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Novel Cyclodextrin Polymer Adsorbents for PFAS Removal
Published in David M. Kempisty, LeeAnn Racz, Forever Chemicals, 2021
Yuhan Ling, Gokhan Barin, Shan Li, Matthew J. Notter
Cyclodextrin polymers are highly stable in multiple aspects of their use. Based on the results from thermogravimetric analysis (TGA), cyclodextrin polymers are thermally stable and can operate at temperatures as high as 300°C, allowing for adaptive uses such as block extrusion. With a rigid polymeric network, cyclodextrin polymers are not subject to aerobic or anaerobic degradation and are not affected by disinfection processes like chlorination. The single step synthesis provides a clean, insoluble, fully polymerized structure that shows no leaching in aqueous environments. Contaminants that are adsorbed onto the media are held in bond without displacement by other contaminants until desorption is triggered by regeneration processes. It is important to note that the variance among general water quality (e.g., pH, total dissolved solids (TDS), Total Organic Carbon (TOC), etc.) has very limited impacts on the adsorption processes of cyclodextrin polymers for PFAS uptake. This superior feature and how it contributes to the consistent performance of cyclodextrin polymers across different water matrices is discussed in detail in the following sections. DEXSORB+ is now certified by NSF International under NSF/ANSI 61 for its compatibility with municipal drinking water treatment.
Improvement of Useful Enzymes by Protein Engineering
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Cyclodextrins (CDs) are closed-ring structures in which six or more glucose units are joined by means of α-1,4-glucosidic bond. According to the number of their glucose units (G6, G7, and G8), they are named a-, and γ-CDs, respectively. They are able to form inclusion complexes with many organic and inorganic molecules, thereby changing the physical and chemical properties of the included compounds. Cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19.), which catalyzes the degradation of starch into cyclodextrin, is produced mainly by Bacillus strains. The CGTase from B. macerans IFO3490 produced α-CD as the major hydrolysis product from starch, whereas thermostable CGTase from B. stearothermophilus N02 produces α- and β-CDs.
Formulation Development of Small-Volume Parenteral Products
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Madhav S. Kamat, Patrick P. DeLuca
Cyclodextrins as Solubilizers: Cyclodextrins are oligomers of glucose produced by enzymatic degradation of starch. The number of α-1,4-linked glucose units determines the classification into alpha, beta, or gamma cyclodextrins having 6, 7, or 8 glucose units, respectively [57–59]. The cyclodextrins exert their solubilizing effect by forming soluble inclusion complexes in aqueous solutions. The cyclodextrins are amphipathic (i.e., the exterior is hydrophilic due to the hydroxy groups oriented on the exterior while the interior is hydrophobic) and can form soluble, reversible inclusion complexes with water-insoluble compounds. The unsubstituted cyclodextrins are too toxic for parental use, but the chemically modified cyclodextrins appear to be innocuous when administered parenterally and have been shown to effectively enhance the solubility of several drugs including steroids and proteins [60,61]. The solubility of alfaxalone, an insoluble anesthetic, was increased by 5,000 times to 19 mg/mL in 20% hydroxy propyl-β-cyclodextrin [62].
Characterization of oil-in-water pickering emulsions stabilized by β-cyclodextrin systems
Published in Journal of Dispersion Science and Technology, 2023
Sophie Piot, Léon Mentink, Anne-Marie Pensé-Lhéritier
Cyclodextrins (CDs) are a group of natural cyclic oligosaccharides consisting of (α-1,4)-linked α-D-glucopyranose units. They are synthetized from starch via the use of enzymes. They are conical molecules with a hydrophilic upper rim (the outer surface) and a lower ring cavity being relatively hydrophobic. Depending on the number of glucopyranoses, cyclodextrins are classified in α-, β- and γ-cyclodextrins respectively composed in 6, 7 and 8 glucose units. Cyclodextrins are of growing interest for their numerous applications and many reference books are now dedicated to them [1–3]. Applications are found in practically all sectors of industry such as in food, pharmaceutics and cosmetics [4]. β-Cyclodextrin (β-CD) is the most studied and most frequently used cyclodextrin because of its higher availability, its higher versatility and its lower cost compared to the other cyclodextrins. β-CD shows complex-forming capacities toward a very large range of therapeutic compounds [5] and fragrances [6]. As other cyclodextrins, the most characteristic feature of the β-CD molecule is its ability to form inclusion compounds with various substances through host-guest inclusion complexes by hydrophobic and Van der Waal’s forces [7].
Microalgae and bio-polymeric adsorbents: an integrative approach giving new directions to wastewater treatment
Published in International Journal of Phytoremediation, 2022
Palak Saket, Mrinal Kashyap, Kiran Bala, Abhijeet Joshi
Enzymatic hydrolysis of starch leads to the formation of cyclic oligosaccharide called cyclodextrins (Bender Myron and Komiyama 2012). The outer hydrophilic surface allows interaction with polar molecules and hydrophobic cavities engage in adsorption of non-polar molecules. Therefore cyclodextrin and cyclodextrin-based adsorbents attracted researchers’ attention for pollutant removal by adsorption or by electrostatic interaction (Taka et al.2017; Barbosa et al.2019). Since pure cyclodextrin has various weaknesses, it has been modified to cyclodextrin derivatives by amidation, esterification and etherification to increase their capability in terms of solubility and stability (Liu et al.2020). These derivatives are synthesized into sponges, films, capsules, nanoparticles, beads, etc. according to the pollutant to be removed (Crini and Morcellet 2002). Qiu et al. (2019) discussed the adsorption efficiency of 3D-β-cyclodextrin/graphene composites for the removal of Hg (II) (0.2–10mg/L) which was found as 96.6%. They have also proved the high stability performance of adsorbents in low concentrations of Hg (II). Polydopamine-based β-cyclodextrin has been utilized for the removal of organic dyes- methylene blue, crystal violet and malachite green showing adsorption capacities to be 582.95, 473.01 and 1174.67mg/g, respectively (Chen et al.2020).
Spray-drying encapsulation of protein hydrolysates and bioactive peptides: Opportunities and challenges
Published in Drying Technology, 2020
Khashayar Sarabandi, Pouria Gharehbeglou, Seid Mahdi Jafari
Cyclodextrins are also oligosaccharides derived from enzymatic conversion of starch. These carriers consist of conical structures with a hydrophilic outer surface and a lipophilic central cavity. Due to these properties, entrapment of various hydrophobic compounds in the internal cavity is feasible.[58] There are three common cyclodextrins with 6, 7 or 8 D-glucopyranosyl residues (α-, β-, and γ-cyclodextrin, respectively) linked in a ring by α-1,4 glycosidic bonds.[61] Cyclodextrins are economical and relatively low-cost carriers that are broadly used in the encapsulation of lipophilic compounds, vitamins, colors, flavors and essential oils.[58] Furthermore, the influence of mixture of β-cyclodextrin and maltodextrin as a carrier on physicochemical, stability, morphology and bitterness of dried wheat protein hydrolysates has been studied by spray-drying technique.[62]