Immobilization Of Glucoamylase Research Articles

Immobilization of glucoamylase on DEAE-cellulose activated with chloride compounds

Partially purified glucoamylase (1,4-α- d-glucan glucohydrolase, EC 3.2.1.3) from Aspergillus niger NRRL 330 has been immobilized on DEAE-cellulose activated with cyanuric chloride in 0.2 m acetate buffer, pH 4.2. In the matrix-bound glucoamylase, enzyme yield was 20 mg g −1 of support, corresponding to 40 200 units g −1 of DEAE support. Binding of the enzyme narrows the pH optimum from 3.8–5.2 to 3.6. Thermal stability of the bound glucoamylase enzyme was decreased although it showed a higher temperature optimum (70°C) than the free form (55°C). The rate of reaction of glucoamylase was also changed after immobilization. V max values for free and bound enzyme were 36.6 and 22.6 μmol d-glucose ml −1 min −1 and corresponding K m values were 3.73 and 4.8 g l −1 respectively. Free and immobilized enzyme when used in the saccharification process gave 84 and 56% conversion of starch to d-glucose, respectively. The bound enzyme was quite stable and in the batch process it was able to operate for about five cycles without any loss of activity.

Immobilization of glucoamylase on naphthyl cotton cloth

Aspergillusniger glucoamylase was adsorbed to β-naphthyl cotton cloth by hydrophobic interaction. The adsorbed enzyme was cross-linked with glutaraldehyde. The immobilized glucoamylase exhibited greater pH dependence though the optimal pH did not change. The immobilized glucoamylase in a packed bed column completely hydrolysed 5% soluble starch at a specific velocity of about 4. Used naphthyl cloth could be regenerated by heating in 2 N NaOH at 100°C for 1 hour.

Keratin and polyamide-coated inorganic matrices as supports for glucoamylase immobilization

Previously solubilized feather keratin and polyamide were used for coating sand, glass beads and silica gel. These new seven supports were employed for comparative studies on pure glucoamylase / EC 3.2.1.3 / immobilization. The immobilization yield of glucoamylase on keratin and polyamide coated supports was comparable with conventional matrices used earlier. The highest activity per 1 g of support was shown by the enzyme bound to polyamide-coated CPG, and the bests operational stability by the enzyme immobilized on polyamide-coated CPG with keratin subsequently deposited on it.

Immobilization of Glucoamylase on Silanized Aluminium Oxide

AbstractThe possibility of immobilization of glucoamylase (GA) on silanized Al2O3 was examined using adsorption and covalent bonding via glutaric aldehyde. Both methods yield active unsoluble enzymes, which however gradually lose their catalitic activity in cyclic operation. Various agents aiming to improve the stability of immobilized GA were tested. It has beer found that the enzyme bound covalently to the carrier retains its activity to the higher degree while kept in the substrate solution.

Immobilization of Glucoamylase on Activated Aluminiumoxide

AbstractThe adsorption capacity of glucoamylase on unactivated, γ‐irradiation activated and transition metal alumina as well as the catalytic activity and stability of immobilized enzyme were studied.

Immobilization of glucoamylase and glucose oxidase in activated carbon: Effects of particle size and immobilization conditions on enzyme activity and effectiveness

Glucoamylase and glucose oxidase have been immobilized on carbodiimide-treated activated carbon particles of various sizes. Loading data indicate nonuniform distribution of immobilized enzyme within the porous support particles. Catalysts with different enzyme loading and overall activities have been prepared by varying enzyme concentration in the immobilizing solution. Analysis of these results by a new method based entirely upon experimentally observable catalyst properties indicates that intrinsic catalytic activity is reduced by immobilization of both enzymes. Immobilized glucoamylase intrinsic activity decreases with increasing enzyme loading, and similar behavior is suggested by immobilized glucose oxidase data analysis. The overall activity data interpretation method should prove useful in other immobilized enzyme characterization research, especially in situations where the intraparticle distribution of immobilized enzyme is nonuniform and unknown.

Pretreatment of starch raw materials and their enzymatic hydrolysis by immobilized glucoamylase

The pretreatment of starch raw materials such as sweet potato, potato and cassava has been carried out using various types of crusher, viz juice mixer, homogenizer and high-speed planetary mill. The effect of pretreatment of the materials on their enzymatic hydrolysis was studied. High-speed planetary mill treatment was the most effective and comparable with heat treatment (pasting). Various crushing times were used to examine the effect of crushing by mill treatment on the enzymatic hydrolysis. In the enzymatic hydrolysis of cassava, the use of both cellulase [1,4-(1,3; 1,4)-β- d-glucan 4-glucanohydrolase, EC 3.2.1.4] and glucoamylase [1,4-α- d-glucan glucohydrolase, EC 3.2.1.3] enhanced the d-glucose yield. The immobilization of glucoamylase was studied by radiation polymerization of hydrophilic monomers at low temperature, and it was found that enzymatic activity of the immobilized glucoamylase particles varied with monomer concentration and particle size. Starchy raw materials pretreated with the mill can be efficiently hydrolysed by immobilized glucoamylase.

Immobilization of alpha-amylase, glucoamylase and glucose isomerase on CNBr activated Sepharose-6MB

Two enzymes (Glucoamylase from Rhizopus Sp. and Glucose isomerase from Streptomyces fradiae) or three enzymes (the above two and α-amylase from Bacillus subtilis) were coupled to CNBr activated Sepharose-6MB. Some of the parameters such as the pH and temperature activity relationships of the immobilized enzyme systems are described. A 5% soluble starch solution was converted by the enzyme system into a mixture of glucose and fructose within 6 hr at 60° C.

Immobilization of mold and bacterial amylases on silica carriers

The immobilization of alpha-amylase and glucoamylase was investigated by several coupling methods on silica carriers, different types of Silokhroms, and silica gels. The most active immobilized mold and bacterial alpha-amylases and mold glucoamylase were obtained with titanium salts. These activities were twice the value of that obtained by glutaraldehyde or azo coupling. The half-lives of A. oryzae alpha-amylase, B. subtilis alpha-amylase, and A. niger glucoamylase, immobilized to silica carriers at 45 degrees C and under continuous operation at a high concentration of substrate, were 14, 35, and 65 days, respectively.

Immobilization of glucoamylase from Aspergillus niger on poly(ethylenimine)-coated non-porous glass beads

Glucoamylase (1,4-α- d-glucan glucohydrolase, EC 3.2.1.3) from A. niger was immobilized on cationic nonporous glass beads (13–44 μm) by electrostatic adsorption followed by rosslinking with glutaraldehyde. Over 80% of the enzyme's total soluble activity was expressed upon immobilization. d-Glucose production from maltodextrins was virtually complete, suggesting that the lack of pores can eliminate the problem of product reversion. Immobilized glucoamylase showed decreased stability upon heating, compared with the soluble enzyme .

Immobilization of glucoamylase on porous silicas

The influence of the pore structure of silica carriers (macroporous silica gels, silochromes and porous glasses) on the catalytic activity of immobilized glucoamylase (exo 1,4-α- d-glucosidase, 1,4-α- d-glucan glucohydrolase EC 3.2.1.3) has been studied. The dependence of the immobilized glucoamylase activity, in units g −1, on the carrier pore diameter was found to pass through a maximum within a range 70–100 nm. Macroporous silica gels can be used with success as carriers for glucoamylase immobilization instead of porous glasses and silochromes.

Immobilization of glucoamylase on polymer surface by radiation-induced polymerization of glass-forming monomers at low temperatures

Glucoamylase was immobilized in hydrophilic porous poly(2-hydroxyethyl methacrylate) (PHEMA) and hydrophobic microsphere poly(diethylene glycol dimethacrylate) (PDGDA) by radiation-induced polymerization at low temperatures, in the presence of acetate buffer solution. The distribution on the matrix of immobilized glucoamylase was investigated using fluoresce in isothiocyanate (FITC)-conjugated glucoamylase and the fluorescence microscope. It was found that in the porous PHEMA system, the FITC-conjugated glucoamylase is present mainly on the interface between polymer membrane and pore structure and partly in the polymer, while in the microsphere PDGDA system the immobilized glucoamylase is present merely on the surface of the polymer microsphere.

Immobilization of glucoamylase on gelatin by transition-metal chelation

The potential applicability of glutaraldehyde-crosslinked-gelatin particles for the immobilization of enzymes by encapsulation has been extended by addition of surface-bound enzyme, leading ultimately to a method for the preparation of dual immobilized enzyme conjugates. Attachment of enzyme to the surface of the capsules was achieved by a transition-metal chelation process in which the incoming enzyme becomes a ligand. Glucoamylase was so immobilized, using titanium-urea, -acrylamide, -citric acid, and -lactose complexes or titanium (IV) chloride as means of introducing the titanium chelating centre. The retentions of enzyme activity for both the surface-bound and pre-encapsulated enzymes were functions of the chelating complex chosen. Differences were observed between the action patterns of the two forms of immobilized enzyme. These action patterns and the production of reversion products are discussed in the light of application of gelatin-immobilized glucoamylase to the production of high-DE glucose syrups.

Studies on the Combined Action of Amylases and Glucose Isomerase on Starch and Its Hydrolysates Part II. Immobilization of Glucoamylase

AbstractAmberlite IR‐45 resin was used for immobilization of glucoamylase and the factors affecting the binding power of enzyme to resin, pH, buffer concentration and methods used for immobilization were studied and discussed. Also the factors affecting the reaction velocity of immobilized enzyme were in vestigated. The immobilized enzyme has a higher Km value (0.072) and narrow range of optimum temperature (65–70°C) than free enzyme. Optimum pH for immobilized glucoamylase was 5.5–6.5 while it was 4.5 for free enzyme.

Haloacetyl derivatives of styrene-divinylbenzene copolymers as carriers for the immobilization of enzymes

Styrene-divinylbenzene copolymers with various structures have been used as the basis for synthesizing compounds with mobile halogen atoms: these are the copolymers' brom- and iodoacetyl derivatives which have been used as polymeric carriers for the immobilization of glucoamylase and pepsin. The effect of the copolymers' macromolecular structure and the halogen content on the process of immobilizing glucoamylase and pepsin has been studied. It has been shown that the iodoacetyl derivatives of the styrene-divinylbenzene copolymers with a macro-porous structure and a high iodine content are the most suitable for immobilizing these enzymes.

An investigation of the properties of glucoamylase immobilized on glass beads involving 5-diazosalicylic acid bonded to a titanium (IV) oxide film

Optimum conditions have been determined for the immobilization of glucoamylase on glass involving diazotized 5-aminosalicylic acid bonded to a deposited imperfectly crystallized film of TiO 2. The changes in the kinetic and thermodynamic characteristics of the enzyme on immobilization have been determined. There are significant differences in the behaviour of the immobilized enzyme towards its substrates, maltose and starch. The apparent K m for starch increased on immobilization whereas that for maltose decreased. The pH optimum for the immobilized preparation showed a shift to acid pH relative to that of the free enzyme.

Immobilization of enzymes on activated carbon: Selection and preparation of the carbon support

Based upon its superior catalytic activity for H2O2 decomposition, a bituminous coal-based activated carbon was selected for investigations of pretreatment and enzyme immobilization methods. Pretreatments considered include acid washing, exposure to strong oxidizing agents, contact with concentrated peroxide solutions, nitration and amination, isothiocyanate derivatization, silanization, and stearic acid coating. Effects of these pretreatments on morphology and trace-metal content of the carbon pellets have been studied using scanning electron microscopy and dispersive analysis of x rays. Immobilization of glucoamylase by adsorption, glutaraldehyde crosslinking, and covalent attachment to carbon activated by water-soluble diimide or diazotization have been examined. These different enzyme-carbon catalysts have been characterized by their enzyme loading, enzyme activity, catalytic activity for H2O2 decomposition, or combinations of these measures of performance.

A heat transfer study on packed bed reactors of immobilized glucoamylase

AbstractEnzymes are generally sensitive to temperature changes. Porous glass particles used for glucoamylase immobilization are poor thermal conductors and a non‐uniform temperature distribution can conceivably develop in a packed bed reactor of immobilized glucoamylase on porous beads. This study was made to determine experimentally the temperature and concentration profiles in an immobilized glucoamylase column. This work provides a procedure for examining possible heat effects on reactor column performance in enzyme applications.