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Produced by Recombinant Bacteria
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Glucoamylase (EC 3.2.1.3; α-1,4-d-glucan glucohydrolase) is an exotype enzyme that consecutively removes glucose from the nonreducing end of starch. In industry, the enzyme is used in combination with debranching enzyme to produce glucose from starch liquefied by α-amylase. Glucoamylase is produced by many microorganisms, such as Sac char omycopsis, Aspergillus, Pénicillium, Mucor, Rhizopus, and Clostridium species. Enzymes form Aspergillus and Rhizopus species are used mainly in industry. The nucleotide sequences of the glucoamylase genes of Saccharomyces diastaticus [30,31], Aspergillus awamori [32,33], S aechar omycopsis film ligera [34,35], and Aspergillus oryzae [36] have been determined. A comparison of the amino acid sequence of glucoamylases from several fungi and yeasts showed five highly conserved regions [34].
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.
Ion-Exchange Processes
Published in Juan A. Asenjo, Separation Processes in Biotechnology, 2020
The production of high-fructose corn syrup (HFCS) is a success story in biotechnology. It is manufactured using three mass-produced enzymes. First, a-amylase and glucoamylase are used to break down cornstarch to give glucose, and then glucose isomerase converts part of the glucose into fructose. The conversion to fructose is necessary to give the syrup a sweetness comparable to that of sucrose. However, to achieve an acceptable result, the fructose concentration must be raised to 55% from the 44% concentration that occurs at the iso-merization equilibrium.
An overview of simultaneous saccharification and fermentation of starchy and lignocellulosic biomass for bio-ethanol production
Published in Biofuels, 2019
Starch molecule is basically hydrolyzed by the action of amylolytic enzymes: α-amylase (for liquefaction) and glucoamylase (for saccharification).There are numerous bacteria and fungi which can produce α-amylases and glucoamylase. In bacterial culture, α-amylase is mostly produced by Bacillus spp. like Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus subtilis and Bacilus megaterium. Amylases are also produced by various fungus species like Aspergillus oryzae and Aspergillus niger. It has been reported that Aspergillus amylase produces more sugar than Bacillus amylase [24]. In a similar way, glucoamylase can be produced by bacterial Rhizopus species, Endomyces species and few Bacillus species. Fungal resources for the same are Aspergillus niger, Aspergillus oryzae, Aspergillus saitai and Aspergillus awamori. In the second stage of the process Saccharomyces cerevisiae can be effectively used as it is the most promising microorganism for ethanol production.
Development of a process model for simultaneous saccharification and fermentation (SSF) of algal starch to third-generation bioethanol
Published in Biofuels, 2020
Sukhendra Singh, Ipsita Chakravarty, Kapil Deo Pandey, Subir Kundu
Fermentation of algal starch was performed by SSF. In this process, first algal starch was hydrolyzed to glucose by crude amylase enzymes. The crude amylase mainly contains alpha-amylase and glucoamylase, which break the glycosidic bonds present in starch. After enzymatic hydrolysis, the S. cerevisiae strain was used for fermentation of reducing sugars.
Production of bioethanol from liquid waste from cassava dough during gari processing
Published in Biofuels, 2019
Francis Kotoka, Samuel Kofi Tulashie, Daniel Dodzi Setsoafia
Aspergillus niger had been reported to be very prolific in glucoamylase production [27], thermostable and abundantly available [28]. They can be found in industrial waste potatoes [27], soils [29], and contaminated foods. A piece of bread was moistened and kept at room temperature in the dark for four days to grow Aspergillus niger.