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Natural Polysaccharides in Drug Delivery and Biomedical Applications最新文献

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Production of the Polysaccharide Pullulan by Aureobasidium pullulans Cell Immobilization 普鲁兰毛霉细胞固定化生产普鲁兰多糖的研究
Pub Date : 2022-08-09 DOI: 10.3390/polysaccharides3030032
T. West
This review examines the immobilization of A. pullulans cells for production of the fungal polysaccharide pullulan. Pullulan is a water-soluble gum that exists structurally as a glucan consisting primarily of maltotriose units, which has a variety of food, non-food and biomedical applications. Cells can be immobilized by carrier-binding or entrapment techniques. The number of studies utilizing carrier-binding as a method to immobilize A. pullulans cells appears to outnumber the investigations using cell entrapment. A variety of solid supports, including polyurethane foam, sponge, diatomaceous earth, ion-exchanger, zeolite and plastic composite, have been employed to immobilize pullulan-producing A. pullulans cells. The most effective solid support that was used to adsorb the fungal cells was polyurethane foam which produced polysaccharide after 18 cycles of use. To entrap pullulan-producing fungal cells, agents such as polyurethane foam, polyvinyl alcohol, calcium alginate, agar, agarose, carrageenan and chitosan were investigated. Polysaccharide production by cells entrapped in polyurethane foam, polyvinyl alcohol or calcium alginate was highest and the immobilized cells could be reutilized for several cycles. It was shown that the pullulan content of the polysaccharide synthesized by cells entrapped in calcium alginate beads was low, which limits the method’s usefulness for pullulan production. Further, many of the entrapped fungal cells synthesized polysaccharide with a low pullulan content. It was concluded that carrier-binding techniques may be more effective than entrapment techniques for A. pullulans cell immobilization, since carrier-binding is less likely to affect the pullulan content of the polysaccharide being synthesized.
本文综述了固定化普鲁兰细胞生产真菌普鲁兰多糖的研究进展。普鲁兰是一种水溶性胶,结构上以主要由麦芽糖糖单位组成的葡聚糖存在,具有多种食品、非食品和生物医学应用。细胞可以通过载体结合或包埋技术固定化。利用载体结合作为固定普鲁兰细胞的方法的研究数量似乎超过了使用细胞包埋的研究数量。各种固体载体,包括聚氨酯泡沫、海绵、硅藻土、离子交换剂、沸石和塑料复合材料,被用来固定产生普鲁兰的普鲁兰细胞。对真菌细胞的吸附效果最好的固体载体是聚氨酯泡沫,使用18次后产生多糖。为了诱捕产生普鲁兰的真菌细胞,研究了聚氨酯泡沫、聚乙烯醇、海藻酸钙、琼脂糖、卡拉胶和壳聚糖等诱捕剂。包埋在聚氨酯泡沫、聚乙烯醇或海藻酸钙中的细胞多糖产量最高,并且固定化的细胞可以重复利用几个周期。结果表明,海藻酸钙珠包埋细胞合成的多糖中普鲁兰的含量较低,限制了该方法在普鲁兰生产中的应用。此外,许多被包裹的真菌细胞合成的多糖具有低普鲁兰含量。因此,载体结合技术可能比包埋技术更有效地固定化普鲁兰细胞,因为载体结合不太可能影响合成的多糖中普鲁兰的含量。
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引用次数: 3
Reversible Metal Ion/Complex Binding to Chitin Controlled by Ligand, Redox, and Photochemical Reactions and Active Movement of Chitin on Aquatic Arthropods 配体、氧化还原和光化学反应控制的金属离子/配合物与甲壳素的可逆结合以及水生节肢动物甲壳素的主动运动
Pub Date : 2022-07-28 DOI: 10.3390/polysaccharides3030031
S. Fränzle, Felix Blind
There is strong adsorption of metal ions and their complexes to chitin, which depends on both the oxidation and complexation states of many of the said elements (whereas others display chemical reactions detectable via electrochemical methods while being retained by chitin); thus, ad- and desorption at ambient water concentrations (often in the nMol/L range) are controlled by the presence and photochemical properties (concerning Eu and probably U and Ag) of mainly biogenic organic matter (both DOC and POC, and DON). With chitin forming the outer hull of mobile organisms (animals), this biopolymer is expected to take part in metal distribution in aquatic (limnetic and riverine) ecosystems. Having studied the attachment of many different elements to both crayfish and grafted (marine shrimp) chitin, with the highest accumulations observed in Bi, V, Ni, and LREEs, one should consider secondary biochemical transformations which take place at different water and sediment levels. After chitin had been embedded into sediment, methanogenesis (which requires Ni), Bi, and Sb biomethylations and photodesorption in the illuminated water column will occur if there are appropriate organics, causing the vertical separation of Eu from other REEs, at least during the daytime. Eutrophication will enhance both the production and especially the photooxidation rates of organics in water because phosphorylated sugars and lipids are formed quantitatively within min P, which enter water and undergo Eu-mediated photooxidation much more readily. Another biopolymer, gelatin, acts as an inert matrix-enhancing organic photooxidation product via Eu, producing chemical waves, indicating autocatalysis upon light impact. From the redox-related photodesorption of metal analytes from chitin, both sensors and devices for (light-assisted) electrochemical energy conversion are being developed by our workgroup. The electrochemical determination of adsorption thermodynamics on chitin is thus directly linked to its applications in environmental monitoring and technology.
金属离子及其络合物对几丁质有很强的吸附作用,这取决于许多上述元素的氧化和络合状态(而其他元素则通过电化学方法检测到化学反应,同时被几丁质保留);因此,在环境水浓度(通常在nMol/L范围内)下的吸附和解吸受主要生物源有机物(DOC和POC以及DON)的存在和光化学性质(涉及Eu,可能还有U和Ag)的控制。随着几丁质形成活动生物(动物)的外壳,这种生物聚合物有望在水生(湖泊和河流)生态系统中参与金属分布。在研究了许多不同元素在小龙虾和嫁接(海虾)几丁质上的附着,并在Bi、V、Ni和LREEs中观察到最高的积累后,我们应该考虑在不同的水和沉积物水平下发生的二次生化转化。几丁质嵌入沉积物后,如果存在适当的有机物,则会在光照的水柱中发生甲烷生成(需要Ni)、Bi和Sb的生物甲基化和光解吸,导致Eu与其他稀土元素的垂直分离,至少在白天是这样。富营养化将提高水中有机物的产量,特别是光氧化速率,因为磷酸化糖和脂质在min P内定量形成,它们进入水中并更容易进行eu介导的光氧化。另一种生物聚合物,明胶,作为一种惰性基质增强有机光氧化产物,通过Eu,产生化学波,表明光影响下的自催化作用。从甲壳素中金属分析物的氧化还原相关光解吸,我们的工作组正在开发(光辅助)电化学能量转换的传感器和设备。甲壳素吸附热力学的电化学测定直接关系到甲壳素在环境监测和技术中的应用。
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引用次数: 0
A Systematic Review of New Trends in Ionic Liquids Applied to Electrolytes on Polysaccharides 离子液体在多糖电解质中的应用新动向综述
Pub Date : 2022-07-08 DOI: 10.3390/polysaccharides3030030
H. Ornaghi, E. F. Kerche, R. Neves, F. Monticeli, Lucas Dall Agnol
Polysaccharides are formed by a long chain of monosaccharides, with the main function of promoting energetic and structural reserves for plants and animals. They can be applied as a base of electrolytes, using ionic liquids (ILs) as a solvent base. The study of electrolytes is an emerging field, as they are applied as secondary batteries, fuel cells, solar cells, supercapacitors and chemical sensors. They operate stably under extreme conditions, maintaining their high thermal stability. Furthermore, their low cost and environmentally safe character, compared to conventional electrolytes, have attracted considerable attention in the scientific field. ILs are composed entirely of ions and could be potentially applied as solvents. As electrolytes, ILs are environmentally friendly, and their use in combination with polysaccharides leads to a synergic effect. In the present study, a systematic review was performed of all papers published from 2014 to 2022 regarding ILs and polysaccharides through a search of three databases. Due to the large number of results found, only papers about electrolytes were considered and the main findings described. This study allows for easy identification of the most relevant fields of study with respect to ILs and polysaccharides, as well as the main gaps to be explored in the literature.
多糖是由长链单糖组成,主要功能是促进植物和动物的能量和结构储备。它们可以作为电解质的基础,使用离子液体(ILs)作为溶剂基础。电解质的研究是一个新兴的领域,因为它们被应用于二次电池、燃料电池、太阳能电池、超级电容器和化学传感器。它们在极端条件下稳定运行,保持其高热稳定性。此外,与传统电解质相比,其低成本和环境安全的特点引起了科学领域的广泛关注。il完全由离子组成,有可能用作溶剂。作为电解质,il是环保的,它们与多糖结合使用可以产生协同效应。在本研究中,通过对三个数据库的检索,对2014年至2022年发表的关于il和多糖的所有论文进行了系统回顾。由于发现的结果很多,所以只考虑了关于电解质的论文,并描述了主要的发现。这项研究可以很容易地识别出与il和多糖有关的最相关的研究领域,以及文献中有待探索的主要空白。
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引用次数: 2
Polysaccharides: Sources, Characteristics, Properties, and Their Application in Biodegradable Films 多糖:来源、特征、性质及其在生物可降解薄膜中的应用
Pub Date : 2022-06-27 DOI: 10.3390/polysaccharides3030029
E. Díaz-Montes
Biodegradable films emerge as alternative biomaterials to conventional packaging from fossil sources, which, in addition to offering protection and increasing the shelf life of food products, are ecologically sustainable. The materials mostly used in their formulation are based on natural polysaccharides, plasticizing agents, and bioactive components (e.g., antimicrobial agents or antioxidants). The formulation of biodegradable films from polysaccharides and various plasticizers represents an alternative for primary packaging that can be assigned to specific food products, which opens the possibility of having multiple options of biodegradable films for the same product. This review describes the main characteristics of the most abundant polysaccharides in nature and highlights their role in the formulation of biodegradable films. The compilation and discussion emphasize studies that report on the mechanical and barrier properties of biodegradable films when made from pure polysaccharides and when mixed with other polysaccharides and plasticizing agents.
生物可降解薄膜作为替代传统包装的生物材料出现,除了提供保护和增加食品的保质期外,还具有生态可持续性。其配方中主要使用的材料是基于天然多糖、增塑剂和生物活性成分(例如,抗菌剂或抗氧化剂)。由多糖和各种增塑剂制成的可生物降解薄膜的配方代表了一种可分配给特定食品的初级包装的替代方案,这为同一产品提供了多种可生物降解薄膜选择的可能性。本文综述了自然界中最丰富的多糖的主要特性,并重点介绍了它们在生物可降解薄膜制备中的作用。本文的汇编和讨论重点报道了由纯多糖制备的生物可降解膜以及与其他多糖和增塑剂混合制备的生物可降解膜的力学和屏障性能。
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引用次数: 26
Debenzylation of Benzyl-Protected Methylcellulose 苯基保护甲基纤维素的去苄化
Pub Date : 2022-06-22 DOI: 10.3390/polysaccharides3030028
P. Hashemi, Saskia Wenderoth, A. Koschella, T. Heinze, P. Mischnick
Methyl cellulose and its derivatives are widely used in the food industry, cosmetics, and as construction materials. The properties of methyl celluloses (MC) strongly depend on their degrees and positions of substitution. In order to generate MCs with uncommon blocky substitution, we apply fully protected O-benzyl-O-methyl celluloses (BnMC). Such complex polysaccharide derivatives could not be deprotected completely and without shift of the composition by methods usually applied to mono- and oligosaccharides. Therefore, a facile debenzylation method was developed based on photo-initiated free-radical bromination in the presence of hydrobromic acid scavengers followed by alkaline treatment. The reaction proceeds under homogeneous conditions and without the aid of any catalyst. There is no need for expensive equipment, materials, anhydrous reagents, or running the reaction under anhydrous conditions. Reaction parameters were investigated and optimized for successful debenzylation of completely protected BnMC with degrees of methyl substitution (DSMe) around 1.9 (and DSBn around 1.1). Side-product-free and almost complete debenzylation was achieved when 1,2-epoxybutane (0.5 eq./eq. N-bromosuccinimide) and 2,6-di-tert-butylpyridine (0.5 eq./eq. N-bromosuccinimide) were used in the reaction. Furthermore, ATR-IR and 1H NMR spectroscopy confirmed the successful removal of benzyl ether groups. The method was developed to monitor the transglycosylation reaction of the BnMC with permethylated cellulose, for which the deprotection of many small samples in parallel is required. This comprises the determination of the methyl pattern in the glucosyl units by gas-liquid chromatography (GLC), as well as oligosaccharide analysis by liquid chromatography mass spectrometry (LC-MS) after perdeuteromethylation and partial hydrolysis to determine the methyl pattern in the chains. The unavoidable partial chain degradation during debenzylation does not interfere with this analytical application, but, most importantly, the DS and the methyl pattern were almost congruent for the debenzylated product and the original MC, indicating the full success of this approach The presented method provides an unprecedented opportunity for high throughput and parallel debenzylation of complicated glucans, such as BnMC (as a model compound), for analytical purposes. For comparison, debenzylation using Na/NH3 was applied to BnMC and resulted in a completely debenzylated product with a remarkably high recovery yield of 99 mol% and is, thus, the method of choice for synthetic applications, e.g., for the transglycosylation product prepared under the selected conditions in a preparative scale.
甲基纤维素及其衍生物广泛应用于食品工业、化妆品和建筑材料。甲基纤维素(MC)的性质在很大程度上取决于它们的取代度和位置。为了制备具有罕见块取代的纤维素,我们采用了完全保护的o -苄基- o -甲基纤维素(BnMC)。用通常用于单糖和低聚糖的方法,这种复杂的多糖衍生物不可能完全去保护而不改变其组成。因此,在氢溴酸清除剂存在的情况下,开发了一种基于光引发自由基溴化的简易脱苯方法,然后进行碱性处理。反应在均相条件下进行,没有任何催化剂的帮助。不需要昂贵的设备、材料、无水试剂,也不需要在无水条件下进行反应。研究并优化了反应参数,使完全保护的甲基取代度(DSMe)约为1.9 (DSBn约为1.1)的BnMC成功脱苄化。当1,2-环氧丁烷(0.5当量/当量)为甲基时,可实现无副产物和几乎完全的脱苯反应。n -溴琥珀酰亚胺)和2,6-二叔丁基吡啶(0.5当量/当量)。用n -溴琥珀酰亚胺进行反应。此外,ATR-IR和1H NMR证实了苯醚基团的成功去除。该方法用于监测BnMC与过甲基化纤维素的转糖基化反应,该反应需要并行地对许多小样品进行脱保护。这包括用气液色谱法(GLC)测定葡萄糖基单元中的甲基模式,以及在过氘甲基化和部分水解后用液相色谱质谱法(LC-MS)测定低聚糖链中的甲基模式。在脱苯过程中不可避免的部分链降解不会干扰该分析应用,但最重要的是,脱苯产物和原始MC的DS和甲基模式几乎一致,表明该方法的完全成功。该方法为复杂葡聚糖的高通量和平行脱苯提供了前所未有的机会,如BnMC(作为模型化合物),用于分析目的。相比之下,使用Na/NH3对BnMC进行脱苯反应,得到了完全脱苯的产物,回收率高达99 mol%,因此是合成应用的首选方法,例如,在制备规模下在选定条件下制备的转糖基化产物。
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引用次数: 0
Microalgae Polysaccharides: An Alternative Source for Food Production and Sustainable Agriculture 微藻多糖:粮食生产和可持续农业的替代来源
Pub Date : 2022-06-11 DOI: 10.3390/polysaccharides3020027
Juliana Botelho Moreira, B. Vaz, B. B. Cardias, Camila Gonzales Cruz, Ana Claudia Araujo de Almeida, Jorge Alberto Vieira Costa, M. G. Morais
Carbohydrates or polysaccharides are the main products derived from photosynthesis and carbon fixation in the Calvin cycle. Compared to other sources, polysaccharides derived from microalgae are safe, biocompatible, biodegradable, stable, and versatile. These polymeric macromolecules present complex biochemical structures according to each microalgal species. In addition, they exhibit emulsifying properties and biological characteristics that include antioxidant, anti-inflammatory, antitumor, and antimicrobial activities. Some microalgal species have a naturally high concentration of carbohydrates. Other species can adapt their metabolism to produce more sugars from changes in temperature and light, carbon source, macro and micronutrient limitations (mainly nitrogen), and saline stress. In addition to growing in adverse conditions, microalgae can use industrial effluents as an alternative source of nutrients. Microalgal polysaccharides are predominantly composed of pentose and hexose monosaccharide subunits with many glycosidic bonds. Microalgae polysaccharides can be structural constituents of the cell wall, energy stores, or protective polysaccharides and cell interaction. The industrial use of microalgae polysaccharides is on the rise. These microorganisms present rheological and biological properties, making them a promising candidate for application in the food industry and agriculture. Thus, microalgae polysaccharides are promising sustainable alternatives for potential applications in several sectors, and the choice of producing microalgal species depends on the required functional activity. In this context, this review article aims to provide an overview of microalgae technology for polysaccharide production, emphasizing its potential in the food, animal feed, and agriculture sector.
碳水化合物或多糖是卡尔文循环中光合作用和碳固定的主要产物。与其他来源相比,从微藻中提取的多糖具有安全性、生物相容性、可生物降解性、稳定性和多用途性。这些聚合物大分子根据每种微藻呈现出复杂的生化结构。此外,它们还具有乳化特性和生物特性,包括抗氧化、抗炎、抗肿瘤和抗菌活性。有些微藻的碳水化合物浓度很高。其他物种可以通过改变温度和光照、碳源、宏量和微量元素限制(主要是氮)以及生理盐水胁迫来调整其代谢以产生更多的糖。除了在不利条件下生长外,微藻还可以利用工业废水作为营养物质的替代来源。微藻多糖主要由戊糖和己糖单糖亚基组成,具有许多糖苷键。微藻多糖可以是细胞壁的结构成分,可以是能量的储存,也可以是与细胞相互作用的保护性多糖。微藻多糖的工业用途正在增加。这些微生物表现出流变学和生物学特性,使它们在食品工业和农业中具有很好的应用前景。因此,微藻多糖在几个领域的潜在应用是有希望的可持续替代品,而生产微藻种类的选择取决于所需的功能活性。在此背景下,本文综述了微藻多糖生产技术,强调了其在食品、动物饲料和农业领域的潜力。
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引用次数: 25
Ionic Strength of Methylcellulose-Based Films: An Alternative for Modulating Mechanical Performance and Hydrophobicity for Potential Food Packaging Application 甲基纤维素基薄膜的离子强度:潜在食品包装应用中调节机械性能和疏水性的替代方法
Pub Date : 2022-05-20 DOI: 10.3390/polysaccharides3020026
R. R. Silva, C. Marques, T. R. Arruda, Samiris Côcco Teixeira, T. V. de Oliveira, P. Stringheta, Ana Clarissa dos Santos Pires, Nilda de Fátima Ferreira Soares
The growing environmental concern with the inappropriate disposal of conventional plastics has driven the development of eco-friendly food packaging. However, the intrinsic characteristics of polymers of a renewable origin, e.g., poor mechanical properties, continue to render their practical application difficult. For this, the present work studied the influence of ionic strength (IS) from 0 to 500 mM to modulate the physicochemical properties of methylcellulose (MC). Moreover, for protection against biological risks, Nisin-Z was incorporated into MC’s polymeric matrices, providing an active function. The incorporation of salts (LiCl and MgCl2) promoted an increase in the equilibrium moisture content in the polymer matrix, which in turn acted as a plasticizing agent. In this way, films with a hydrophobic surface (98°), high true strain (85%), and low stiffness (1.6 mPa) can be manufactured by addition of salts, modulating the IS to 500 mM. Furthermore, films with an IS of 500 mM, established with LiCl, catalyzed antibacterial activity against E. coli, conferring synergism and extending protection against biological hazards. Therefore, we demonstrated that the IS control of MC dispersion presents a new alternative to achieve films with the synergism of antibacterial activity against Gram-negative bacteria in addition to flexibility, elasticity, and hydrophobicity required in various applications in food packaging.
随着传统塑料的不当处理,日益增长的环境问题推动了环保食品包装的发展。然而,可再生聚合物的固有特性,例如,较差的机械性能,继续使其实际应用变得困难。为此,本文研究了0 ~ 500 mM离子强度(IS)对甲基纤维素(MC)理化性质的影响。此外,为了防止生物风险,Nisin-Z被纳入MC的聚合物基质中,提供了积极的功能。盐(LiCl和MgCl2)的掺入促进了聚合物基质中平衡水分含量的增加,从而起到了增塑剂的作用。通过这种方法,可以通过添加盐,将IS调节到500 mM来制备具有疏水表面(98°)、高真应变(85%)和低刚度(1.6 mPa)的薄膜。此外,用LiCl建立的IS为500 mM的薄膜,催化了对大肠杆菌的抗菌活性,赋予了协同作用并延长了对生物危害的保护。因此,我们证明了IS对MC分散体的控制提供了一种新的选择,以获得具有抗革兰氏阴性菌抗菌活性协同作用的薄膜,此外还具有食品包装中各种应用所需的柔韧性、弹性和疏水性。
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引用次数: 6
Biofunctionalized Nanomaterials: Alternative for Encapsulation Process Enhancement 生物功能化纳米材料:封装过程增强的替代方案
Pub Date : 2022-05-14 DOI: 10.3390/polysaccharides3020025
F. F. Razura-Carmona, A. Pérez-Larios, S. Sáyago-Ayerdi, M. Herrera-Martínez, J. Sánchez-Burgos
In recent years, interest in the development of nanometric materials with specific characteristics has grown; however, there are few scientific contributions that associate encapsulation methodologies and matrices with the particle objective (metabolic directions, type of administration, biological impact, and biocompatibility). This review focuses on describing the benefits and disadvantages of different techniques for designing custom particles and alternatives for the biofunctionalization nanomaterials regarding the biological impact of a nanomaterial with potential use in foods known as nutraceuticals. The study of optical properties, physicochemical factors, and characteristics such as rheological can predict its stability in the application matrix; however, not only should the characterization of a nanocomposite with applications in food be considered, but also the biological impact that it may present.
近年来,人们对具有特定特性的纳米材料的开发越来越感兴趣;然而,很少有科学贡献将包封方法和基质与颗粒目标(代谢方向、给药类型、生物影响和生物相容性)联系起来。这篇综述的重点是描述设计定制颗粒和替代生物功能纳米材料的不同技术的优缺点,以及纳米材料在营养食品中潜在用途的生物影响。通过对其光学性质、理化因素以及流变性等特性的研究,可以预测其在应用基质中的稳定性;然而,不仅要考虑在食品中应用的纳米复合材料的特性,还要考虑它可能带来的生物影响。
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引用次数: 1
Modification of Orange Bagasse with Reactive Extrusion to Obtain Cellulose-Based Materials 反应挤出法改性甘蔗渣制备纤维素基材料
Pub Date : 2022-05-06 DOI: 10.3390/polysaccharides3020024
J. Mantovan, F. Yamashita, S. Mali
Orange bagasse (OB) could be considered a sustainable, renewable, and low-cost biomass for the extraction of cellulose. In this context, reactive extrusion can be considered an excellent, eco-friendly, alternative process for the extraction of cellulose from lignocellulosic materials. Thus, the present study aimed to obtain cellulose-based materials with a reactive extrusion process and also to investigate the impact of pectin on the delignification process. Two groups of samples (OB and depectinizated OB) were submitted to extrusion with sulfuric acid or sodium hydroxide in one-step processes. The cellulose content of extruded materials was highly affected by pectin content in the raw material; the thermal profile (TGA curves) and crystallinity also changed. The cellulose content of modified materials ranged from 18.8% to 58.4%, with a process yield of 30.6% to 79.2%. The alkaline reagent provided the highest cellulose content among all extrusion treatments tested, mainly for OB without pectin. The extrusion process was considered an efficient and promising process for extracting cellulose from citrus residue. Materials produced in this study can be used as sources of cellulose fiber for various products and processes, such as in the food industry, fermentation substrates, or refined applications after subsequent treatments.
橙甘蔗渣(OB)可以被认为是一种可持续的、可再生的、低成本的纤维素提取生物质。在这种情况下,反应挤压可以被认为是从木质纤维素材料中提取纤维素的一种极好的、环保的替代工艺。因此,本研究旨在通过反应挤压工艺获得纤维素基材料,并研究果胶对脱木质素过程的影响。用硫酸或氢氧化钠一步法对两组样品(OB和去脱钾OB)进行挤压。原料中果胶含量对挤出物料的纤维素含量影响较大;热分布(TGA曲线)和结晶度也发生了变化。改性材料的纤维素含量为18.8% ~ 58.4%,工艺收率为30.6% ~ 79.2%。在所有测试的挤压处理中,碱性试剂提供了最高的纤维素含量,主要是不含果胶的OB。挤压法是从柑橘渣中提取纤维素是一种有效且有发展前景的方法。本研究中生产的材料可作为纤维素纤维的来源,用于各种产品和工艺,如食品工业、发酵底物或后续处理后的精制应用。
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引用次数: 2
Low-Denaturazing Glucose Oxidase Immobilization onto Graphite Electrodes by Incubation in Chitosan Solutions 壳聚糖溶液中低变性葡萄糖氧化酶在石墨电极上的固定化
Pub Date : 2022-05-03 DOI: 10.3390/polysaccharides3020023
Mireia Buaki-Sogó, Laura García-Carmona, M. Gil-Agusti, M. García-Pellicer, A. Quijano-López
In this work, glucose oxidase (GOx) has been immobilized onto graphite rod electrodes through an assisted-chitosan adsorption reaching an enzyme coverage of 4 nmol/cm2. The direct and irreversible single adsorption of the Flavine Adenine Dinucleotide (FAD) cofactor has been minimized by electrode incubation in a chitosan (CH) solution containing the enzyme GOx. Chitosan keeps the enzyme structure and conformation due to electrostatic interactions preventing FAD dissociation from the protein envelope. Using chitosan, both the redox cofactor FAD and the protein envelope remain in the active form as demonstrated by the electrochemistry studies and the enzymatic activity in the electrochemical oxidation of glucose up to a concentration of 20 mM. The application of the modified electrodes for energy harvesting delivered a power density of 119 µW/cm2 with a cell voltage of 0.3 V. Thus, chitosan presents a stabilizing effect for the enzyme conformation promoted by the confinement effect in the chitosan solution by electrostatic interactions. Additionally, it facilitated the electron transfer from the enzyme to the electrode due to the presence of embedded chitosan in the enzyme structure acting as an electrical wiring between the electrode and the enzyme (electron transfer rate constant 2.2 s−1). This method involves advantages compared with previously reported chitosan immobilization methods, not only due to good stability of the enzyme, but also to the simplicity of the procedure that can be carried out even for not qualified technicians which enable their easy implementation in industry.
在这项工作中,葡萄糖氧化酶(GOx)通过壳聚糖的辅助吸附固定在石墨棒电极上,达到4 nmol/cm2的酶覆盖率。在含有GOx酶的壳聚糖(CH)溶液中进行电极孵育,使黄嘌呤腺嘌呤二核苷酸(FAD)辅因子的直接不可逆单吸附最小化。壳聚糖通过静电相互作用保持酶的结构和构象,防止FAD从蛋白包膜上解离。使用壳聚糖,电化学研究表明,氧化还原辅助因子FAD和蛋白质包膜都保持活性形式,并且在葡萄糖的电化学氧化中达到20 mM的酶活性。应用改性电极进行能量收集,在0.3 V的电池电压下,功率密度为119 μ W/cm2。由此可见,壳聚糖通过静电作用对壳聚糖溶液中的约束效应促进酶的构象具有稳定作用。此外,由于酶结构中嵌入的壳聚糖作为电极和酶之间的电线,它促进了电子从酶到电极的转移(电子转移速率常数为2.2 s−1)。与以往报道的壳聚糖固定化方法相比,该方法不仅具有良好的酶稳定性,而且操作简单,即使是不合格的技术人员也可以进行,使其易于在工业上实施。
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Natural Polysaccharides in Drug Delivery and Biomedical Applications
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