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Design and Engineering Parameters of Bioreactors for Production of Bioethanol
Published in Ayerim Y. Hernández Almanza, Nagamani Balagurusamy, Héctor Ruiz Leza, Cristóbal N. Aguilar, Bioethanol, 2023
David Francisco Lafuente-Rincón, Inty Omar Hernández-De Lira, Héctor Hernández-Escoto, María Alejandra Sánchez-Muñoz, Héctor Hugo Molina Correa, Cristian Emanuel Gámez-Alvarado, Perla Araceli Meléndez-Hernández, Javier Ulises Hernández-Beltrán
Cellulose is a linear polymer that is composed of D-Glucose subunits linked by β-1,4 glycosidic bonds, which form the cellobiose dimer. This long chain is linked together by hydrogen bonds and van der Waals forces [17]. Cellulose is generally present in crystalline form (80%) which is hardly to hydrolyze and the rest in amorphous form being more susceptible to enzymatic degradation [18]. On the other hand, hemicellulose is a polysaccharide with a lower molecular weight than cellulose and is composed of different sugars forming shorter and branched chains. These sugars can be divided into different groups such as pentoses (D-xylose, L-arabinose), hexoses (D-glucose, D-mannose, D-galactose), hexuronic acids (D-glucuronic acid, 4-O-methyl-glucuronic and D-galacturonic) and deoxyhexoses (rhamnose and fucose). The main chain of a hemicellulose consists of a single unit (homopolymer), such as xylan, or two or more units (heteropolymer), such as glucomannan. Sugars are linked by β-1,4 glycosidic bonds and sometimes by β-1,3 glycosidic bonds. Hemicellulose is amorphous, therefore, the differences in the composition of sugars, the presence of shorter chains and the ramifications of the main chains make the hemicellulose structure easier to hydrolyze than cellulose [19].
Use of Green Chemistry for Extraction of Bioactive Compounds from Vegetal Sources
Published in Aidé Sáenz-Galindo, Adali Oliva Castañeda-Facio, Raúl Rodríguez-Herrera, Green Chemistry and Applications, 2020
Adriana C. Flores-Gallegos, Ramsés Misael Reyes-Reyna, Paloma Almanza-Tovanche, Marisol Rodríguez-Duarte, Gerardo M. González, Raúl Rodríguez-Herrera, J.A. Ascacio-Valdés
Glycosides owe their name to the glycosidic bond that is generated through condensation of a sugar molecule with a molecule that contains a hydroxyl group. Glycosides can be classified into three groups: saponins, cardiac glycosides and cyanogenic glycosides. However, it can also include a fourth group, the glucosinolates, because its structure is very similar to that of the glycosides (Ávalos and Pérez, 2009). Evaluated the presence of alkaloids, cyanogenic glycosides, and saponins in five of the most widely used medicinal plants in Ecuador: Artemisia absinthium, Cnidoscolus aconitifolius, Parthenium hysterophorus Linn, Piper carpunya Ruiz & Pav and Taraxacum officinale. These authors found that extracts from all plant leaves, were positive for saponins, and P. hysterophorus was the specie with the highest content, while the lowest content was found in P. carpunya. On the other hand, on quantification of cyanogenic glycosides, it was discovered that the plant that showed the highest concentration was C. aconitifolius and the one with the lowest concentration was A. absinthium.
Sustainable Green Polymeric Nanoconstructs for Active and Passive Cancer Therapeutics
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Ankit Rochani, Sreejith Raveendran, D. Sakthi Kumar
Cellulose is one of the most abundantly found molecules in nature and produced by plants, animal, and eubacteria. The molecule exists as glucose molecules linked to each other by so-called β(1–4) glycosidic bonds. Like DX, this molecule also has a large number of–OH groups that make intramolecular hydrogen bonding possible between the molecules, which gives it a linear configuration. These intramolecular interactions cause multiple stacking of cellulose molecules that lead to the formation of larger fibrils of size 5–50 nm in diameter. These interactions provide stability to the polymer and give cellulose fibrils a high axial stiffness. Structurally, certain domains of these cellulose fibrils are highly structured (crystalline) and some are disordered (amorphous) in nature. The crystalline domain of the cellulose fibrils is usually extracted as cellulose nanocrystals [63]. Elastic moduli of the nanocrystalline and micro-fibrillar form are 142.5±31.3 and 150.7±28.8 GPa, respectively. Compared to plant cellulose it is stated that bacterial cellulose (BC) is much porous and biocompatible and resembles collagen in physicochemical properties. That makes BC an interesting molecule for drug delivery and tissue engineering applications. Further, BC purified using sodium hydroxide treatment yields endotoxin levels <20 units/device that was found to be acceptable by the USFDA [64]. This indicates that it can be safe for use for intravenous injections.
A comprehensive review of sustainable approaches for synthetic lubricant components
Published in Green Chemistry Letters and Reviews, 2023
Jessica Pichler, Rosa Maria Eder, Charlotte Besser, Lucia Pisarova, Nicole Dörr, Martina Marchetti-Deschmann, Marcella Frauscher
Glycans are complex carbohydrates, linking monosaccharide units through glycosidic bonds, forming linear or branched polymers. They can be either free oligo- or poly-saccharides or bound to proteins (e.g. glycoproteins) and lipids (e.g. glycolipids) (57), and can be found in animals, plants, and fungi (37). As highly functional glycoproteins, so-called mucins, they play a significant part in the field of implant and cartilage wear reduction or prevention, contact lenses, cosmetics, oral salivary (58), synovial fluid (hyaluronan, a glycosaminoglycan) (59), or reducing friction between cornea and eyelid as tear fluid (60,61). In bio-medical application lubricin, a mucin-like glycoprotein lubricin-like synthetic polymers are important boundary lubricants, and naturally occurring alongside hyaluronic acid in the synovial fluid like mucin, lubricin can bind to surfaces and trap water close to the surface, enhancing gliding and reducing friction at the same time (62). Outside the field of bio-tribology, base oils from glycans are not yet studied for their industrial tribological relevance.
Synthesis, characterisation and supercritical fluid chromatography enantioseparation of new liquid crystalline materials
Published in Liquid Crystals, 2020
Magdalena Urbańska, Petra Vaňkátová, Anna Kubíčková, Květa Kalíková
Most often used method for evaluating the optical purity is direct enantioseparation by chromatography with chiral stationary phases (CSPs). Enantiomers form transient diastereomeric complexes with the CSPs via weak non-covalent interactions. The stability of complexes formed by enantiomers of the same compound differs due to the chirality of the stationary phase itself [14]. Thus, the retention times of enantiomers differ and enantioseparation is carried out. CSPs based on derivatised polysaccharides are the most often used, thanks to high success rate in separating a wide range of structurally diverse enantiomers [15]. There are two classes of polysaccharide-based CSPs available—based on either derivatised cellulose or amylose. Cellulose consists of glucose units linked via β(1→4) glycosidic bonds as opposed to amylose linked via α(1→4) glycosidic bonds. This results in different spatial organisation of the chiral selector and different enantioselectivity. CSPs based on the two different polysaccharides often displays complementarity, with one being able to separate enantiomers that could not be resolved on the other one [16,17]. Amylose-based CSP has been successfully employed before in enantioseparation of series of analogous LCs with (methyl)heptyl terminal chain (based on (R,S)-2-octanol) using supercritical fluid chromatography (SFC) [18] and in other cases of enantioseparations of chiral LCs via both SFC and liquid chromatography [19–21].
Carboxymethyl cellulase production optimization from Glutamicibacter arilaitensis strain ALA4 and its application in lignocellulosic waste biomass saccharification
Published in Preparative Biochemistry and Biotechnology, 2018
Chirom Aarti, Ameer Khusro, Paul Agastian
Lignocellulose is a pivotal source of renewable energy consisting of cellulose, which is in fact structurally, and compositionally complex hemicellulose and recalcitrant lignin.[1] Cellulose is the most copious renewable natural homopolysaccharide in the biosphere.[2] The cellulolytic enzymes synergistically act on cellulosic biomass and hydrolyze them into fermentable sugars in order to produce bioethanol. Cellulase is a multi-enzyme system comprised of endo-1,4-β-D-glucanase (EC 3.2.1.4), exo-1,4-β-D-glucanase (EC 3.2.1.91), and β-glucosidase (EC 3.2.1.21). The endoglucanase (carboxymethyl cellulase) randomly attacks β-1,4 bonds in cellulose, producing glucan chains of different lengths, whereas exoglucanase acts on the ends of the cellulose chain and releases β-cellobiose as the end product. β-glucosidase catalyzes the hydrolysis of glycosidic bonds to non-reducing residues in β-D-glucosides and oligosaccharides, thereby releasing glucose.[3] Despite the substantial necessity of cellulase in bioresource technologies, they are also enormously utilized in diversiform bioprocess industries viz. food, wine, brewery, pulp and paper, textile, pharmaceutical, detergent, livestock, and agriculture.[4]