Glucose oxidase production

The control of glucose oxidase production is still not fully eluddated, nor is the role of gluconic add in cells. However, elevated levels of glucose oxidase are found in conditions of high glucose concentrations and above normal oxygen tension. 

High aeration rates are required to stimulate glucose oxidase production and activation. 

Another group of compounds called oxygen scavengers retard oxidation by reducing the available molecular oxygen. Products in this group are water soluble and include erythorbic acid [89-65-6] C HgO, and its salt sodium erythorbate [6381-77-7] C HgO Na, ascorbyl pahnitate [137-66-6] 22 38 7 ascorbic acid [50-81-7] C HgO, glucose oxidase [9001-37-0] and sulfites (23). 

Multienzyme Electrodes. Coupling the reactions of two or more immobilized enzymes increases the number of analytes that can be measured. An electro-inactive component can be converted by an enzyme to a substrate that is subsequentiy converted by a second enzyme to form a detectable end product (57). For example, a maltose [69-79-4] sensor uses the enzymes glucoamylase and glucose oxidase, which convert... 

Dried Whole Egg and Yolk. Dried plain whole egg and yolk products are either dried as is, or have the glucose removed to improve stabiHty and shelf life of the product. Glucose is removed before drying by use of glucose oxidase or by yeast fermentation (see Yeasts). Bacterial fermentation is not used because of off-flavor and off-odor development. 

The hydrogen peroxide produced in the glucose oxidase catalyzed reaction has an antibacterial action. If the presence of hydrogen peroxide is undesirable in the product, catalase is added to remove the peroxide. 

The pH has to be controlled - the acid which is produced has to be neutralised maintaining a pH in excess of 6.0. Below pH 3.0 the glucose oxidase is inactivated and in fungal systems low pH encourages citric add production. 

Production of D-gluconolactone from glucose in several fungi is a one-step process catalysed by glucose oxidase. 

Several studies have demonstrated the production of mucosal damage and/or increased mucosal permeability by hydrogen peroxide, the hydroxyl radical, or by installation of xanthine or glucose oxidase (Gregaard et al., 1982 Parks et al., 1984 Joubert-Smith et al., 1991 Kohen etal., 1992). 

Depending on the immobilization procedure the enzyme microenvironment can also be modified significantly and the biocatalyst properties such as selectivity, pH and temperature dependence may be altered for the better or the worse. Mass-transfer limitations should also be accounted for particularly when the increase in the local concentration of the reaction product can be harmful to the enzyme activity. For instance H2O2, the reaction product of the enzyme glucose oxidase, is able to deactivate it. Operationally, this problem can be overcome sometimes by co-immobilizing a second enzyme able to decompose such product (e.g. catalase to destroy H202). 

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