Journal ArticleDOI
Kinetics of condensation of glucose into maltose and isomaltose in hydrolysis of starch by glucoamylase.
TLDR
A simple kinetic model for the hydrolysis of starch by glucoamylase from Aspergillus niger and Rhizopus niveus was proposed, and it was found to have practical use.Abstract:
Kinetics of the condensation of glucose into maltose and isomaltose in the hydrolysis of starch by two types of glucoamylase (from Aspergillus niger and Rhizopus niveus) was studied both experimentally and theoretically. A kinetic model for the hydrolysis of starch by glucoamylase from A. niger was proposed. In this model the reversible hydrolysis of maltose and isomaltose and the kinetic parameters change were taken into consideration. Calculated values agreed approximately with the experimental results, and this simple kinetic model was found to have practical use. The rate of condensation of glucose into isomaltose by enzyme from A. niger was about three times larger than that by enzyme from R. niveus. At a higher initial concentration of starch a large amount of isomaltose was reversed, and the glucose yield was reduced significantly after very long reaction times.read more
Citations
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Journal ArticleDOI
Pullulanase: Role in Starch Hydrolysis and Potential Industrial Applications
TL;DR: Each category of pullulanase, properties of pullulinase, merits of applying pullul anase during starch bioprocessing, current genetic engineering works related to pullulAnase genes, and possible industrial applications of pullULanase are reviewed.
Journal ArticleDOI
Enzymatic conversions of starch.
Piotr Tomasik,Derek Horton +1 more
TL;DR: Methods for the enzymatic conversion of starch, involving hydrolases and nonhydrolyzing enzymes, as well as the role of microorganisms producing such enzymes, are surveyed, covering the period from the early 19th century up to 2009.
Journal ArticleDOI
Modelling of potato starch saccharification by an Aspergillus niger glucoamylase
Milan Polakovič,Jolanta Bryjak +1 more
TL;DR: The kinetics of hydrolysis of a soluble potato starch catalysed by free glucoamylase was investigated in a batch reactor using a six-parameter model based on a kinetic equation, which contained product and substrate inhibition terms.
Journal ArticleDOI
Subsite mapping of Aspergillus niger glucoamylases I and II with malto‐ and isomaltooligosaccharides
TL;DR: Glucoamylase, industrially derived from Aspergillus niger, was chromatographically separated into forms I and II and purified to near homogeneity, proved to be free of D‐glucosyltransferase by electrophoretic and differential inhibition tests.
Journal ArticleDOI
Kinetics, equilibria, and modeling of the formation of oligosaccharides from D‐glucose with Aspergillus niger glucoamylases I and II
TL;DR: Near‐homogeneous forms of glucoamylases I and II, previously purified from an industrial Aspergillus niger preparation, were incubated with D‐glucose at a number of temperatures and pH values and agreement of simulated and actual oligosaccharide formation data through the course of the reaction was excellent except at very high solid concentrations.
References
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Journal ArticleDOI
Configurational specificity: Unappreciated key to understanding enzymic reversions and de novo glycosidic bond synthesis: I. Reversal of hydrolysis by α-, β- and glucoamylases with donors of correct anomeric form☆
TL;DR: Reversions represent the only class of carbohydrase-catalyzed reactions not previously shown to follow this mechanism, and their addition demonstrates the complete generality of the glycosyl-hydrogen interchange model proposed as the paradigm for the action of the carbohydrases.
Journal ArticleDOI
A kinetic expression for hydrolysis of soluble starch by glucoamylase.
TL;DR: A simple practical kinetic expression, which consists of a modified Michaelis–Menten form with product inhibition, is presented for the hydrolysis of soluble starch, assuming that the values of kinetic parameters Vm and Km vary linearly from the values for starch toward those for maltose.
Journal ArticleDOI
Effect of pore diffusion limitation on dextrin hydrolysis by immobilized glucoamylase.
TL;DR: Data reported here and previously indicate that when dextrin is hydrolyzed in the presence of immobilized glucoamylase, use of a larger average molecular weight substrate leads to lower overall rates of hydrolysis, while the maltose concentration during the bulk of the reaction and the maximum glucose concentration are lower than when the soluble form of the enzyme is employed under the same conditions.
Journal ArticleDOI
A kinetic model for the hydrolysis and synthesis of maltose, isomaltose, and maltotriose by glucoamylase.
TL;DR: Under a wide range of initial conditions, experimental results are adequately described by a new kinetic model with simple first‐ and second‐order, or Michaelian‐type, rate expressions for the reversible hydrolysis of maltotriose, maltose, and isomaltose.
Journal ArticleDOI
Kinetics of formation of maltose and isomaltose through condensation of glucose by glucoamylase.
TL;DR: A kinetic model was devised for the hydrolysis and synthesis of maltose and isomaltose by two glucoamylases from Rhizopus niveus and Aspergillus niger, and the validity of the model was verified experimentally at 313 K and pH 5.0.