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Microbial Intervention for Degradation of Agricultural Wastes
Published in Rouf Ahmad Bhat, Moonisa Aslam Dervash, Khalid Rehman Hakeem, Khalid Zaffar Masoodi, Environmental Biotechnology, 2022
Tawseef Ahmad Mir, Muatasim Jan, Mir Sajad Rabani
A heteropolysaccharide, pectin is present in cell walls of plants containing α-1,4 linked D-galacturonic acid backbone, that may be methyl-esterified or substituted pectin, which generally contains D-galacturonic acids. In contrast, the hairy portion of pectin has D-galcturonic acid residues backbone that can be disturbed by α-1,2-linked L-rhamnose residues (de Souza, 2013). The residues of rhamnose in the hairy portion of pectin have generally L-arabinose and D-galactose residues long-side chains (de Vries, 2003). Pectin backbone degradation mainly needs polysaccharide lyase. Fungal glycoside hydrolases that are responsible for degradation of pectin backbone actually belong to GH family 28 (Martens-Uzunova and Schaap, 2009). Endo and exo-polygalacturonases of GH28 family usually break the α-1,4-glycoside bonds between α-galacturonic acids. Besides this, for the process of hydrolysis of backbone of pectin GH family, enzymes are required, which may include α-rhamnosidases of GH78, unsaturated glucuronyl hydrolysis of GH88, and also unsaturated rhmnogalacturonan hydrolases of GH105 (Brink and de Vries, 2011). For the degradation of cellulose (Martinez et al., 2008), Trichoderma spp. are famous; whereas, Aspergillus spp. have the capability to produce a number of enzymes to degrade pectin (Martens-Uzunova and Schaap, 2009).
Structure and Biosynthesis of Hemicelluloses
Published in Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel, Hemicelluloses and Lignin in Biorefineries, 2017
Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel
The six-carbon sugars include D-glucose, most abundant sugar in the biosphere.D-mannose, a C2 epimer of D-glucose.D-galactose, a C4 epimer of D-glucose.L-rhamnose (6-deoxy-L-mannose).L-fucose (6-deoxy-L-galactose).D-galacturonic acid, an oxidized form of D-galactose having a carboxylic group at C6; it is the main component of pectins.D-glucuronic acid, an oxidized form of glucose having a carboxylic group at C6, and its 4-O-methyl derivative. A certain proportion of these D-galacturonic and D-glucuronic acids are in the methyl ester form.
Novel Research on Porous Polymers Using High Pressure Technology
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Porous Polymer Science and Applications, 2022
Fernanda Wariss Figueiredo Bezerra, Jhonatas Rodrigues Barbosa, Lucas Cantão Freitas, Marielba de Los Angeles Rodriguez Salazar, Rafael Henrique Holanda Pinto, Giselle Cristine Melo Aires, Raul Nunes de Carvalho Junior, Jorddy Neves da Cruz
Finally, pectin, a biopolymer formed by different esterified residues of galacturonic acid, is found mainly in citrus fruits and some different food residues. Depending on the degree of esterification, pectin is divided into high methoxyl pectin and low methoxyl pectin and still forms high viscosity gels, even at room temperature (Pierce et al. 2020). Pectin can form an intermolecular junction zone through ionic bonds between divalent cations when the pK is equal to or greater than (3–3.5). Porous polymers based on pectin are biodegradable, have a diversified chemical structure and can be modified by various techniques such as oxidation, copolymerization and carboxymethylation, which help to improve structural and mechanical properties (Pierce et al. 2020).
A review of microalgal cell wall composition and degradation to enhance the recovery of biomolecules for biofuel production
Published in Biofuels, 2023
Syafiqah Md Nadzir, Norjan Yusof, Norazela Nordin, Azlan Kamari, Mohd Zulkhairi Mohd Yusoff
The Type 2 microalgal cell wall is a carbohydrate-rich structure composed of a range of polymers, including cellulose, hemicellulose (xylans, mannans, glucuronan, and glucans), pectin, and algaenan [17]. Cellulose is a linear chain of glucose monomers linked via an insoluble β-1,4-glycosidic bond; it is found in plants, algae, and some bacteria. Hemicelluloses are polysaccharide combinations that intertwine closely with cellulose and lignin in plant cell walls [23]. Based on the primary sugar component in the backbone, they are classified as xylans, mannans, or glucans. Pectins are heteropolysaccharides found naturally in the cell walls of microalgae. They are predominantly composed of units of β-1-4 D-galacturonic acid that may or may not be methyl-esterified. Pectins contribute to the firmness and structure of cell tissue by facilitating intercellular adhesion and mechanical resistance of the cell wall, as well as playing an essential role in cell growth [24].
Pistachio hull as an alternative pectin source: its extraction and use in oil in water emulsion system
Published in Preparative Biochemistry & Biotechnology, 2023
Sehra Barış, Aysel Elik, Fahrettin Göğüş, Derya Koçak Yanık
The galacturonic acid (GalA) content of the samples was determined according to Sucheta et al.[26] 200 µl of the diluted pectin solution (0.01%) was mixed with 3 ml concentrated sulfuric acid and allowed to stand for 30 min. Then, the solution was mixed with 100 µl of 0.1% carbazole and incubated at 60 °C for 30 min. The absorbance of the resulted solution was read at 520 nm against water by using a spectrophotometer (Optima, model SP-3000nano, Tokyo, Japan). D-(+)-galacturonic acid solution at various concentrations (0–200 µg/ml) was used to plot a standard curve. The GalA content was calculated by comparison with the standard curve prepared. The analyses were done in triplicate.