Articoli di riviste: "Alginate"

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Rizfa, Mila Safitri, Ervia Yudiati e Diah Permata Wijayanti. "Improving The Antioxidant Activity of Sodium Alginate from Sargassum sp. by Thermal Heating and Chemical Methods". Jurnal Kelautan Tropis 23, n. 3 (14 novembre 2020): 284–90. http://dx.doi.org/10.14710/jkt.v23i3.8946.

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The relationship between molecular structure and bioactivity was evaluated for sodium alginates obtained under different degradation treatment (raw alginates, heat-treated, and chemical-treated) from Sargassum sp. This study was conducted to identify the antioxidant activities of the degraded sodium alginate from Sargassum sp. compared to raw extract. Raw alginate as the control treatment was dried overnight at 60 °C, while heat-treated was heated raw alginate at 140oC in a laboratory oven (4.5 hours). Two chemical-treated were applied. Raw alginate added hydrogen peroxide and raw alginat with hydrogen peroxide plus ascorbic acid. This treatments were replicated three times. All the parameters were evaluated spectrophotometrically. The spectroscopy results from the degradation methods showed a new absorbance spectra pattern. The FT-IR spectrum revealed that treatment affects the structure of the alginates. Heat treated and chemical treated sodium alginates showed non significantly different on DPPH radical scavenging activity. Meanwhile, the combination of alginate and hydrogen peroxide treatment was at the lowest scavenging ability. Therefore, alginate oligosaccharides (AOS) produced by heating or adding chemical reagents could be considered as a stronger antioxidant than raw alginate, which may be applied in the industry and biomedical

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Adamiak, Katarzyna, e Alina Sionkowska. "State of Innovation in Alginate-Based Materials". Marine Drugs 21, n. 6 (8 giugno 2023): 353. http://dx.doi.org/10.3390/md21060353.

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This review article presents past and current alginate-based materials in each application, showing the widest range of alginate’s usage and development in the past and in recent years. The first segment emphasizes the unique characteristics of alginates and their origin. The second segment sets alginates according to their application based on their features and limitations. Alginate is a polysaccharide and generally occurs as water-soluble sodium alginate. It constitutes hydrophilic and anionic polysaccharides originally extracted from natural brown algae and bacteria. Due to its promising properties, such as gelling, moisture retention, and film-forming, it can be used in environmental protection, cosmetics, medicine, tissue engineering, and the food industry. The comparison of publications with alginate-based products in the field of environmental protection, medicine, food, and cosmetics in scientific articles showed that the greatest number was assigned to the environmental field (30,767) and medicine (24,279), whereas fewer publications were available in cosmetic (5692) and food industries (24,334). Data are provided from the Google Scholar database (including abstract, title, and keywords), accessed in May 2023. In this review, various materials based on alginate are described, showing detailed information on modified composites and their possible usage. Alginate’s application in water remediation and its significant value are highlighted. In this study, existing knowledge is compared, and this paper concludes with its future prospects.

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Ochbaum, Guy, Maya Davidovich-Pinhas e Ronit Bitton. "Tuning the mechanical properties of alginate–peptide hydrogels". Soft Matter 14, n. 21 (2018): 4364–73. http://dx.doi.org/10.1039/c8sm00059j.

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Covalent bonding peptides to alginates is routinely used to tailor alginate's biofunctionality. Here, we investigate the possibility of tuning the mechanical properties of alginate–peptide gels by altering the sequence of the covalently bound peptide.

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Abourehab, Mohammad A. S., Rahul R. Rajendran, Anshul Singh, Sheersha Pramanik, Prachi Shrivastav, Mohammad Javed Ansari, Ravi Manne, Larissa Souza Amaral e A. Deepak. "Alginate as a Promising Biopolymer in Drug Delivery and Wound Healing: A Review of the State-of-the-Art". International Journal of Molecular Sciences 23, n. 16 (12 agosto 2022): 9035. http://dx.doi.org/10.3390/ijms23169035.

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Biopolymeric nanoparticulate systems hold favorable carrier properties for active delivery. The enhancement in the research interest in alginate formulations in biomedical and pharmaceutical research, owing to its biodegradable, biocompatible, and bioadhesive characteristics, reiterates its future use as an efficient drug delivery matrix. Alginates, obtained from natural sources, are the colloidal polysaccharide group, which are water-soluble, non-toxic, and non-irritant. These are linear copolymeric blocks of α-(1→4)-linked l-guluronic acid (G) and β-(1→4)-linked d-mannuronic acid (M) residues. Owing to the monosaccharide sequencing and the enzymatically governed reactions, alginates are well-known as an essential bio-polymer group for multifarious biomedical implementations. Additionally, alginate’s bio-adhesive property makes it significant in the pharmaceutical industry. Alginate has shown immense potential in wound healing and drug delivery applications to date because its gel-forming ability maintains the structural resemblance to the extracellular matrices in tissues and can be altered to perform numerous crucial functions. The initial section of this review will deliver a perception of the extraction source and alginate’s remarkable properties. Furthermore, we have aspired to discuss the current literature on alginate utilization as a biopolymeric carrier for drug delivery through numerous administration routes. Finally, the latest investigations on alginate composite utilization in wound healing are addressed.

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Putri, Tansza S., Deviyanti Pratiwi, Eddy, Rosalina Tjandrawinata, Dewi L. Margaretta, Florencia L. Kurniawan e Octarina. "Pengaruh suhu air terhadap setting time dari bahan cetak alginat". e-GiGi 12, n. 1 (1 settembre 2023): 74–78. http://dx.doi.org/10.35790/eg.v12i1.47105.

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Abstract: Irreversible hydrocolloid impression materials or alginate is commonly used in dental practice. Its setting time range is 1–4.5 minutes. The setting time is affected by several factors such as water temperature mixed with the alginate powder. There are previous studies evaluated the effect of water temperature on the alginate’s setting time, however, the collected data is still minimal. Therefore, this study aimed to evaluate the effect of water temperature on alginate’s setting time on larger scale. There were total of 423 samples divided into three groups: cold, moderate, and warm temperature of water mixed with alginate; each group consisted of 141 samples. Differences in setting times of the qroups were analyzed with the Kruskal-Wallis test and the Tukey’s HSD. Alginate powder used in this study was the normal-set type. Mixing the alginate powder with water was performed as the factory instruction, and then the mixture was poured into molds and the setting times were measured. The results showed that the setting times of the three groups were significantly different. Group I (cold) had the highest setting time (211 seconds), followed by Group II (room temperature) which was 147 seconds, and Group III (warm) had a setting time of 106 seconds. In conclusion, water temperature has an effect on setting time, that is, the higher the temperature, the faster the setting time, and vice versa. Keywords: alginate; irreversible hydrocolloid; setting time; water temperature Abstrak: Bahan cetak hidrokoloid ireversibel atau alginat merupakan bahan umum yang digunakan di praktek kedokteran gigi, dan memiliki setting time antara 1–4,5 menit. Setting time ditentukan oleh beberapa faktor di antaranya suhu air yang digunakan dalam mencampur bahan cetak tersebut. Terdapat penelitian-penelitian terdahulu yang mengevaluasi efek suhu terhadap setting time, namun data yang dikumpulkan masih minimal. Penelitian ini bertujuan untuk mengetahui efek suhu terhadap setting time bahan cetak alginat dalam skala besar. Terdapat tiga kelompok penelitian yaitu menggunakan suhu air yang dicampurkan dengan alginat dingin, sedang (suhu ruang), dan hangat. Besar sampel penelitian ini ialah 141 sampel per kelompok, sehingga total sampel ialah 423 sampel. Perbandingan setting time dari tiga kelompok kemudian dianalisis secara statistik menggunakan uji Kruskal-Wallis dan Tukey’s HSD untuk mengetahui ada tidaknya perbedaan bermakna dari kelompok-kelompok tersebut. Bubuk alginat yang digunakan merupakan alginat tipe normal. Pencampuran bubuk alginat dengan air dilakukan sesuai dengan instruksi pabrik. Adonan yang telah diaduk dituang ke dalam cetakan dan dilakukan pengukuran setting time. Hasil penelitian mendapatkan setting time dari ketiga kelompok berbeda secara bermakna. Kelompok I (dingin) memiliki setting time tertinggi yaitu selama 211 detik, diikuti kelompok II (sedang) selama 147 detik, dan kelompok III (hangat) selama 106 detik. Simpulan penelitian ini ialah suhu air memiliki efek terhadap setting time, yaitu semakin tinggi suhu air maka semakin singkat setting time, demikian pula sebaliknya. Kata kunci: alginat; hidrokoloid ireversibel; setting time; suhu air

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Fischer, Melissa, Florian Gebhard, Timo Hammer, Christian Zurek, Guido Meurer, Christoph Marquardt e Dirk Hoefer. "Microbial alginate dressings show improved binding capacity for pathophysiological factors in chronic wounds compared to commercial alginate dressings of marine origin". Journal of Biomaterials Applications 31, n. 9 (29 marzo 2017): 1267–76. http://dx.doi.org/10.1177/0885328217702173.

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Marine alginates are well established in wound management. Compared with different modern wound dressings, marine alginates cannot prove superior effects on wound healing. Alginates from bacteria have never been studied for medical applications so far, although the microbial polymer raises expectations for improved binding of wound factors because of its unique O-acetylation. Due to its possible positive effects on wound healing, alginates from bacteria might be a superior future medical product for clinical use. To prove the binding capacity of microbial alginates to pathophysiological factors in chronic wounds, we processed microbial alginate fibres, produced from fermentation of the soil bacterium Azotobacter vinelandii ATCC 9046, into needle web dressings and compared them with commercial dressings made of marine alginate. Four dressings were assessed: Marine alginate dressings containing either ionic silver or zinc/manganese/calcium, and microbial alginate dressings with and without nanosilver. All dressings were tested in an in vitro approach for influence on chronic wound parameters such as elastase, matrix metalloproteases-2, tumour necrosis factor-α, interleukin-8, and free radical formation. Despite the alginate origin or addition of antimicrobials, all dressings were able to reduce the concentration of the proinflammatory cytokines TNF-α and IL-8. However, microbial alginate was found to bind considerable larger amounts of elastase and matrix metalloproteases-2 in contrast to the marine alginate dressings. The incorporation of zinc, silver or nanosilver into alginate fibres did not improve their binding capacity for proteases or cytokines. The addition of nanosilver slightly enhanced the antioxidant capacity of microbial alginate dressings, whereas the marine alginate dressing containing zinc/manganese/calcium was unable to inhibit the formation of free radicals. The enhanced binding affinity by microbial alginate of Azotobacter vinelandii to pathophysiological factors may be interesting to support optimal conditions for wound healing.

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Wibowo, Agung Ari, Ade Sonya Suryandari, Eko Naryono, Vania Mitha Pratiwi, Muhammad Suharto e Naila Adiba. "Encapsulation of Clove Oil within Ca-Alginate-Gelatine Complex: Effect of Process Variables on Encapsulation Efficiency". Jurnal Teknik Kimia dan Lingkungan 5, n. 1 (29 aprile 2021): 71. http://dx.doi.org/10.33795/jtkl.v5i1.214.

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Karena memiliki khasiat seperti analgesik, minyak cengkeh biasa digunakan sebagai obat, antibakteri, antioksidan, dan antimikroba. Kemungkinan enkapsulasi minyak cengkeh sebagai makrokapsul padat dipelajari dengan pembuatan makrokapsul Ca-Alginate-Gelatine. Variabel proses yang digunakan adalah variasi konsentrasi alginat 1% dan 1,5% b / v, dan perbandingan massa antara alginat-gelatin divariasikan antara 1: 4, 1: 6, dan 1: 8 w /w. Selain itu, variasi konsentrasi CaCl2 (10%, 20% dan 30% w / v) sebagai cross-linking agent pembentukan kompleks Ca-Alginate juga digunakan sebagai variabel proses. Peningkatan konsentrasi alginat, gelatin dan CaCl2 nampaknya menurunkan efisiensi enkapsulasi karena terbatasnya volume ruang bebas yang terbentuk pada matriks Ca-Alginat-Gelatin. Efisiensi enkapsulasi tertinggi (93,08%) diperoleh pada penggunaan Alginat 1% w / v, dengan perbandingan alginat dengan gelatin 1: 4 dan ikatan silang dalam larutan CaCl2 10% w / v selama 15 menit.Owing to the properties such as analgesic, clove oil is commonly used as medicine, antibacterial, antioxidant, and antimicrobial drugs. The possibility of clove oil encapsulation as a solid macrocapsule was studied by making Ca-Alginate-Gelatine macrocapsules. The process variables used were variations in Alginate concentration of 1% and 1.5% w/v, and the mass ratio between alginate-gelatine was varied between 1: 4, 1: 6, and 1: 8 w/w. In addition, variations in the concentration of CaCl2 (10%, 20% and 30% w/v) as a cross-linking agent for the formation of Ca-Alginate complexes were also used as process variables. The increase of alginate, gelatine and CaCl2 concentration seems to decreased the encapsulation efficiency because of the limitation of the free space volume formed in the Ca-Alginate-Gelatine matrix. The highest encapsulation efficiency (93.08%) was obtained in the use of Alginate 1% w/v, with a ratio of alginate to gelatine 1: 4 and cross-linking in a 10% w/v CaCl2 solution for 15 minutes.

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Rokhati, Nur, Bambang Pramudono, Nyoman Widiasa e Heru Susanto. "KARAKTERISASI FILM KOMPOSIT ALGINAT DAN KITOSAN". Reaktor 14, n. 2 (8 ottobre 2012): 158. http://dx.doi.org/10.14710/reaktor.14.2.158-164.

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CHARACTERIZATION OF ALGINATE AND CHITOSAN COMPOSITE FILM. Due to the specific characteristics of (thin) films, the use of polymer films in various aplications has singnificantly increased. Alginate and chitosan are natural polymers, which have potential as a raw material for the manufacture of composite films. This paper presents the preparation and characterization of alginate, chitosan and chitosan-alginate composite films. The film characterization included permeability test, degree of swelling, mechanical property, morphology (by SEM), and surface chemistry (by FTIR). The results showed that alginate films have a higher permeability and degree of swelling (DS) than chitosan films. Both permeability and DS decreased with increasing concentration for both alginate and chitosan films. DS experiments showed that the films have the highest DS in water followed by ethanol 95% and ethanol >99.9%, respectively. The mechanical strength of chitosan films was larger than alginate films. Alginate-chitosan composite films prepared by layer by layer method showed better characteristics than the composite films prepared by blending of alginate and chitosan solutions. Meningkatnya aplikasi film polimer di berbagai industri tidak terlepas dari keunggulan yang dimiliki. Alginat dan kitosan merupakan polimer alam yang mempunyai potensi sebagai bahan dasar pembuatan film komposit. Pada penelitian ini dilakukan pembuatan dan karakterisasi film komposit berbasis alginat dan kitosan. Karakterisasi film yang dilakukan meliputi uji: permeabilitas, derajat swelling, mekanik, morfologi (dengan SEM), dan struktur kimia permukaan (dengan FTIR). Hasil penelitian menunjukkan bahwa film alginat mempunyai nilai permeabilitas maupun derajat swelling yang lebih tinggi dibanding dengan film kitosan. Baik pada kitosan maupun alginat memberikan fenomena bahwa semakin besar konsentrasi larutan maka semakin kecil nilai permeabilitas maupun derajat swelling, dengan derajat swelling terhadap air adalah yang paling besar kemudian diikuti oleh ethanol teknis (± 95%) dan yang terkecil adalah ethanol PA (> 99,9%). Kekuatan mekanik film kitosan lebih besar dibanding dengan film alginat. Film komposit alginat-kitosan yang dibuat dengan metode layer by layer memberikan karakteristik yang lebih baik dibanding dengan film komposit yang dibuat dengan pencampuran larutan alginat dan larutan kitosan.

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Kulašević, Lazar N. "Alginate: Applications in the modern world". Chemia Naissensis 1, n. 1 (2018): 187–97. http://dx.doi.org/10.46793/chemn1.1.187k.

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Alginate is a natural polysaccharide extracted from the cell walls of brown algae. Thanks to its biocompatibility, biodegradability, nontoxicity, and low cost, this biopolymer is widely applicable across various fields of biomedical science and bioengineering. Alginates are used as a gelling agent in food industry. Alginate hydrogels are an appealing scaffold material because of their resemblance with natural tissues. Consequently, alginates are widely used in tissue engineering and alginate gel beads as transport vehicles in drug delivery systems. Nonetheless, alginate hydrogels are used in nanotechnology to build artificial capillary blood vessels.

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Sumantri, Dedi, e Prima Suci Waldiatma. "Perbedaan stabilitas dimensi cetakan alginat yang disemprot dan direndam dengan natrium hipoklorit dan ekstrak buah mengkudu: studi eksperimental". Padjadjaran Journal of Dental Researchers and Students 7, n. 3 (2 novembre 2023): 300. http://dx.doi.org/10.24198/pjdrs.v7i3.49983.

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ABSTRAKPendahuluan: Alginat merupakan bahan cetak yang paling umum digunakan pada kedokteran gigi, namun cetakan alginat dapat menjadi media penularan infeksi silang, oleh karena itu perlu didesinfeksi terlebih dahulu. Natrium hipoklorit dan ekstrak buah mengkudu merupakan desinfektan untuk alginat. Alginat mempunyai sifat imbibisi yang mempengaruhi stabilitas dimensi cetakan alginat, sehingga akurasi dan stabilitas dimensi cetakan alginat tetap perlu dipertahankan setelah proses desinfeksi. Tujuan penelitian menganalisis perbandingan stabilitas dimensi cetakan alginat yang direndam dan disemprot dengan natrium hipoklorit 0,5%, ekstrak buah mengkudu 12%, dan ekstrak buah mengkudu 16%. Metode: Penelitian eksperimental laboratorium dengan rancangan post test only group design dengan 12 kelompok uji dan total jumlah sampel 60. Cetakan alginat yang direndam dan disemprot dengan natrium hipoklorit 0,5%, ekstrak buah mengkudu 12%, dan ekstrak buah mengkudu 16% diisi gips, dengan masing-masing diuji pada perbedaan waktu 5 menit dan 10 menit kemudian diukur stabilitas dimensinya menggunakan jangka sorong digital. Data dianalisis dengan Two Way Anova, kemudian uji Post hoc Bonferroni. Hasil: Cetakan alginat yang direndam dengan sodium hipoklorit 0,5%, ekstrak buah mengkudu 12%, dan 16% mengalami perubahan dimensi yang lebih besar dibandingkan dengan yang disemprot dengan menggunakan sodium hipoklorit 0,5%, ekstrak buah mengkudu 12%, dan 16%. Uji Two Way Anova menunjukkan terdapat perbedaan yang signifikan (p<0,05) antara cetakan alginat yang direndam dan disemprot. Simpulan: Terdapat perbedaan stabilitas dimensi antara cetakan alginat yang direndam dan disemprot dengan natrium hipoklorit 0,5%, ekstrak buah mengkudu 12%, dan ekstrak buah mengkudu 16%, selama 5 dan 10 menit.KATA KUNCI: cetakan alginat, desinfeksi, ekstrak buah mengkudu, natrium hipoklorit, stabilitas dimensi.Comparison of dimensional stability between sprayed and immersed alginate impression with sodium hypochlorite and an extract of Morinda citrifolia: an experimental study ABSTRACTIntroduction: Alginate is the most common impression material used in dentistry; however, alginate impression results can be media transmission for cross infection, therefore it is important for disinfection. Sodium hypochlorite and the extract of morinda citrifolia are disinfectants for alginate. Alginate has some characteristics, such as imbibition, that can influence the dimensional stability and accuracy of the alginate impression. The purpose of this study was to determine the difference between the dimensional stability of immersed and sprayed alginate impressions with 0,5% sodium hypochlorite, 12%, and 16% Morinda citrifolia extract, with each tested at a time difference of 5 minutes and 10 minutes. Methods: Laboratory experiment with a posttest-only group design with a total of 60 samples in 12 groups. The alginate impression was immersed and sprayed with 0,5% sodium hypochlorite, 12% extract of Morinda citrifolia, and 16% extract of Morinda citrifolia, filled with gypsum, then measured for the dimensional stability using a digital caliper. Data were analyzed with Two Way Anova test and Post hoc Bonferroni test. Results: The dimension stability of an immersed alginate impression with 0.5% sodium hypochlorite, 12% extract of Morinda citrifolia, and 16% extract of Morinda citrifolia was greater than that of a sprayed alginate impression with 0.5% sodium hypochlorite, 12% extract of Morinda citrifolia, and 16% extract of morinda citrifolia. The Two Way Anova test showed significant difference (p<0,05) between the immersed and sprayed alginate impression. Conclusion: There are differences in the dimensional stability of alginate impression that was immersed and sprayed with 0.5% sodium hypochlorite, 12% extract of Morinda citrifolia, and 16% extract of Morinda citrifolia for 5 and 10 minutes.KEY WORDS: impression alginate, desinfection, extract of morinda citrifolia, sodium hypochlorite, dimensional stability.

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Koti, Basawaraj A., S. Manohar e J. Lalitha. "Media Optimization for Depolymerization of Alginate by Pseudomonas aeruginosa AG LSL-11". International Letters of Natural Sciences 19 (luglio 2014): 30–39. http://dx.doi.org/10.18052/www.scipress.com/ilns.19.30.

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An agar degrading bacterium Pseudomonas aeruginosa AG LSL-11 was acclimatized to alginate for the production of alginase. Production parameters such as pH, temperature, influence of simple carbohydrates and nitrogen sources, and effect of NaCl on growth and alginase production were carried out. Maximum growth was observed at pH 9.0 and 35°C, while alginase was produced optimally at pH 9.0 and 30°C. The alginase produced by Pseudomonas aeruginosa AG LSL-11 was inducible by alginate, and repressed by other simple sugar when supplemented along with alginate in the medium. The bacterium did not require NaCl for growth and production of alginase. The activity staining of partially purified culture supernatant after native PAGE revealed the presence of a single alginase.

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Koti, Basawaraj A., S. Manohar e J. Lalitha. "Media Optimization for Depolymerization of Alginate by Pseudomonas aeruginosa AG LSL-11". International Letters of Natural Sciences 19 (16 luglio 2014): 30–39. http://dx.doi.org/10.56431/p-e5z1l4.

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An agar degrading bacterium Pseudomonas aeruginosa AG LSL-11 was acclimatized to alginate for the production of alginase. Production parameters such as pH, temperature, influence of simple carbohydrates and nitrogen sources, and effect of NaCl on growth and alginase production were carried out. Maximum growth was observed at pH 9.0 and 35°C, while alginase was produced optimally at pH 9.0 and 30°C. The alginase produced by Pseudomonas aeruginosa AG LSL-11 was inducible by alginate, and repressed by other simple sugar when supplemented along with alginate in the medium. The bacterium did not require NaCl for growth and production of alginase. The activity staining of partially purified culture supernatant after native PAGE revealed the presence of a single alginase.

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Muhamad Rahim, Nur Syairah, Norlaily Ahmad e Dzaraini Kamarun. "Preparation and Characterization of Chitosan/Alginate Polyelectrolyte Complex Prepared by Using Calcium Tripolyphosphate Ionic Gelator". Materials Science Forum 857 (maggio 2016): 447–51. http://dx.doi.org/10.4028/www.scientific.net/msf.857.447.

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The formation of polyelectrolyte complexes (PECs) between chitosan and alginate has been widely investigated for many pharmaceutical and biomedical uses. Ionotropic gelation resulted from the crosslinking of polyelectrolytes (PEs) in the presence of ionic crosslinkers to form hydrogels. The most widely used ionic crosslinker for chitosan is sodium tripolyphosphate (NaTPP); and Ca2+ ions for alginates. The use of these cross-linkers to prepare PECs of chitosan and alginates resulted in hydrogels of similar moieties: chitosan-chitosan and alginate-alginate rather than the sought for hybrid chitosan-alginate PECs. Calcium tripolyphosphate (CaTPP) is a single molecule ionic gelator of chitosan and alginate that have the capability of producing the true hybrid compound of chitosan/alginate polyelectrolyte complex. This paper reported the synthesis of calcium tripolyphosphate and the preparation of a hybrid chitosan/alginate PECs using this newly identified ionic gelator. The newly-synthesized ionic gelator was characterized using ICP-OES; the PECs thereof prepared were characterized using TGA and SEM. The degradation temperature of the prepared PECs is higher than the degradation temperatures of the individual chitosan and alginates. SEM image of the prepared PECs showed rougher surfaces compared to the images of the individual chitosan and alginate compound. Both TGA and SEM revealed the possibility of the newly prepared material to be of the PECs sought for.

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Lee, Jin W., e F. Day. "The separation of alginate biosynthesis and acetylation in Pseudomonas syringae". Canadian Journal of Microbiology 44, n. 4 (1 aprile 1998): 394–98. http://dx.doi.org/10.1139/w98-008.

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Seaweed alginate was acetylated by resting cells of Pseudomonas syringae subsp. phaseolicola ATCC 19304. Physiological studies on this strain and its UV-induced mutants showed no correlation between bacterial alginate biosynthesis and acetylation. Specific yields of alginate and degree of acetylation in these polymers varied with strain and culture medium. This was indirect evidence that alginate biosynthesis is separate from polysaccharide acetylation. It indicated that the enzyme system involved in alginate biosynthesis was not directly linked to alginate acetylation and explained why microbial acetylation of seaweed alginates was possible.Key words: resting cell, Pseudomonas syringae, acetylation, bacterial alginate, seaweed alginate.

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Soukaina, Bouissil, EL Alaoui-Talibi Zainab, Pierre Guillaume, Rchid Halima, Michaud Philippe, El Modafar Cherkaoui e Delattre Cédric. "Radical Depolymerization of Alginate Extracted from Moroccan Brown Seaweed Bifurcaria bifurcata". Applied Sciences 10, n. 12 (17 giugno 2020): 4166. http://dx.doi.org/10.3390/app10124166.

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The degradation of alginate extracted from Moroccan Bifurcaria bifurcata has not been fully established to date. In this work, we report the extraction and the characterization of alginate (ASBB) from the brown algae B. bifurcata, as well as the production of oligo-alginates (OGABs) by using a green chemistry process. The depolymerization of ASBB was carried out by controlled radical hydrolysis through our green chemistry process using a hydrogen peroxide (H2O2) catalyst. The molecular weight (Mw) and degree of polymerization (DP) distribution of oligo-alginates (OGABs) obtained were then characterized by HPLC size exclusion chromatography (SEC) and high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Structural characterization revealed that after 6 h of depolymerization of ASBB, we obtained OGABs with Mw ≤ 5.5 kDa and 2 ≤ DP ≤ 24. These results highlight the effectiveness of the controlled radical hydrolysis of alginate to produce good yields of alginate fractions with controlled Mw with a known polymerization degree (DP) and without altering properties of oligo-alginates. Bifurcaria bifurcata can be a potential source of alginate and oligo-alginates given its abundance on the northwest Atlantic coast. The production and characterization of oligo-alginates promote their exploitation in the cosmetic, pharmaceutic, and agriculture fields.

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Jeoh, Tina, Dana E. Wong, Scott A. Strobel, Kevin Hudnall, Nadia R. Pereira, Kyle A. Williams, Benjamin M. Arbaugh, Julia C. Cunniffe e Herbert B. Scher. "How alginate properties influence in situ internal gelation in crosslinked alginate microcapsules (CLAMs) formed by spray drying". PLOS ONE 16, n. 2 (25 febbraio 2021): e0247171. http://dx.doi.org/10.1371/journal.pone.0247171.

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Alginates gel rapidly under ambient conditions and have widely documented potential to form protective matrices for sensitive bioactive cargo. Most commonly, alginate gelation occurs via calcium mediated electrostatic crosslinks between the linear polyuronic acid polymers. A recent breakthrough to form crosslinked alginate microcapsules (CLAMs) by in situ gelation during spray drying (“CLAMs process”) has demonstrated applications in protection and controlled delivery of bioactives in food, cosmetics, and agriculture. The extent of crosslinking of alginates in CLAMs impacts the effectiveness of its barrier properties. For example, higher crosslinking extents can improve oxidative stability and limit diffusion of the encapsulated cargo. Crosslinking in CLAMs can be controlled by varying the calcium to alginate ratio; however, the choice of alginates used in the process also influences the ultimate extent of crosslinking. To understand how to select alginates to target crosslinking in CLAMs, we examined the roles of alginate molecular properties. A surprise finding was the formation of alginic acid gelling in the CLAMs that is a consequence of simultaneous and rapid pH reduction and moisture removal that occurs during spray drying. Thus, spray dried CLAMs gelation is due to calcium crosslinking and alginic acid formation, and unlike external gelation methods, is insensitive to the molecular composition of the alginates. The ‘extent of gelation’ of spray dried CLAMs is influenced by the molecular weights of the alginates at saturating calcium concentrations. Alginate viscosity correlates with molecular weight; thus, viscosity is a convenient criterion for selecting commercial alginates to target gelation extent in CLAMs.

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Fransiska, Dina, Akbar Akbar, Rahmawati Rahmawati e Giyatmi Giyatmi. "KARAKTERISASI NATRIUM ALGINAT DARI BANTEN, LAMPUNG DAN YOGYAKARTA". Jurnal Teknologi Pangan dan Kesehatan (The Journal of Food Technology and Health) 2, n. 2 (5 novembre 2020): 97–104. http://dx.doi.org/10.36441/jtepakes.v2i2.521.

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ABSTRAK: Pada penelitian ini dilakukan studi mengenai ekstraksi alginat dari beberapa lokasi yaitu Banten, Lampung dan Yogyakarta. Hal ini bertujuan untuk menemukan Na-alginat terbaik dari beberapa rumput laut coklat yang ada. Parameter mutu alginate yaitu kadar air, kadar abu dan kadar abu tak larut asam. Hasil analisis didapatkan alginat dengan mutu terbaik berasal dari daerah Yogyakarta dikarenakan memiliki CAW paling tinggi dan impurities paling rendah pada pengujian secara fisik saat berbentuk rumput laut coklat kering dan memiliki rendemen paling banyak, viskositas paling tinggi, kadar air paling rendah, kadar abu dan abu tak larut asam paling rendah pada pengujian fisik dan kimia saat telah manjadi Na-alginat. ABSTRACT: A study was conducted on alginate extraction from several locations, namely Banten, Lampung and Yogyakarta. It aims to find the best Na-alginate from some of the existing brown seaweeds. Alginate quality parameters are moisture content, ash content and acid insoluble ash content. The analysis results obtained that the best quality alginate comes from the Yogyakarta area because it has the highest CAW and the lowest impurities in physical testing when it is in the form of dry brown seaweed and has the most yield, highest viscosity, lowest water content, ash and ash content. acid insoluble was lowest on physical and chemical tests when it was Na-alginate.

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Warashanti, Ni Wayan Florina, Drg Desak Nyoman Ari Susanti e Drg Ni Kd Fiora Rena Pertiwi, M.Biomed. "Perubahan dimensi hasil cetakan alginat setelah perendaman dalam larutan desinfektan rebusan daun alpukat (Persea Americana)". Bali Dental Journal 5, n. 2 (15 novembre 2021): 109–13. http://dx.doi.org/10.51559/bdj.v5i2.74.

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Background: One of the important steps in many dental procedures is an impression. The impression process must be carried out using accurate materials because the impression results must represent the structure of the oral cavity accurately. The material that is widely used is alginate. The process of printing with alginate is one source of cross-infection so that after the alginate is removed from the oral cavity, disinfection must be carried out. Disinfection can be done by soaking in a decoction of avocado leaves. However, the immersion process can cause the alginate mold to change dimensions due to the characteristics of the alginate, namely syneresis and imbibition. Objective: This study aims to determine the effect of immersing alginate molds in avocado leaf stew on changes in dimensions. Methods: The design of this research is Posttest Only Control Group Design. The sample of this research is 36 pieces of gypsum model from alginate mold. Results: based on the results of the analysis using the parametric test (One Way Anova test) it was found that the p value > = 0.05 in all group comparisons, i.e. there was no change in the dimensions of the alginate prints after soaking in the disinfectant ingredients decoction of avocado leaves 25%, 50% , 100% for 5 and 10 minutes. Conclusion: based on the results of this study, it was concluded that immersion in a decoction of 25%, 50%, 100% avocado leaf disinfectant for 5 or 10 minutes did not change the dimensions of the alginate impressions. Latar Belakang: Salah satu tahapan penting dalam banyak prosedur kedokteran gigi adalah pencetakan. Proses pencetakan harus dilakukan menggunakan bahan yang akurat karena hasil cetakan harus merepresentasikan struktur rongga mulut secara akurat. Bahan yang banyak digunakan adalah alginat. Proses pencetakan dengan alginat merupakah salah satu sumber infeksi silang sehingga setelah alginat dikeluarkan dari rongga mulut harus dilakukan desinfeksi. Desinfeksi bisa dilakukan dengan perendaman dalam rebusan daun alpukat. Namun proses perendaman dapat menyebabkan cetakan alginat berubah dimensi akibat sifat khas alginat yaitu sinersis dan imbibisi. Tujuan: penelitian ini bertujuan untuk mengetahui pengaruh perendaman cetakan alginat dalam rebusan daun alpukat terhadap perubahan dimensinya. Metode: Desain penelitian ini adalah Posttest Only Control Group Design. Sampel penelitian ini adalah 36 buah model gipsum dari cetakan alginate. Hasil: berdasarkan hasil analisis menggunakan uji parametric (Uji One Way Anova) didapat bahwa nilai p > α = 0,05 pada semua perbandingan kelompok, yaitu tidak ada perubahan dimensi hasil cetakan alginat setelah direndam dalam bahan desinfektan rebusan daun alpukat 25%, 50%, 100% selama 5 dan 10 menit. Kesimpulan: berdasarkan hasil penelitian ini disimpulkan perendaman dalam bahan desinfektan rebusan daun alpukat 25%, 50%, 100% selama 5 maupun 10 menit tidak menyebabkan perubahan dimensi hasil cetakan alginat.

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Addina, Syahira, Subaryono Subaryono e Sukarno Sukarno. "Aktivitas Oligosakarida Alginat Sebagai Antioksidan dan Inhibitor Alfa glukosidase". Jurnal Pascapanen dan Bioteknologi Kelautan dan Perikanan 15, n. 1 (27 giugno 2020): 47. http://dx.doi.org/10.15578/jpbkp.v15i1.646.

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Oligosakarida alginat (OSA) adalah produk hasil depolimerisasi polimer alginat yang biasanya terdiri dari 2-25 monomer. Produksi OSA dapat dilakukan melalui proses enzimatis, fisik maupun kimiawi. Tujuan penelitian ini adalah mengetahui karakteristik dan bioaktivitas OSA sebagai antioksidan dan inhibitor α-glukosidase. Proses produksi OSA dilakukan secara enzimatis dengan 3 cara penambahan alginat liase yaitu ditambahkan satu kali di awal reaksi (E1), ditambahkan 4 kali dengan interval 2 jam (E2) dan 2 kali interval 4 jam (E3) dengan total volume sama, yaitu 0,15 mL dan aktivitas enzim (1 unit/mL). Total waktu inkubasi adalah 8 jam. Karakterisasi OSA yang dilakukan adalah perhitungan rendemen, analisis profil TLC dan FTIR serta kadar gula pereduksi. Metode DPPH (1,1-diphenyl-2-picrylhydrazyl) digunakan untuk menguji aktivitas antioksidan OSA, sedangkan pengamatan terhadap aktivitas inhibitor α-glukosidase dilakukan dengan melihat aktivitas α-glukosidase dalam mengubah substrat yang diberikan. Hasil penelitian menunjukkan bahwa rendemen OSA dan kadar gula pereduksi tidak berbeda nyata antar perlakuan dengan rendemen OSA berkisar antara 77,29±1,97% hingga 85,46±9,15% dan kadar gula pereduksi OSA berkisar antara 290,32±20,42 µg/mL hingga 312,76±4,74 µg/mL. Aktivitas antioksidan tertinggi diperlihatkan oleh OSA E1 dengan penghambatan terhadap DPPH sebagai radikal bebas sebesar 41,22±2,03% pada konsentrasi 1,2 mg/mL. Aktivitas inhibitor α-glukosidase OSA E1 lebih kecil dibandingkan dengan alginat dengan nilai IC50 masing-masing sebesar 11,23±4,17 ppm dan 5,27±0,29 ppm. Proses depolimerisasi alginat meningkatkan aktivitas alginat sebagai antioksidan namun tidak meningkatkan aktivitasnya sebagai inhibitor α-glukosidase. AbstractAlginate oligosaccharides (AOS) is depolymerization of alginate polymer product that consist of 2-25 monomers. Alginate oligosaccharides can be produced by enzymatic, physical and chemical processes. This research was conducted to find out the characteristics and bioactivity of AOS as an antioxidant and α-glucosidase inhibitor. AOS was produced by enzymatic process with 3 procedures of the addition of the alginate lyase that was added once at the beginning reaction (E1), 4 times every 2 hours (E2) and 2 times every 4 hours (E3) with the same addition of enzyme volume (0.15 mL) and enzyme activity (1 unit/mL). Total incubation times was 8 hours. Alginate oligosaccharides was then characterized their yield, TLC, FTIR profiles and reducing sugar content. DPPH (1,1-diphenyl-2-picrylhydrazyl) method was used to determine antioxidant activity of AOS while observation of α-glucosidase activity in changing the substrate was used to determine inhibitor α-glucosidase activity of AOS. The results showed that yields and reducing sugar level of AOS were not significantly different between treatments. The AOS yields ranged from 77.29±1.97% to 85.46±9.15% and the reducing sugar levels ranged from 290.32±20.42 µg/mL to 312.76±4.74 µg/mL. The highest antioxidant activity was shown by AOS E1 with free radical (DPPH) inhibition of 41.22±2.03%. AOS E1 α-glucosidase inhibitor activity was lower than that of alginate, with the IC50 values of 5.27±0.29 ppm for alginate and 11.23±4.17 ppm for AOS. Depolymerization process of alginates increased antioxidant activity but did not enhance its activity as α-glucosidase inhibitor.

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Milla, Lalita El, Decky J. Indrani e Bambang Irawan. "SINTESIS DAN UJI POROSITAS SCAFFOLD HIDROKSIAPATIT/ALGINAT". ODONTO : Dental Journal 5, n. 1 (10 luglio 2018): 49. http://dx.doi.org/10.30659/odj.5.1.49-53.

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Background: In bone tissue engineering, scaﬀold is required with a large porosity of 80-90%. The porosity of the hydroxyapatite/alginate scaﬀold can be aﬀected by the alginate concentration used. The objective of this study was to determine whether hydroxyapatite/alginate scaﬀolds with alginate concentration of 1% and 3% could be synthesized and to determine whether the use of low concentration alginates in hydroxyapatite/alginate scaﬀolds could increase thescaﬀold porosity.Methods: The method used in making scaﬀold was freeze drying method, while the method used to measure porosity was liquid displacement methodResult: In this study, it was found that hydroxyapatite/1% alginate scaﬀolds porosity had greater porosity compared with hydroxyapatite/3% alginate scaﬀolds with signifcant diﬀerence.Conclusion: So, it can be concluded that the use of lower alginate concentration can increase porosity in hydroxyapatite/alginate scaﬀolds.

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Prasetyaningrum, A., e A. Purbasari. "Ekstraksi Alginate Dari Rumput Laut Dan Aplikasinya Pada Industri". REAKTOR 6, n. 2 (19 giugno 2017): 63. http://dx.doi.org/10.14710/reaktor.6.2.63-67.

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Alginate merupakan komponen utama dari getah alga coklat (Phaeophyceae) yang merupakan senyawa penting dalam dinding sel. Secara kimia alginate merupakan komponen murni dalam asam uronat yang tersusun dalam bentuk rantai linier panjang. Isolasi alginate dari rumput laut coklat dilakukan dengan cara ekstraksi dengan Na2CO3. Pada penelitian ini dilakukan penentuan metode ekstraksi yang paling baik dari ketiga metode yang ada, yaitu metode Vincent, metode Herter, dan metode Bashford. Selanjutnya dilakukan optimasi kondisi operasi yang relative lebih baik untuk melakukan ekstraksi alginat dari rumput laut. Variabel tetap pada proses operasi adalah: jenis rumput laut (Sargassum), suhu, tekanan dan kecepatan pengadukan. Variabel berubah adalah konsentrasi penambahan Na2CO3 (1%, 2%, 3%, 4%, 5%, 6% dan 7% (%w/v)) dan waktu ekstraksi (1; 1,5; 2; 2,5 dan 3 jam). Alginat yang diperoleh kemudian diaplikasikan pada pembuatan es krim untuk mengetahui pengaruh penambahan alginat pada tekstur, warna, Kristal es dan titik beku dari es krim. Dari hasil penelitian diketahui bahwa natrium alginat hasil ekstraksi metode Bashford menghasilkan rendemen yang paling tinggi, yaitu 19,15 gram dari 25 gram sampel. Kondisi ekstraksi yang relative baik untuk ekstraksi ini adalah penambahan Na2CO3 5% dan waktu ekstraksi 2 jam. Untuk aplikasinya, alginat ditambahkan pada produk es krim yang siap dikonsumsi. Es krim yang ditambah alginate 0,2% memiliki tekstur halus, warna lebih merata, kristal es yang lebih lembut dan lebih mudah membeku.Kata kunci : ekstraksi, natrium alginate, es krim

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Bennacef, Chanez, Stéphane Desobry, Jordane Jasniewski, Sébastien Leclerc, Laurent Probst e Sylvie Desobry-Banon. "Influence of Alginate Properties and Calcium Chloride Concentration on Alginate Bead Reticulation and Size: A Phenomenological Approach". Polymers 15, n. 20 (20 ottobre 2023): 4163. http://dx.doi.org/10.3390/polym15204163.

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Two types of alginates, AlgLF and AlgP, were used in this study to produce alginate beads by electro-vibratory extrusion. AlgLF and AlgP exhibited different Mannuronate/Guluronate (M/G) ratios and molecular weights as measured by NMR and SEC-MALS. The calcium chloride concentration was found to have the greatest effect on bead size. Higher concentrations resulted in smaller beads. AlgLF with a higher molecular weight and a lower proportion of G blocks showed smaller beads. For both alginates, the bead size was also influenced by the flow rate and vibration frequency. Alginate solution aging showed a minimal effect. Alginate reticulation was modeled using a mathematical equation. The study provides insights for the optimization of alginate-based materials in different applications by shedding light on the main factors influencing bead size. The importance of the molecular weight, M/G ratio and calcium ion concentration in the gelling process is highlighted, providing opportunities for the tailoring of alginate materials through a phenomenological model.

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Langit, Novita Thea Puspita, Ali Ridlo e Subagiyo Subagiyo. "Pengaruh Konsentrasi Alginat Dengan Gliserol Sebagai Plasticizer Terhadap Sifat Fisik Dan Mekanik Bioplastik". Journal of Marine Research 8, n. 3 (29 agosto 2019): 314–21. http://dx.doi.org/10.14710/jmr.v8i3.25256.

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Munculnya permasalahan lingkungan akibat plastik sintetik mendorong perlunya penelitian bahan kemasan mudah terurai (bioplastik). Salah satu bahan yang tersedia di alam dan berpotensi sebagai pembentuk bioplastik adalah alginat karena mampu membentuk gel. Bioplastik dari alginat memiliki sifat yang tidak fleksibel sehingga perlu ditambah gliserol sebagai plasticizer. Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi alginat dari Sargassum sp. terhadap sifat fisik dan mekanik bioplastik dengan penambahan gliserol dan CaCl2. Materi penelitian ini adalah alginat hasil ekstraksi Sargassum sp. yang diambil dari Perairan Pantai Sundak, Gunung Kidul. Penelitian ini menggunakan metode eksperimental laboratoris yang terdiri dari empat perlakuan konsentrasi alginat (0,5%, 1%, 3% dan 5%) dengan tiga pengulangan. Sifat bioplastik yang diuji meliputi sifat fisik (ketebalan, ketahanan air, kehilangan berat) dan sifat mekanik (kuat tarik dan elongasi). Data yang diperoleh dianalisis menggunakan analisis sidik ragam (ANOVA). Hasil penelitian menunjukkan semakin tinggi konsentrasi alginat akan meningkatkan ketebalan, ketahanan air dan kuat tarik bioplastik namun menurunkan elongasi dan kehilangan berat bioplastik. Konsentrasi alginat berpengaruh terhadap sifat fisik (ketebalan, ketahanan air, kehilangan berat) dan sifat mekanik (kuat tarik kecuali elongasi), konsentrasi alginat terbaik yang memenuhi Japanese Industrial Standard dan standar SNI 7188.7:2016 adalah 0,5% The emergence of environmental problems due to synthetic plastics has led to the need to research biodegradable packaging materials (bioplastics). One of the ingredients available in nature and has the potential to form bioplastics is alginate because it is capable of forming gel. Bioplastic from alginate has inflexible properties so it needs to be added by glycerol as a plasticizer. This research aims to determine the effect of alginate concentration from Sargassum sp. on the physical and mechanical properties of bioplastics with the addition of glycerol and CaCl2. The method of this research is alginate from Sargassum sp. taken from Sundak Beach Waters, Gunung Kidul. This research used a laboratory experimental method consisting of four treatments of alginate concentration (0.5%, 1%, 3% and 5%) with three repetitions. The properties of the bioplastics tested included physical properties (thickness, water resistance, weight loss) and mechanical properties (tensile strength and elongation). Data obtained were analyzed using variance analysis (ANOVA). The results showed that the higher the concentration of alginate would increased thickness, water resistance and tensile strength of bioplastics but decreased the elongation and weight loss of bioplastics. The alginate concentration affects the physical properties (thickness, water resistance, weight loss) and mechanical properties (tensile strength and except elongation), the best alginate concentrations that meet the Japanese Industrial Standard and SNI 7188.7: 2016 are 0.5%

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Ayuni, Ni Putu Sri, Ni Wayan Yuningrat e Ni Wayan Citra. "Kajian Transpor Kreatinin Menggunakan Membran Kitosan-Alginat Tertaut Silang Polivinil Alkohol (PVA)". Jurnal Rekayasa Proses 12, n. 2 (31 dicembre 2018): 56. http://dx.doi.org/10.22146/jrekpros.38401.

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A B S T R A C TThe objective of this research was to determine the efficiency of the creatinine transport using chitosan alginate cross linked by polyvinyl alcohol (PVA) 0.1% with 70, 100, and 130 mg/L of creatinine concentration. The subject of this study was the membranes of chitosan alginate PVA, while the object of this study was the efficiency of the creatinine transport. The PVA 0.1% cross-linking chitosan-alginate membrane (1:0.15) was successfully synthesized. The membrane synthesized was characterized by FTIR, as well as tensile and strain test. The FTIR spectra showed that there is a new peak of the amino group of chitosan and carboxyl group of alginate at ca. 1651 cm-1. The hydroxyl group appears at ca. 1088 cm-1 while ester groups at ca. 1088 cm-1 and ca. 1265 cm-1 which indicate the cross binding between alginate and PVA. The water uptake test of the chitosan alginate PVA membrane reaches 257.76% for 6 hours. The tensile test results of the membrane before and after creatinine transport are 2.77 MPa and 12.56 MPa while the strain tests yield 14.24% and 18.51%, respectively. The maximum efficiency of the creatinine transport using the chitosan-alginate cross linked by PVA is 51.02% at 130 mg/L creatinine. This creatinine transport result using the PVA cross linking chitosan-alginate membrane are more efficient than chitosan-pectin membrane (25.24%) with the same creatinine concentration.Keywords: chitosan-alginate PVA membrane; creatinine; cross-link; synthesis; transportA B S T R A KPenelitian ini bertujuan untuk menentukan nilai efisiensi transpor kreatinin menggunakan membran kitosan-alginat tertaut silang polivinil alkohol (PVA) 0,1% dengan konsentrasi kreatinin 70, 100 dan 130 mg/L. Subjek dalam penelitian ini adalah membran kitosan-alginat PVA, sedangkan objek penelitian ini adalah pengaruh efisiensi transpor pada variasi konsentrasi kreatinin. Membran kitosan alginat (1:0,15) tertaut silang PVA 0,1% telah berhasil disintesis. Karakterisasi membran kitosan-alginat tertaut silang PVA diperoleh untuk spektra FTIR membran menunjukkan bahwa telah terjadi pergeseran serapan gugus amino dari kitosan dan gugus karboksil dari alginat pada puncak sekitar 1651 cm-1. Pada bilangan gelombang 3363,86 cm-1 terdapat serapan gugus –OH serta pada bilangan gelombang sekitar 1088 cm-1 dan 1265 cm-1 berasal dari gugus ester yang menunjukkan ikatan silang antara alginat dan PVA. Hasil uji serapan air pada membran kitosan-alginat PVA selama 6 jam mencapai rata-rata 257,76%. Hasil uji tarik membran sebelum dan setelah transpor masing-masing: 2,77 MPa dan 12,56 MPa dan untuk hasil uji regang membran sebelum dan setelah transpor masing-masing: 14,24% dan 18,51%. Efisiensi transpor kreatinin pada membran kitosan-alginat tertaut silang PVA mencapai efisiensi transpor maksimal pada konsentrasi 130 mg/L (51,02%). Efisiensi transpor kreatinin ini lebih tinggi jika dibandingkan menggunakan membran kitosan-pektin (25,24%) pada konsentrasi yang sama.Kata kunci: kreatinin; membran kitosan-alginat PVA; sintesis; taut silang; transpor

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Nagpal, Ajay, Ranjith Madhavan, Navia George, Niharika R. Thummala e SV Ravi. "Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast—An in vitro Study". Journal of Contemporary Dental Practice 18, n. 11 (2017): 1061–64. http://dx.doi.org/10.5005/jp-journals-10024-2176.

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ABSTRACT Introduction For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. Materials and methods A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with selfdisinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness. Results Difference in surface hardness was statistically insignificant (p > 0.05). Conclusion Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable. Clinical significance Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material. How to cite this article Madhavan R, George N, Thummala NR, Ravi SV, Nagpal A. Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast—An in vitro Study. J Contemp Dent Pract 2017;18(11):1061-1064.

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Yudiati, Ervia, e Alim Isnansetyo. "Characterizing the Three Different Alginate Type of Sargassum siliquosum". ILMU KELAUTAN: Indonesian Journal of Marine Sciences 22, n. 1 (1 marzo 2017): 7. http://dx.doi.org/10.14710/ik.ijms.22.1.7-14.

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This research was aimed to identify the brown seaweed, to characterize the acid, sodium and calcium alginate, and to examine the alginate yield. The identification was done phaenotypically. The extraction method was pretreated by ethanol depigmentation, followed by the extraction of Na2CO3/EDTA and CaCl2 and presipitated with absolute ethanol. The characterization of alginate was done by FT-IR spectroscopy and Thin Layer Chromatography by comparing the samples with standard alginate (Sigma, USA). The key of identification showed that the species was Sargassum siliquosum. There are similarities in signal vibration and TLC spots among the samples and the standard. The TLC test was also showed that those alginates contain mannuronic and guluronic acid. The highest yield was produced by Sodium alginate (40,34% + 0,21), followed by Acid alginate (11,51% + 0,15) and Calcium alginate (4,8% + 0,09). Keywords: alginate, characterization, Sargassum siliquosum, yield

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Miskiyah, Miskiyah, Juniawati Juniawati e Widaningrum Widaningrum. "Optimasi Pati-Alginat sebagai Bahan Pengkapsul Bakteri Probiotik terhadap Karakteristik Beads". Jurnal Aplikasi Teknologi Pangan 9, n. 1 (21 febbraio 2020): 24. http://dx.doi.org/10.17728/jatp.4569.

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Enkapsulasi merupakan proses pembungkusan (coating) suatu bahan inti dengan menggunakan bahan pengkapsul tertentu. Pemanfaatan maltodekstrin, pati sagu, dan maizena sebagai bahan pengkapsul probiotik belum banyak dikembangkan sehingga dapat dijadikan kandidat bahan pengkapsul baru. Tujuan penelitian ini adalah untuk menentukan perbandingan konsentrasi pati-alginat terbaik yang dapat digunakan untuk enkapsulasi probiotik. Rancangan percobaan yang digunakan adalah rancangan faktorial menggunakan 2 faktor, yaitu jenis bahan pengkapsul dan perbandingan konsentrasi bahan pengkapsul. Faktor jenis bahan pengkasul terdiri dari 3 taraf yaitu maltodekstrin-alginat, pati sagu-alginat, dan maizena-alginat, sedangkan faktor konsentrasi bahan pengkapsul terdiri dari 3 taraf yaitu 1:1; 1:2; dan 1:3 (b/b). Hasil penelitian menunjukkan bahwa perbandingan pati-alginat secara bervariasi menghasilkan karakteristik beads dari segi rendemen, diameter beads, dan bentuk beads yang spesifik. Kesimpulannya, bahan pengkapsul probiotik yang terbaik yaitu perbandingan pati:alginat sebesar 1:3.Optimation Starch-alginate for Probiotic Bacteria Encapsulant Based on Beads Characteristic Abstract Encapsulation was known as process of coating a core material using specific materials. The use of maltodextrin, sago starch, and corn starch as a probiotic material for encapsulation has not been widely developed as new material. The aim of the study was to determine the best ratio of starch-alginate concentrations. The experimental design used was factorial design using 2 factors, namely the type of material and the ratio of the concentration. The type of material for encapsulation consisted of: maltodextrin-alginate, sago-alginate starch, and corn starch-alginate, while the concentration was 1:1, 1:2, and 1:3 (w/w). The results showed that the varioys types of materials and concentration provided specific beads characteristic, i.e. yield, beads diameter, and beads shape. As conclusion, the optimum ratio of starch-alginate as probiotic encapsulating could be determined at a ratio of 1:3.

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Dalheim, Marianne Ø., Line Aa Omtvedt, Isabel M. Bjørge, Anita Akbarzadeh, João F. Mano, Finn L. Aachmann e Berit L. Strand. "Mechanical Properties of Ca-Saturated Hydrogels with Functionalized Alginate". Gels 5, n. 2 (19 aprile 2019): 23. http://dx.doi.org/10.3390/gels5020023.

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Abstract (sommario):

In this work, the mechanical properties and stability of alginate hydrogels containing functionalized alginates (peptide and β-cyclodextrin) were studied. There is an increasing interest in the modification of alginates to add functions such as cell attachment and increased solubility of hydrophobic drugs, for better performance in tissue engineering and drug release, respectively. Functionalization was achieved in this study via periodate oxidation followed by reductive amination, previously shown to give a high and controllable degree of substitution. Young’s modulus and the stress at rupture of the hydrogels were in general lowered when exchanging native alginate with the modified alginate. Still, the gel strength could be adjusted by the fraction of modified alginate in the mixed hydrogels as well as the degree of oxidation. No notable difference in deformation at rupture was observed while syneresis was influenced by the degree of oxidation and possibly by the nature and amount of the grafted molecules. The mixed hydrogels were less stable than hydrogels with only native alginate, and modified alginate was released from the hydrogels. Furthermore, the hydrogels in general rather disintegrated than swelled upon saline treatments.

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Rashedy, Sarah H., Mohamed S. M. Abd El Hafez, Mahmoud A. Dar, João Cotas e Leonel Pereira. "Evaluation and Characterization of Alginate Extracted from Brown Seaweed Collected in the Red Sea". Applied Sciences 11, n. 14 (7 luglio 2021): 6290. http://dx.doi.org/10.3390/app11146290.

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Alginates are one of the most important compounds of brown seaweeds. These compounds are employed in the food area, because of their important rheological properties, such as viscosity, gelling, and stabilizing features and as dietary fiber source. In this study, five species of dominant brown seaweeds were collected in the Red Sea (Padina boergesenii, Turbinaria triquetra, Hormophysa cuneiformis, Dictyota ciliolata, and Sargassum aquifolium) so as to characterize the alginate yield and its properties. The analysis demonstrated differences in the alginate yield among the seaweeds. The highest yield of alginate was recorded in the species T. triquetra (22.2 ± 0.56% DW), while the lowest content was observed in H. cuneiformis (13.3 ± 0.52% DW). The viscosity from the alginates varied greatly between the species, whereas the pH varied slightly. The alginate exhibited a moisture content between 6.4 and 13.1%, the ash content ranged between 12.3 and 20% DW, the protein reached values from 0.57 to 1.47% DW, and the lipid concentration varied from 0.3 to 3.5% DW. Thus, the phytochemical analysis demonstrated that the extracted alginates can be safely applied in the food industry. Furthermore, the alginate yield reveals the potential application of these seaweeds as a nutraceutical raw source, which can be exploited by the food industry.

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T., Jayanthy, e Vayyala P. Reddy. "Efficacy of an alginate versus proton pump inhibitor in the symptomatic relief of gastroesophageal reflux symptoms in pregnant women". International Journal of Reproduction, Contraception, Obstetrics and Gynecology 12, n. 6 (26 maggio 2023): 1616–21. http://dx.doi.org/10.18203/2320-1770.ijrcog20231524.

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Abstract (sommario):

Background: Gastroesophageal reflux disease (GERD) is frequently seen during pregnancy with prevalence of 80%. Proton pump inhibitors (PPI) are the most effective drugs used in the treatment of reflux symptoms. Alginates are natural polysaccharide polymer which builds a non-systemic barrier against acid and food reflux in the oesophagus. Aims and objectives were to compare the efficacy of alginate versus PPIs in pregnant women, and to determine the time to onset of decrease in the pain intensity of alginate to PPIs. Methods: This is a prospective randomised study conducted in pregnant women with symptoms of heartburn comparing the efficacy of alginates to PPIs in Kempegowda Institute of Medical Sciences. After subjects have signed the consent, two sachets of 10 ml liquid preparation alginate were given to the alginate group while 40 mg intravenous pantoprazole to the PPI group. Results: Among 40 patients studied, 20 were given alginates and 20 were given PPIs. 7 presented in the 1st trimester and 33 in 2nd trimester. Onset of action is faster with alginates when compared to PPIs, it was 30 min to 1 hour in patients taking alginates and 6-12 hours in patients taking PPIs, duration of action was longer for PPIs than alginates, with alginates it’s observed that it attains 24-hour symptom free interval in shorter time when compared to PPIs. Conclusions: ¬Alginates to be used for rapid symptom relief in patients with acute symptoms as an induction agent, PPIs to be used for longer duration of action as maintenance.

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Elbayomi, Smaher M., Haili Wang, Tamer M. Tamer e Yezi You. "Enhancement of Antioxidant and Hydrophobic Properties of Alginate via Aromatic Derivatization: Preparation, Characterization, and Evaluation". Polymers 13, n. 15 (2 agosto 2021): 2575. http://dx.doi.org/10.3390/polym13152575.

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The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

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Ursini, Ornella, Roberta Angelini, Silvia Franco e Barbara Cortese. "Understanding the metal free alginate gelation process". RSC Advances 11, n. 55 (2021): 34449–55. http://dx.doi.org/10.1039/d1ra06599h.

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Abstract (sommario):

Alginate gelling by ionic cross-linking using multivalent ions has been known and exploited for several decades. We focus on the possibility to obtain alginate hydrogels without using metal cation in order to obtain metal-free alginates hydrogels.

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Kıvılcımdan Moral, Ç., Ö. Doğan e F. D. Sanin. "Use of laboratory-grown bacterial alginate in copper removal". Water Science and Technology 65, n. 11 (1 giugno 2012): 2003–9. http://dx.doi.org/10.2166/wst.2012.101.

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Industrial production leads to toxic heavy metal pollution in water bodies. Copper is one of the examples that requires removal from effluents before being discharged. It is difficult and sometimes very expensive to remove toxic heavy metals by conventional treatment techniques. This study aims to remove copper by the use of bacterial alginate as a non-conventional technique. Bacterial alginates (natural polymers composed of mannuronic and guluronic acid monomers) were synthesized by Azotobacter vinelandii ATCC® 9046 in a laboratory fermentor under controlled environmental conditions. The alginates produced, with a range of different characteristics in terms of monomer distribution and viscosity, were investigated for maximum copper uptake capacities. The average copper uptake capacities of alginates produced were found to be about 1.90 mmol/L Cu2+/g alginate. Although the GG-block amount of alginates was varied from 12 to 87% and culture broth viscosities were changed within the range of 1.47 and 14 cP, neither the block distribution nor viscosities of alginate samples considerably affected the copper uptake of alginates.

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Ridlo, Ali, Sri Sedjati, Endang Supriyantini e Dinda Ayuniar Zanjabila. "Pengembangan Dan Karakterisasi Bioplastik Karagenan-Alginat-Gliserol Dengan Perlakuan Kalsium Klorida". Buletin Oseanografi Marina 12, n. 1 (29 settembre 2022): 43–53. http://dx.doi.org/10.14710/buloma.v12i1.48020.

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Material biopolimer tunggal seperti alginat dan karagenan tidak memiliki sifat fisiko-kimia dan mekanik yang mencukupi untuk digunakan sebagai produk spesifik seperti bioplastik, sehingga diperlukan kombinasi agar diperoleh hidrogel yang lebih kuat dan tahan air. Ion Ca2+ berperan sebagai crosslinker polimer bermuatan negative (alginat dan karagenan) serta meningkatkan struktur jaringan, sifat reologi dan hidrofobisitasnya, dengan cara berikatan silang dengan gugus karboksil alginat daan gugus sulfat karagenaan. Penelitian ini bertujuan untuk mengetahui pengaruh perendaman dalam larutan CaCl2 terhadap karakteristik (ketebalan, keburaman, ketahanan air, biodegradabilitas, kuat tarik dan elongasi) bioplastik alginat-karagenan-gliserol. Alginat diperoleh dari ekstraksi Sargassum sp., sedangkan karagenan diperoleh dari ekstraksi rumput laut K. alvarezii yang berasal dari Jepara, Jawa Tengah. Bioplastik dibuat dengan cara mencampur 1,5 g karagenan dan 0,5 g alginat dalam 146 mL akuades pada suhu 90℃ selama 45 menit, lalu ditambahkan gliserol 2 mL pada suhu 70℃ dan dihomogenkan selama 15 menit, kemudian dicetak pada cetakan gelas dan dikeringkan dalam oven pada suhu 50℃ selama 18 jam. Setelah itu bioplastik dilepas dari cetakannya dan direndam dalam larutan CaCl2 (1%; 2%; 3% dan 4%) selama 5 menit lalu dikeringkan pada suhu ruang. Hasil penelitian menunjukkan bahwa perendaman dalam larutan CaCl2 meningkatkan secara signifikan (p < 0,05) kuat tarik, ketahanan air, dan opacity dan menurunkan ketebalan, elongasi, dan biodegradabilitas bioplastik alginat-karagenan-gliserol. Ketebalan dan kuat tarik bioplastik alginat-karagenan-gliserol yang dihasilkan telah memenuhi Japanese Industrial Standard.Single biopolymer materials such as alginate and carrageenan do not have sufficient physico-chemical and mechanical properties to be used as specific products such as bioplastics, so a combination is needed to obtain stronger and water-resistant hydrogels. The Ca2+ ion acts as a crosslinker for negatively charged polymers (alginate and carrageenan) and improves the network structure, rheological properties and hydrophobicity, by cross-linking with the carboxyl group of alginate and the sulfate group of carrageenan. This study aims to determine the effect of immersion in CaCl2 solution on the characteristics (thickness, opacity, water resistance, biodegradability, tensile strength and elongation at break) of alginate-carrageenan-glycerol bioplastic. Alginate was obtained from the extraction of Sargassum sp., while carrageenan was obtained from the extraction of K. alvarezii seaweed from Jepara, Central Java. Bioplastics were made by mixing 1.5 g of carrageenan and 0.5 g of alginate in 146 mL of distilled water at 90℃ for 45 minutes, then adding 2 mL of glycerol at 70℃ and homogenized for 15 minutes, then molded on a glass mold and dried in the oven at 50℃ for 18 hours. after that, the bioplastic was removed from the mold and immersed in a solution of CaCl2 (1%; 2%; 3% and 4%) for 5 minutes and then dried at room temperature. The results showed that immersion in CaCl2 solution significantly increased (p < 0.05) tensile strength, water resistance, and opacity and decreased thickness, elongation, and biodegradability of alginate-carrageenan-glycerol bioplastics. The thickness and tensile strength of the alginate-carrageenan-glycerol bioplastic produced complies with the Japanese Industrial Standard.

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Song, Yun Ha, Hee Chul Woo e Jaekyoung Lee. "Eco-Friendly Depolymerization of Alginates by H2O2 and High-Frequency Ultrasonication". Clean Technologies 5, n. 4 (6 dicembre 2023): 1402–14. http://dx.doi.org/10.3390/cleantechnol5040069.

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Abstract (sommario):

Marine biomass has attracted attention as an environmentally sustainable energy source that can replace petroleum-based resources. Alginates, the main natural polysaccharides extracted from seaweeds, are used in various fields, such as food, pharmaceuticals, and chemical raw materials. Because the versatile applications of alginates depend on their physicochemical properties, which are controlled by their molecular weights, proper alginate depolymerization should be established. Previous approaches have limitations such as long reaction times and environmental issues. In this study, we report eco-friendly alginate depolymerization using hydrogen peroxide (H2O2)-induced oxidative decomposition and high-frequency ultrasonication. In oxidative decomposition, the depolymerization tendency depends on both the temperature and the use of iron oxide catalysts that can promote the Fenton reaction. Ultrasonication is effective in promoting selective depolymerization and ring-opening reactions. Oligo-alginates obtained through the precise molecular weight regulation of alginate offer potential applications in medical devices and platform chemicals.

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Rodríguez-Montesinos, Y. E., G. Hernández-Carmona e D. L. Arvizu-Higuera. "RECIRCULACIÓN DE LÍQUIDOS RESIDUALES EN LA CONVERSIÓN DE ALGINATO DE CALCIO EN ÁCIDO ALGÍNICO DURANTE EL PROCESO DE PRODUCCIÓN DE ALGINATOS". CICIMAR Oceánides 20, n. 1-2 (31 dicembre 2005): 1. http://dx.doi.org/10.37543/oceanides.v20i1-2.17.

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Abstract (sommario):

Se estudió el efecto de recircular la solución ácida residual en la etapa de conversión de alginato de calcio en ácido algínico, utilizando el alga Macrocystis pyrifera . Los líquidos residuales fueron reciclados en un sistema en contra corriente, con lo cual se logró procesar tres cargas de alginato de sodio con el mismo volumen de agua, permitiendo una conversión efectiva en ácido algínico, con una reducción del 56% en el consumo de agua dulce. Se experimentó un sistema de recirculación en línea (sin reemplazo de agua), este sistema no es recomendable, debido a que la acumulación de calcio en el alginato después de la segunda recirculación, produce una viscosidad aparente muy alta, con un porcentaje de reducció superior al 50%. Se determinó el efecto del número de lavados ácidos del ácido algínico sobre la calidad y rendimiento del alginato obtenido. El tratamiento ácido se llevó a cabo con tres, dos y un lavado. Se concluye que se requieren tres lavados de las fibras de alginato de calcio para lograr una conversión efectiva en ácido algínico, pero el primero y segundo lavado se pueden hacer con ácido reciclado. Es tesis tema representa un ahorro del 66% en el consumo de agua en esta etapa. Recycling of residual liquids from the conversion of calcium alginate to alginic acid during alginate production process The effect of recycling the residual acid solution from the conversion of calcium alginate to alginic acid from the alga Macrocystis pyrifera was studied. The residual liquid was recycled using a counter current system; it was possible to treat three batches of calcium alginate with the same amount of water, with an effective conversion into alginic acid, saving 56% of fresh water. An inline recycling system was experimented (without water replacement). This system is not recommended, because the large increase of calcium in the alginate after the second recycling, produces a very high apparent viscosity. Using this system the viscosity was reduced in more than 50%. We experimented the effect of the number of acid washings of the alginic acid, on the yield and quality of the final alginate. The acid treatment was carried out with three, two and one washing. It was concluded that three acid washings of the calcium alginate fibers are necessary to obtain an effective conversion of calcium alginate to alginic acid, but the first and second washings can be carried out with recycled acid. This system represents a water saving up to 66% in this step.

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Rodríguez-Montesinos, Y. E., G. Hernández-Carmona e D. L. Arvizu-Higuera. "RECIRCULACIÓN DE LÍQUIDOS RESIDUALES EN LA CONVERSIÓN DE ALGINATO DE CALCIO EN ÁCIDO ALGÍNICO DURANTE EL PROCESO DE PRODUCCIÓN DE ALGINATOS". CICIMAR Oceánides 20, n. 1-2 (31 dicembre 2005): 1. http://dx.doi.org/10.37543/oceanides.v20i1-2.17.

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Abstract (sommario):

Se estudió el efecto de recircular la solución ácida residual en la etapa de conversión de alginato de calcio en ácido algínico, utilizando el alga Macrocystis pyrifera . Los líquidos residuales fueron reciclados en un sistema en contra corriente, con lo cual se logró procesar tres cargas de alginato de sodio con el mismo volumen de agua, permitiendo una conversión efectiva en ácido algínico, con una reducción del 56% en el consumo de agua dulce. Se experimentó un sistema de recirculación en línea (sin reemplazo de agua), este sistema no es recomendable, debido a que la acumulación de calcio en el alginato después de la segunda recirculación, produce una viscosidad aparente muy alta, con un porcentaje de reducció superior al 50%. Se determinó el efecto del número de lavados ácidos del ácido algínico sobre la calidad y rendimiento del alginato obtenido. El tratamiento ácido se llevó a cabo con tres, dos y un lavado. Se concluye que se requieren tres lavados de las fibras de alginato de calcio para lograr una conversión efectiva en ácido algínico, pero el primero y segundo lavado se pueden hacer con ácido reciclado. Es tesis tema representa un ahorro del 66% en el consumo de agua en esta etapa. Recycling of residual liquids from the conversion of calcium alginate to alginic acid during alginate production process The effect of recycling the residual acid solution from the conversion of calcium alginate to alginic acid from the alga Macrocystis pyrifera was studied. The residual liquid was recycled using a counter current system; it was possible to treat three batches of calcium alginate with the same amount of water, with an effective conversion into alginic acid, saving 56% of fresh water. An inline recycling system was experimented (without water replacement). This system is not recommended, because the large increase of calcium in the alginate after the second recycling, produces a very high apparent viscosity. Using this system the viscosity was reduced in more than 50%. We experimented the effect of the number of acid washings of the alginic acid, on the yield and quality of the final alginate. The acid treatment was carried out with three, two and one washing. It was concluded that three acid washings of the calcium alginate fibers are necessary to obtain an effective conversion of calcium alginate to alginic acid, but the first and second washings can be carried out with recycled acid. This system represents a water saving up to 66% in this step.

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Prasad. B, Venkata Nagendra, e Latha D. "Investigating the Synergistic Antibacterial Activity of Epiphytic Bacterial Polyketides and Biopolymer Alginates from Marine Microalgae". Journal of University of Shanghai for Science and Technology 23, n. 10 (4 ottobre 2021): 115–35. http://dx.doi.org/10.51201/jusst/21/09704.

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Abstract (sommario):

The objective was framed to analyse the synergistic antibacterial activity and woundhealing ability of the developed polyketide-alginate polymers. Alginates were extracted from a brown seaweed Padina tetrastromatica and used as a synergistic compound along with bacterial polyketides. Polyketides and alginate polymer combinations were used against test bacteria to determine the synergistic antibacterial activity. A novel wound-healing film was developed using polyketide and alginates with synergistic concentrations and its degradability and wound-healing ability was investigated. The findings in the present research showed most significantly that, Staphylococcus aureus showed complete synergy with the mean MIC value of 0.03 μg/ml and with best FIC value of 0.24 (p<0.5). Degradation of developed films revealed that more moisture leads to more release of antibacterial alginate content at the wound site and hence more degradation. This was evident from the FESEM analysis. In vitro wound-healing assay revealed that the developed polyketide-alginate polymers exhibited cell migration and proliferation after 24th hour of incubation at 370C indicating the wound-healing abilities. Hence, it can be concluded that the biochemical compounds present in the developed polyketide-alginate polymers are considered highly significant in treating any types of wounds.

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Badur, Ahmet H., Sujit Sadashiv Jagtap, Geethika Yalamanchili, Jung-Kul Lee, Huimin Zhao e Christopher V. Rao. "Alginate Lyases from Alginate-Degrading Vibrio splendidus 12B01 Are Endolytic". Applied and Environmental Microbiology 81, n. 5 (2 gennaio 2015): 1865–73. http://dx.doi.org/10.1128/aem.03460-14.

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ABSTRACTAlginate lyases are enzymes that degrade alginate through β-elimination of the glycosidic bond into smaller oligomers. We investigated the alginate lyases fromVibrio splendidus12B01, a marine bacterioplankton species that can grow on alginate as its sole carbon source. We identified, purified, and characterized four polysaccharide lyase family 7 alginates lyases, AlyA, AlyB, AlyD, and AlyE, fromV. splendidus12B01. The four lyases were found to have optimal activity between pH 7.5 and 8.5 and at 20 to 25°C, consistent with their use in a marine environment. AlyA, AlyB, AlyD, and AlyE were found to exhibit a turnover number (kcat) for alginate of 0.60 ± 0.02 s−1, 3.7 ± 0.3 s−1, 4.5 ± 0.5 s−1, and 7.1 ± 0.2 s−1, respectively. TheKmvalues of AlyA, AlyB, AlyD, and AlyE toward alginate were 36 ± 7 μM, 22 ± 5 μM, 60 ± 2 μM, and 123 ± 6 μM, respectively. AlyA and AlyB were found principally to cleave the β-1,4 bonds between β-d-mannuronate and α-l-guluronate and subunits; AlyD and AlyE were found to principally cleave the α-1,4 bonds involving α-l-guluronate subunits. The four alginate lyases degrade alginate into longer chains of oligomers.

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40

Zhu, Yuanjia, Charles J. Stark, Sarah Madira, Sidarth Ethiraj, Akshay Venkatesh, Shreya Anilkumar, Jinsuh Jung et al. "Three-Dimensional Bioprinting with Alginate by Freeform Reversible Embedding of Suspended Hydrogels with Tunable Physical Properties and Cell Proliferation". Bioengineering 9, n. 12 (15 dicembre 2022): 807. http://dx.doi.org/10.3390/bioengineering9120807.

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Abstract (sommario):

Extrusion-based three-dimensional (3D) bioprinting is an emerging technology that allows for rapid bio-fabrication of scaffolds with live cells. Alginate is a soft biomaterial that has been studied extensively as a bio-ink to support cell growth in 3D constructs. However, native alginate is a bio-inert material that requires modifications to allow for cell adhesion and cell growth. Cells grown in modified alginates with the RGD (arginine-glycine-aspartate) motif, a naturally existing tripeptide sequence that is crucial to cell adhesion and proliferation, demonstrate enhanced cell adhesion, spreading, and differentiation. Recently, the bioprinting technique using freeform reversible embedding of suspended hydrogels (FRESH) has revolutionized 3D bioprinting, enabling the use of soft bio-inks that would otherwise collapse in air. However, the printability of RGD-modified alginates using the FRESH technique has not been evaluated. The associated physical properties and bioactivity of 3D bio-printed alginates after RGD modification remains unclear. In this study, we characterized the physical properties, printability, and cellular proliferation of native and RGD-modified alginate after extrusion-based 3D bioprinting in FRESH. We demonstrated tunable physical properties of native and RGD-modified alginates after FRESH 3D bioprinting. Sodium alginate with RGD modification, especially at a high concentration, was associated with greatly improved cell viability and integrin clustering, which further enhanced cell proliferation.

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Gao, Shu-Kun, Rui Yin, Xiao-Chen Wang, Hui-Ning Jiang, Xiao-Xiao Liu, Wei Lv, Yu Ma e Yan-Xia Zhou. "Structure Characteristics, Biochemical Properties, and Pharmaceutical Applications of Alginate Lyases". Marine Drugs 19, n. 11 (10 novembre 2021): 628. http://dx.doi.org/10.3390/md19110628.

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Abstract (sommario):

Alginate, the most abundant polysaccharides of brown algae, consists of various proportions of uronic acid epimers α-L-guluronic acid (G) and β-D-mannuronic acid (M). Alginate oligosaccharides (AOs), the degradation products of alginates, exhibit excellent bioactivities and a great potential for broad applications in pharmaceutical fields. Alginate lyases can degrade alginate to functional AOs with unsaturated bonds or monosaccharides, which can facilitate the biorefinery of brown algae. On account of the increasing applications of AOs and biorefinery of brown algae, there is a scientific need to explore the important aspects of alginate lyase, such as catalytic mechanism, structure, and property. This review covers fundamental aspects and recent developments in basic information, structural characteristics, the structure–substrate specificity or catalytic efficiency relationship, property, molecular modification, and applications. To meet the needs of biorefinery systems of a broad array of biochemical products, alginate lyases with special properties, such as salt-activated, wide pH adaptation range, and cold adaptation are outlined. Withal, various challenges in alginate lyase research are traced out, and future directions, specifically on the molecular biology part of alginate lyases, are delineated to further widen the horizon of these exceptional alginate lyases.

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Putri, Arlina Prima, Francesco Picchioni, Sri Harjanto e Mochamad Chalid. "Alginate Modification and Lectin-Conjugation Approach to Synthesize the Mucoadhesive Matrix". Applied Sciences 11, n. 24 (13 dicembre 2021): 11818. http://dx.doi.org/10.3390/app112411818.

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Abstract (sommario):

Alginates are natural anionic polyelectrolytes investigated in various biomedical applications, such as drug delivery, tissue engineering, and 3D bioprinting. Functionalization of alginates is one possible way to provide a broad range of requirements for those applications. A range of techniques, including esterification, amidation, acetylation, phosphorylation, sulfation, graft copolymerization, and oxidation and reduction, have been implemented for this purpose. The rationale behind these investigations is often the combination of such modified alginates with different molecules. Particularly promising are lectin conjugate macromolecules for lectin-mediated drug delivery, which enhance the bioavailability of active ingredients on a specific site. Most interesting for such application are alginate derivatives, because these macromolecules are more resistant to acidic and enzymatic degradation. This review will report recent progress in alginate modification and conjugation, focusing on alginate-lectin conjugation, which is proposed as a matrix for mucoadhesive drug delivery and provides a new perspective for future studies with these conjugation methods.

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43

Tøndervik, Anne, Olav A. Aarstad, Randi Aune, Susan Maleki, Philip D. Rye, Arne Dessen, Gudmund Skjåk-Bræk e Håvard Sletta. "Exploiting Mannuronan C-5 Epimerases in Commercial Alginate Production". Marine Drugs 18, n. 11 (18 novembre 2020): 565. http://dx.doi.org/10.3390/md18110565.

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Alginates are one of the major polysaccharide constituents of marine brown algae in commercial manufacturing. However, the content and composition of alginates differ according to the distinct parts of these macroalgae and have a direct impact on the concentration of guluronate and subsequent commercial value of the final product. The Azotobacter vinelandii mannuronan C-5 epimerases AlgE1 and AlgE4 were used to determine their potential value in tailoring the production of high guluronate low-molecular-weight alginates from two sources of high mannuronic acid alginates, the naturally occurring harvested brown algae (Ascophyllum nodosum, Durvillea potatorum, Laminaria hyperborea and Lessonia nigrescens) and a pure mannuronic acid alginate derived from fermented production of the mutant strain of Pseudomonas fluorescens NCIMB 10,525. The mannuronan C-5 epimerases used in this study increased the content of guluronate from 32% up to 81% in both the harvested seaweed and bacterial fermented alginate sources. The guluronate-rich alginate oligomers subsequently derived from these two different sources showed structural identity as determined by proton nuclear magnetic resonance (1H NMR), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and size-exclusion chromatography with online multi-angle static laser light scattering (SEC-MALS). Functional identity was determined by minimum inhibitory concentration (MIC) assays with selected bacteria and antibiotics using the previously documented low-molecular-weight guluronate enriched alginate OligoG CF-5/20 as a comparator. The alginates produced using either source showed similar antibiotic potentiation effects to the drug candidate OligoG CF-5/20 currently in development as a mucolytic and anti-biofilm agent. These findings clearly illustrate the value of using epimerases to provide an alternative production route for novel low-molecular-weight alginates.

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44

Tiastuti, Kamilla Riska, Mohammad Jusuf Randi e Yan El Rizal Unzilatirrizqy Dewantoro. "Evaluasi sensori dan resistensi es krim jagung kelor dengan penstabil yang berbeda". Journal of Food and Agricultural Product 3, n. 2 (12 ottobre 2023): 69–81. http://dx.doi.org/10.32585/jfap.v3i2.4331.

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Penelitian ini bertujuan untuk mengevaluasi sensori, pH, kadar gula, dan kelelehan es krim yang terbuat dari campuran jagung dan daun kelor dengan penambahan pengstabil alginate, CMC, dan gelatin. Penelitian ini menggunakan rancangan acak lengkap (RAL) pola searah, dimana faktor utamanya adalah jenis pengstabil (alginate, Carboxymethyl cellulose, dan gelatin). Parameter penelitian ini yaitu pH, kadar gula, kelelehan, dan sensori. Penstabil gelatin meningkatkan pH es krim, tetapi lebih rendah daripada pengstabil alginat yang menunjukkan perbedaan signifikan. Penambahan pengstabil CMC meningkatkan kadar gula es krim secara signifikan. Meskipun penggunaan pengstabil CMC atau gelatin tidak signifikan dalam mengurangi kelelehan es krim, penggunaan pengstabil alginat memberikan tekstur yang paling baik, diikuti oleh tanpa pengstabil, CMC, dan gelatin. Terdapat perbedaan signifikan dalam tekstur dan warna es krim, namun tidak ada perbedaan signifikan dalam aroma dan rasa. Kesimpulannya, penggunaan pengstabil alginat mempengaruhi tekstur dan warna es krim jagung kelor, sedangkan aroma dan rasa tidak terpengaruh secara signifikan.Keywords : es krim, jagung, daun kelor, penstabil, alginate, CMC, gelatin, sensori, kelelehan

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45

Štulajterová, R., L. Medvecký, M. Giretová, T. Sopčák e J. Briančin. "Influence of Sodium Alginate on Properties of Tetracalcium Phosphate/Nanomonetite Biocement". Powder Metallurgy Progress 19, n. 1 (1 settembre 2019): 1–11. http://dx.doi.org/10.1515/pmp-2019-0001.

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AbstractThe tetracalcium phosphate/nanomonetite (TTCPMH) biocements with the addition of sodium alginate were prepared by mechanical homogenization of powder mixture with hardening liquid containing sodium alginate. The effect of various viscosity of different alginates on properties of TTCPMH cement mixture was investigated. The medium viscous (MED) alginate had a more negative effect on setting process and compressive strength than low viscous (LOW) alginate. An approx. 50% decrease in mechanical properties (compressive strengths, Young´s modulus, work of fracture (WOF)) was revealed after an addition of 0.25 wt % with rapid fall above 1 wt % of LOW alginate in biocement. A statistically significant difference in the WOF was found between of 0.25 and 0.5 LOW alginate biocements (p<0.035) whereas no statistical differences were revealed between WOF of 0.5 and 1 LOW alginate biocements (p˃0.357). In the microstructure of composite cements, the increased amounts of granular or finer needle-like nanohydroxyapatite particles arranged into the form of more separated spherical agglomerates were observed. A low cytotoxicity of cement extracts based on measurement of cell proliferation was revealed.

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46

Subaryono, Subaryono, Rosmawati Perangiangin, Maggy Thenawidjaja Suhartono e Fransiska Rungkat Zakaria. "Imunomodulator Activity of Alginate Oligosaccharides from Alginate Sargassum crassifolium". Jurnal Pengolahan Hasil Perikanan Indonesia 20, n. 1 (25 aprile 2017): 63. http://dx.doi.org/10.17844/jphpi.v20i1.16434.

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Alginate oligosaccharides (AOS) are oligosaccharides produced from depolimerization of the alginate polymer, and is reported to have various biological activities. The study aims is to determine the effect of AOS production conditions and their effects on products and its activities as an immunomodulatory compound. Production of alginate oligosaccharides (AOS) enzymatically carried out with the help of alginate lyase enzyme produced from the bacterium Bacillus megaterium S245. Variation of incubation time is 2, 4, 6 and 8 hours at concentrations of alginate lyase enzyme addition of 25, 50, 75 and 100U. Treatment of enzyme concentration and the duration of incubation in the production of AOS produces a degree of polymerization (DP) 2-7. In vitro activity test showed AOS is have ability to induce cell proliferation of human lymphocytes. This type of cell lymphocytes proliferation induced by AOS is a CD 8 cells or cytotoxic T cell and non cell CD4 / CD8. AOS production conditions with the addition of alginate lyase enzyme 50 U and incubation period 2 hours has produce AOS with the highest index of lymphocyte proliferation 117.6+3.6% or an increase of 43.24% compared to the native alginat polymer.

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47

Hernández-Gallegos, Minerva Aurora, Javier Solorza-Feria, Maribel Cornejo-Mazón, José Rodolfo Velázquez-Martínez, María Eva Rodríguez-Huezo, Gustavo F. Gutiérrez-López e Humberto Hernández-Sánchez. "Protective Effect of Alginate Microcapsules with Different Rheological Behavior on Lactiplantibacillus plantarum 299v". Gels 9, n. 9 (24 agosto 2023): 682. http://dx.doi.org/10.3390/gels9090682.

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Alginate encapsulation is a well-known technique used to protect microorganisms from adverse conditions. However, it is also known that the viscosity of the alginate is dependent on its composition and degree of polymerization and that thermal treatments, such as pasteurization and sterilization, can affect the structure of the polymer and decrease its protection efficiency. The goal of this study was to evaluate the protective effect of encapsulation, using alginates of different viscosities treated at different temperatures, on Lactiplantibacillus plantarum 299v under in vitro gastrointestinal conditions and cold storage at 4 °C and −15 °C, respectively. Steady- and dynamic-shear rheological tests were used to characterize the polymers. Thermal treatments profoundly affected the rheological characteristics of alginates with high and low viscosity. However, the solutions and gels of the low-viscosity alginate were more affected at a temperature of 117 °C. The capsules elaborated with high-viscosity alginate solution and pasteurized at 63 °C for 30 min provided better protection to the cells of L. plantarum 299v under simulated gastrointestinal and cold storage conditions.

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48

Yin, Rui, Yan-Jun Yi, Zhuo Chen, Bao-Xun Wang, Xue-Han Li e Yan-Xia Zhou. "Characterization of a New Biofunctional, Exolytic Alginate Lyase from Tamlana sp. s12 with High Catalytic Activity and Cold-Adapted Features". Marine Drugs 19, n. 4 (28 marzo 2021): 191. http://dx.doi.org/10.3390/md19040191.

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Alginate, a major acidic polysaccharide in brown algae, has attracted great attention as a promising carbon source for biorefinery systems. Alginate lyases, especially exo-type alginate lyase, play a critical role in the biorefinery process. Although a large number of alginate lyases have been characterized, few can efficiently degrade alginate comprised of mannuronate (M) and guluronate (G) at low temperatures by means of an exolytic mode. In this study, the gene of a new exo-alginate lyase—Alys1—with high activity (1350 U/mg) was cloned from a marine strain, Tamlana sp. s12. When sodium alginate was used as a substrate, the recombinant enzyme showed optimal activity at 35 °C and pH 7.0–8.0. Noticeably, recombinant Alys1 was unstable at temperatures above 30 °C and had a low melting temperature of 56.0 °C. SDS and EDTA significantly inhibit its activity. These data indicate that Alys1 is a cold-adapted enzyme. Moreover, the enzyme can depolymerize alginates polyM and polyG, and produce a monosaccharide as the minimal alginate oligosaccharide. Primary substrate preference tests and identification of the final oligosaccharide products demonstrated that Alys1 is a bifunctional alginate lyase and prefers M to G. These properties make Alys1 a valuable candidate in both basic research and industrial applications.

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49

Hariyadi, Dewi Melani, e Nazrul Islam. "Current Status of Alginate in Drug Delivery". Advances in Pharmacological and Pharmaceutical Sciences 2020 (6 agosto 2020): 1–16. http://dx.doi.org/10.1155/2020/8886095.

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Alginate is one of the natural polymers that are often used in drug- and protein-delivery systems. The use of alginate can provide several advantages including ease of preparation, biocompatibility, biodegradability, and nontoxicity. It can be applied to various routes of drug administration including targeted or localized drug-delivery systems. The development of alginates as a selected polymer in various delivery systems can be adjusted depending on the challenges that must be overcome by drug or proteins or the system itself. The increased effectiveness and safety of sodium alginate in the drug- or protein-delivery system are evidenced by changing the physicochemical characteristics of the drug or proteins. In this review, various routes of alginate-based drug or protein delivery, the effectivity of alginate in the stem cells, and cell encapsulation have been discussed. The recent advances in the in vivo alginate-based drug-delivery systems as well as their toxicities have also been reviewed.

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50

Kıvılcımdan Moral, Çiğdem, e Merve Yıldız. "Alginate Production from Alternative Carbon Sources and Use of Polymer Based Adsorbent in Heavy Metal Removal". International Journal of Polymer Science 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/7109825.

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Alginate is a biopolymer composed of mannuronic and guluronic acids. It is harvested from marine brown algae; however, alginate can also be synthesized by some bacterial species, namely,AzotobacterandPseudomonas. Use of pure carbohydrate sources for bacterial alginate production increases its cost and limits the chance of the polymer in the industrial market. In order to reduce the cost of bacterial alginate production, molasses, maltose, and starch were utilized as alternative low cost carbon sources in this study. Results were promising in the case of molasses with the maximum 4.67 g/L of alginate production. Alginates were rich in mannuronic acid during early fermentation independent of the carbon sources while the highest guluronic acid content was obtained as 68% in the case of maltose. The polymer was then combined with clinoptilolite, which is a natural zeolite, to remove copper from a synthetic wastewater. Alginate-clinoptilolite beads were efficiently adsorbed copper up to 131.6 mg Cu2+/g adsorbent at pH 4.5 according to the Langmuir isotherm model.

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