of the artificial small intestinal fluid due to ME-RCA did not occur when MBG-RCA was used. In the simulated gastrointestinal process, MBG-RCA maintained greater stability and released the emulsion (ME-RCA) in the colonic fluid. In the gastrointestinal tract of normal SD rats, ME-RCA decreased in size and lost its stable form after entering the small intestine, while MBG-RCA remained stable and intact emulsion-drops were observed from the anus. Neither substance had any effect on the pH of the stomach or colon of normal rats (partly because normal rats were fasted for 24 hours and allowed to drink normally, which resulted in a low level of ammonia production in the colon). Unlike ME-RCA, MBG-RCA did not reduce the pH of the small intestine.ConclusionsMBG-RCA was more stable in the gastrointestinal tract and more effective at removing colonic ammonia when a higher concentration of ammonia was present. This made it possible to achieve the targeted removal of colonic ammonia and is a promising method to prevent hepatic encephalopathy (HE) in future studies.

Preparation and catalytic activity of Fe alginate gel beads for oxidative degradation of azo dyes under visible light irradiation

Fe alginate gel beads were prepared by adding sodium alginate aqueous solution drop-wise into the FeCl 3 gelling solution using a syringe needle at room temperature, and measured in terms of size, mass and Fe content, then characterized using SEM, XRD, FT-IR, XPS and TGA, respectively. The gel beads were evaluated as the heterogeneous Fenton catalysts for oxidative degradation of two typical azo dyes, Reactive Blue 222 and Acid Black 234 in the presence of H 2O 2 under visible light irradiation. Some important factors affecting the preparation of the beads and their catalytic function such as FeCl 3 concentration, irradiation intensity and pH value were examined. The results indicated that Fe 3+ ions coordinated with oxygen atoms in carboxyl groups from glucose chains of alginates to form the Fe alginate gel beads. And Fe 3+ ion was a central cation that has a coordination number of 6 in the complex. Higher concentration of FeCl 3 solution caused the significant increase in the Fe content of the gel bead during preparation. Fe alginate gel beads showed a great catalytic role in the degradation of the azo dyes in a wide pH range of 3.0–8.0. Moreover, higher Fe content and increasing irradiation intensity could promote the catalytic performance of Fe alginate gel beads.

Use of microbial transglutaminase and sodium alginate in the preparation of restructured fish models using cold gelation: Effect of frozen storage

Changes in physicochemical properties of raw-appearing restructured models made from hake (Merluccius capensis) muscle, using cold gelation technology by addition of sodium alginate and microbial transglutaminase (MTGase), were studied during frozen storage at − 15 °C. Among the more interesting results, addition of MTGase produced more protein aggregation in models processed by muscle homogenization and thus the protein network that formed in the gel was better than in samples with added sodium alginate. All samples presented enhanced changes in mechanical properties such as gel strength in the course of frozen storage. The protein network that formed was better organized as shown by the ultrastructure analysis and by protein aggregation data from the beginning of storage, and as a result Water Binding Capacity was greater in restructured models processed by muscle homogenization. Some of the models studied presented lipid oxidation during frozen storage, slightly more in the ones with MTGase added. The industrial relevance of the present work is to establish bases for using fish fillet trimmings and minced muscle to prepare restructured products that can be commercialized in a raw state and that could also support frozen storage in order to prolong the self-life in the market. The models studied here are not final products but the base with which to prepare them. One possibility of them is to process this kind of products with technologies normally used in whole fish muscle such as smoked fish fillets, carpaccios or marinated products. In addition, these raw restructured products can be commercialized to be cooked as a normal fresh fish fillet or pieces of fillet in a variety of preparations, and also products that contain a high amount of salt. Samples elaborated by binding larger muscle fragments imitate well the original fibrousness of the muscle so that it could be used to elaborate products similar to hamburgers or others that will be fried in batter.

Gluten Gel and Film Properties in the Presence of Cysteine and Sodium Alginate

Wheat flour has an ability of forming dough by mixing with water, which exhibits a rheological property required for making bread. The major protein is gluten, which is a valuable protein material for food industry. In this study, gluten protein gels and films were formed with cysteine and sodium alginate. Adding cysteine improved gel and film properties (stress relaxation behavior, bending strength). The gel containing 0.01 M cysteine had a longer relaxation time and was more rigid than the gel without cysteine. Although adding sodium alginate to the gluten suspension containing cysteine improved the water-holding ability and homogeneity of the gel network, the film from this gel was more brittle than the gluten film with cysteine alone. Microstructural observations of the gels and films with scanning electron microscopy suggested that water evaporation was more heterogeneous from the gel containing sodium alginate than from the gel with cysteine alone. Fourier transform-infrared (FT-IR) analysis during film formation suggested that the presence of cysteine encourages interaction between gluten molecules and results in intermolecular beta-sheet formation in earlier stages than in the no additive condition. FT-IR results also suggested that the combined effect of sodium alginate and cysteine on the protein secondary structure was remarkably different from that of cysteine alone. Our results suggest that addition of a suitable amount of cysteine (0.01 M) and heat treatment to 80 degrees C during gluten gel and film formation induces a homogenous network in the gel and film by regulating disulfide-sulfide interactions.

Influence of chitosan type on the properties of extruded pellets with low amount of microcrystalline cellulose

The purpose of this research was to study the influence of type of chitosan with different molecular weights, ie, 190 and 419 kDa, on properties of pellets prepared by extrusion/spheronization. The formulations, consisting of acetaminophen as model drug, chitosan, microcrystalline cellulose (MCC), and dibasic calcium phosphate dihydrate with/without sodium alginate, were extruded using a twin-screw extruder and water as the granulating liquid. With 30% wt/wt MCC and no added sodium alginate, spherical pellets were produced containing low and high molecular weight chitosan at a maximum amount of 60% and 40% wt/wt, respectively. With sodium alginate (2.5% wt/wt), pellets with either type of chitosan (60% wt/wt), MCC (17.5% wt/wt), and acetaminophen (20% wt/wt) could be produced indicating an improved pellet-forming ability. Type and amount of chitosan and added sodium alginate affected physical properties of pellets including size, roundness, crushing force, and drug release. Low molecular weight chitosan produced pellets with higher mean diameter, sphericity, and crushing force. Additionally, the pellets made of low molecular weight chitosan and added sodium alginate showed faster drug release in 0.1 N HCl but had slower drug release in pH 7.4 phosphate buffer. This indicated that drug release from pellets could be modified by the molecular weight of chitosan. In conclusion, the molecular weight of chitosan had a major influence on formation, physical properties, and drug release from the obtained pellets.

Effect of addition of sodium alginate on bacterial cellulose production by Acetobacter xylinum

Bacterial cellulose (BC) production by Acetobacter xylinum NUST4.1 was carried out in the shake flask and in a stirred-tank reactor by means of adding sodium alginate (NaAlg) into the medium. When 0.04% (w/v) NaAlg was added in the shake flask, BC production reached 6.0 g/l and the terminal yield of the cellulose was 27% of the total sugar initially added, compared with 3.7 g/l and 24% in the control, respectively. The variation between replicates in all determinations was less than 5%. During the cultivation in the stirred-tank reactor, the addition of NaAlg changed the morphology of cellulose from the irregular clumps and fibrous masses entangled in the internals to discrete masses dispersing into the broth, which indicates that NaAlg hinders formation of large clumps of BC, and enhances cellulose yield. Because the structure of cellulose is changed depending on the culture condition such as additives, structural characteristics of BC produced in the NaAlg-free and NaAlg medium are compared using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD). SEM photographs show some differences in reticulated structures and ribbon width and FT-IR spectra indicate that there is the hydrogen bonding interaction between BC and NaAlg, then X-ray diffraction (XRD) analysis reveals that BC produced with NaAlg-added has a lower crystallinity and a smaller crystalline size. The results show that enhanced yields and modification of cellulose structure occur in the presence of NaAlg.

Tomato pulp as source for the production of lycopene powder containing high proportion of cis-isomers

Cis-isomers of lycopene has been demonstrated to possess higher biological activity than its all-trans form. The objectives of this study were to compare the extraction efficiency and degree of isomerization of lycopene by employing supercritical carbon dioxide (SCD) and solvents, as well as process the lycopene extract into powder containing high proportion of cis-isomers from tomato pulp as source. Results showed that a high yield of lycopene was achieved by SCD at 350 bar and 70 °C, with cis-isomers making up 41.4% of total lycopene. However, with temperature at 80 and 90 °C, the maximum isomerization was accomplished, and cis-lycopene constituted 51.0 and 53.8% of total lycopene, respectively. For solvent extraction, the highest yield of all-trans-lycopene was attained by ethanol–hexane (4/3 v/v) at 25 and 50 °C, whereas the maximum isomerization (47.0% cis-lycopene) occurred at 75 °C. A powder product containing 34.5% cis-isomers of lycopene was obtained by spray-drying, and the total amount of lycopene in spray-dried powder was much greater than that in freeze-dried powder. The maximum yield of lycopene in the powder product could be obtained through processing by adding sodium alginate to the eluate directly after SCD extraction and open-column chromatography with formation of 41.4% cis-lycopene. The method developed in this study may be used for possible commercial production of highly active lycopene powder.

Effects of Added Sodium Alginate on Mechanical Strength of Apatite Cement

Effects of added sodium alginate on the mechanical strength of Biopex, one type of apatite cement, were investigated since sodium alginate addition is very effective for Biopex to acquire anti-washout property. Addition of sodium alginate into the liquid phase of Biopex resulted in a slower transformation to apatitic monolith. As a result, mechanical strength of set Biopex in terms of diametral tensile strength (DTS) decreased when it was hardened in an incubator kept at 37 degrees C and 100% relative humidity for 7 days. However, DTS value increased with increase in the amount of added sodium alginate when the Biopex paste was immersed in 0.9% saline at 37 degrees C for 7 days. Set Biopex with less sodium alginate also showed larger porosity. Based on these findings, we concluded that added sodium alginate was effective in increasing the mechanical strength of Biopex by inhibiting liquid penetration into its paste when it is exposed to body fluids.