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Role of Pullulans in Cosmetics
Published in Shakeel Ahmed, Aisverya Soundararajan, Pullulan, 2020
Sudipta Roy, Sanjoy Kumar Das, Soumalya Chakraborty, Kamalendu Pandey, Ahana Mukherjee, Rajan Rajabalaya
The name pullulan was coined by the great scientist Bender, who described the formation of this extracellular polysaccharide by A. pullulans[14]. Pullulan is an anaerobically produced, water-soluble glucan gum from a yeast-like fungus A. pullulans[3]. Three glucose units of maltotriose are linked through α-(1→4) glycosidic bonds, whereas maltotriose units are linked through α-(1→6) bonds[15]. The chemical structure of pullulan is shown in Fig. 10.1. The molecular weight of pullulan has considerable variety, ranging from 4.5 × 104 to 6 × 105 Da[16]. The molecular weights of pullulan vary on the growing environments of the organism A. pullulans[17]. Chemical structure of pullulan. Figure taken from Ref.[18].
Introduction
Published in Jean-Luc Wertz, Bénédicte Goffin, Starch in the Bioeconomy, 2020
Jean-Luc Wertz, Bénédicte Goffin
We depend upon starch for our nutrition, exploit it in industry, and use it as a feedstock for the production of bioethanol. Starch is a major energy source for humans; it is degraded by digestive enzymes, called amylases, into a variety of disaccharides, trisaccharides, and oligosaccharides (dextrins). Amylases are a group of enzymes that hydrolyze glycosidic bonds present in starch and include α-amylase, β-amylase, and γ-amylase.10 α-Amylase acts at random locations along the starch chain and breaks down long-chain carbohydrates to ultimately yield maltotriose and maltose (a disaccharide) from amylose, or maltose, glucose, and “limit dextrin” from amylopectin.11 β-Amylase, which acts from the non-reducing end, catalyzes the hydrolysis of the second α-1,4-glycosidic bond and cleaves off two glucose units (maltose) at a time. γ-Amylase, also called glucoamylase, cleaves α-1,6-glycosidic linkages, as well as the last α-1,4-glycosidic linkages at the non-reducing end of amylose and amylopectin, to yield glucose.
Production of Butanol from Corn
Published in Shelley Minteer, Alcoholic Fuels, 2016
Thaddeus C. Ezeji, Nasib Qureshi, Patrick Karcher, Hans P. Blaschek
Amylases are enzymes that act on starch, glycogen, and derived polysaccharides. They hydrolyze α-1, 4 or α-1, 6 glucosidic bonds between consecutive glucose units. α-Amylase (1,4-α-D-glucanohydrolase; EC 3.2.1.1) catalyzes the hydrolysis of α-1,4 glucosidic bonds in the interior of the substrate molecule (starch, glycogen and various oligosaccharides) and produces a mixture of glucose, maltose, maltotriose, maltotetraose, maltopentose, maltohexaose, and oligosaccharides in a ratio depending on the source of the enzyme (Ezeji, 2001). The β-amylase (1, 4-α-D-glucan maltohydrolase; EC 3.2.1.2) hydrolyzes α-1,4 glucosidic bonds in starch and oligosaccharides producing maltose units from the nonreducing terminal end of the substrate. Glucoamylase (1, 4-α-D-glucan glucohydrolase; EC 3.2.1.3) hydrolyzes both α-1, 4 and α-1, 6 glucosidic linkages from the nonreducing terminal end of the glucose units in the starch molecule. α-Glucosidase (α-D-glucoside glucohydrolase; EC 3.2.1.20) catalyzes, like glucoamylase, the hydrolysis of the terminal nonreducing α-1, 4-linked glucose units in the starch. The preferred substrates for α-glucosidases are maltose, maltotriose, maltotetraose, and short oligosaccharides. Furthermore, pullulanases (α-dextrin 6-glucanohydrolase; EC 3.2.1.41) are enzymes that cleave -1, 6 linkages in pullulan and release maltotriose, although pullulan itself may not be the natural substrate.
An amylopullulanase (ApuNP1) from Geobacillus thermoleovorans NP1: biochemical characterization and its potential industrial applications
Published in Preparative Biochemistry and Biotechnology, 2019
The products released after the hydrolysis of pullulan by the action of ApuNP1 were determined as glucose, maltose, maltotriose, and maltodextrin by TLC. As to soluble starch, the major hydrolysis products were maltose, maltotriose, and maltodextrin. According to the hydrolysis spots indicated in Figure 7, it could be concluded that the enzyme is a typical pullulanase type II (amylopullulanase) since it hydrolyzes α-(1,4)- and α-(1,6)-glycosidic bonds in the structure of starch and pullulan.[38] Lee at al.[43] found that PulSS4 amylopullulanase converted the starch to maltotetraose, maltotriose, maltose, and glucose, and pullulan to maltotriose. A previous study reported by Nisha and Satyanarayana[38] indicated that the enzyme from thermophilic Geobacillus thermoleovorans NP33 has an endo-acting α-amylase activity and hydrolyzes pullulan to maltotriose as the only end product.
Antidiabetic potential evaluation of aqueous extract of waste Syzygium cumini seed kernel’s by in vitro α-amylase and α-glucosidase inhibition
Published in Preparative Biochemistry & Biotechnology, 2021
Komal V. Mahindrakar, Virendra K. Rathod
Digestive enzymes α-amylase and α-glucosidase show catalytic actions in the body. α-Amylase partially hydrolyzes the starch into maltose, dextrin, and maltotriose. Afterward, these oligosaccharides and disaccharides break down into monosaccharides in the small intestine by α-glucosidase. The action of these enzymes increases the serum glucose level in DM-II patients. Hindering this hydrolysis by inhibiting the enzymes may control the blood glucose levels and decreases the disease-related complications in the DM-II patients.[41] Hence, SCKP aqueous extract is implicated in checking the α-amylase and α-glucosidase enzyme inhibitor's potential.
Valorization of waste Syzygium cumini seed kernels by three-phase partitioning extraction and evaluation of in vitro antioxidant and hypoglycemic potential
Published in Preparative Biochemistry & Biotechnology, 2021
Komal V. Mahindrakar, Virendra K. Rathod
The catalytic action (i.e. hydrolysis of polysaccharides to di- and mono-saccharides) of a digestive enzyme, α-amylase, increases the blood glucose availability. The enzyme α-amylase breakdowns the α-1, 4-glycosidic bonds of the starch and forms maltose, dextrin, and maltotriose. In this assay, the formation of these compounds was determined quantitatively by checking the reductive conversion of 3, 5-dinitro salicylic acid into 3-amino-5-nitro salicylic acid.[41] The strength of SCKP extracts to inhibit the α-amylase enzyme is expressed in terms of IC50 value. This value represents the concentration of extract needed to inhibit half of the α-amylase activity. A lower IC50 value denotes the higher potential for a particular activity. Inhibition was dependent on the concentration of extract used (Figure 11). Inhibition increased as the concentration of both positive control and extract increased from 10 to 100 μg/mL concentration, and IC50 values obtained are 23.95 and 9.33 µg/mL, respectively (Table 2). In literature, α-amylase inhibitory activity with the IC50 value of 24 mg/mL for Syzygium cumini seeds aqueous extract was obtained by mechanical shaking for 24 h.[42] Gajera et al. performed the soxhlet extraction of Syzygium cumini kernels for 72 h continuously with methanol as an extractant. The extract and standard drug acarbose were checked for α-amylase inhibition and IC50 values which were found as 8.3 µg/mL and 24.7 µg/mL, respectively.[43] Ethyl acetate extract of Syzygium cumini kernels and acarbose showed 43.2 and 124.5 µg/mL IC50 value for α-amylase inhibition, respectively.[44]