Of glucoamylase

SoKd substrate fermentation using agricultural wastes was considered to be used for the production of both enzymes in order to reduce the production costs. Production of glucoamylase from Aspergillus niger J8 was reported (1,3). This report concerned on the production of pectinases from Rhizopus sp. 26R in solid substrates composting of agricultural wastes, optimization of the conditions for pectinases production in solid substrates and the estimation of the production cost. 

FIGURE 6.16 AFM images of glucoamylase-amylose complexes and binding models. 

Morris, V. J., Gunning, A. P., Faulds, C. B., Williamson, G., and Svensson, B. (2005). AFM images of complexes between amylose and Aspergillus niger glucoamylase mutants, native, and mutant starch binding domains A model for the action of glucoamylase. Starch-Starke 57,1-7. 

Federici, F., Petruccioli, M., and Miller, M. W., Enhancement and Stabilization of the Production of Glucoamylase by Immobilized Cells ofAureobasidium pullulans in a Fluidized-Bed Reactor, Appl. Microbiol. Biotechnol., 33 407... 

S. Kitahata, C. F. Brewer, D. S. Genghof, T. Sawai, and E. J. Hehre, Scope and mechanism of carbohydrase action. Stereocomplementary hydrolytic and glu-cosyl-transferring actions of glucoamylase and glucodextranase with alpha- and beta-D-glucosyl fluoride, J. Biol. Chem., 256 (1981) 6017-6026. 

Abraham TE, Jamuna R, Bansilal CV, Ramakrishna SV (1991) Continuous synthesis of glucoamylase by immobilized fungal mycelium of Aspergillus niger. Starch-Starke 43 113-116... 

Christensen, T., B. Svensson, and B.W. Sigurskjold. 1999. Thermodynamics of reversible and irreversible unfolding and domain interactions of glucoamylase from Aspergillus niger studied by differential scanning and isothermal titration calorimetry. Biochemistry 38 6300-6310. 

Sigurskjold, B.W., C.R. Berland, and B. Svensson. 1994. Thermodynamics of inhibitor binding to the catalytic site of glucoamylase from Aspergillus niger determined by displacement titration calorimetry. Biochemistry 33 10191-10199. 

Several variations on these production methods also exist, such as the use of immobilized CGTase (2i, 22), continuous ultrafiltration 23) and the use of isoamylase to increase CD yield. Variations of purification methods include the addition of glucoamylase to degrade non-CD starch hydrolysates to simply separation and the use of various S3mthetic ion exchange resins in chromatographic separations 24-26) and acuity columns (27),... 

Roy, I. and Gupta, M.N., Hydrolysis of starch by a mixture of glucoamylase and pullulanase entrapped individually in calcium alginate beads, Enzyme Microbial Tech., 34 (2004) 26-32. 

M. R. Sierks and B. Svensson, Energetic and mechanistic studies of glucoamylase using molecular recognition of maltose OH groups coupled with site-directed mutagenesis, Biochemistry, 39 (2000) 8585-8592. 

Mannose is primarily found in mammalian N-linked glycoproteins as part of core structures containing the tri-Man core [a-D-Man-(1 3)-a-D-Man-(1 6)-Man]. However, in the glycoproteins of yeast and molds, mannose, primarily a-D-Man-(1 2)-a-D-Man and a-D-Man-(1 6)-a-D-Man, has been found a-linked to Ser or Thr. 244 Expression of glucoamylase G1 in Aspergillus niger 245 and human IGF-I (somatomedin C) in Saccharomyces cerevisiae 246 resulted in proteins glycosylated with mannose at Ser and Thr. 

Pavezzi, F. C., Gomes, E., da Silva, R. (2008). Production and characterization of glucoamylase from fungus Aspergillus awamori expressed in yeast Saccharomyces cerevisiae using different carbon sources. Braz. 

Ariff and Webb studied production of glucoamylase using freely suspended cells of Aspergillus awamori in batch and continuous fermentations. Glucoamylase yields based on glucose consumed were 900 and 1080 U/g for batch and continuous fermentations, respectively. The immobilization of viable cells was achieved by adsorption to cubes of reticulated polyurethane foam. In comp uison with freely suspended cell fermentations, neither batch nor continuous fermentations of immobilized cells improved glucoamylase production significantly in tenns of yield or productivity. 

Structural features met in some cellulases include an a,a barrel111 similar to that of glucoamylase (Fig. 2-29) and, in a cellobiohydrolase,101 a 5-nm-long tunnel into which the cellulose chains must enter. Ten well-defined subsites for glycosyl units are present in the tunnel.101 A feature associated with this tunnel is processive action, movement of the enzyme along the chain without dissociation,105 a phenomenon observed long ago for amylases (see Section 9) and often observed for enzymes acting on nucleic acids. 

Hyper Production System of Glucoamylase Under Melo Gene Promoter Control... 

Two forms of glucoamylase (often incorrectly called amyloglucosidase) have been observed in the culture supernatants of Aspergillus niger, A. awamori and... 

Figure 7.10 Schematic representation of the domain structure of glucoamylases Aspergillus niger glucoamylase-1, with starch-binding, linker and catalytic domains Aspergillus mger glucoarriylase-2, with only the catalytic domain Rhizopus nievus glucoamylase-l, with starch binding, linker and catalytic domains...

Three forms of glucoamylase occur in the culture supernatants of Rhizopus sp. They have molecular weights of 74000, 58000 and 61000, and have been designated GA-I, GA-II and GA-III.150 GA-I bound and hydrolyzed native starch granules, but GA-II and GA-III neither bound nor hydrolyzed native starch granules.151 The three glucoamy-lases had the same C-terminal end, but differed in their N-terminal ends.152 Two... 

Figure 7.11 Topological comparison ofthe (a/(3) —TIM barrel structure ofthe a-amylases (A) and the a/a-barrel structure of glucoamylase (B). a-Helices are represented as circles and (3-strands as squares. (From Aleshin et al. 147 reprinted by permission)...

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