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Immobilization of glucose oxidase in alginate-chitosan microcapsules.

Wang X, Zhu KX, Zhou HM - Int J Mol Sci (2011)

Bottom Line: The interaction between alginate and chitosan was confirmed by infrared spectroscopy (IR).The resultant CACM in wet state, whose morphology was investigated by scanning electron microscopy (SEM), was spherical with a mean diameter of about 26 μm.The results reveal the great potential of CACM-GOX as a flour improver.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu, China; E-Mails: hawangxia@yahoo.cn (X.W.); kxzhu@jiangnan.edu.cn (K.-X.Z.).

ABSTRACT
In order to improve its stability and catalytic rate in flour, the immobilization of glucose oxidase (GOX) was investigated in this work. The enzyme was encapsulated in calcium alginate-chitosan microspheres (CACM) using an emulsification-internal gelation-GOX adsorption-chitosan coating method. The interaction between alginate and chitosan was confirmed by infrared spectroscopy (IR). The resultant CACM in wet state, whose morphology was investigated by scanning electron microscopy (SEM), was spherical with a mean diameter of about 26 μm. The GOX load, encapsulation efficiency and activity of the CACM-GOX were influenced by concentration of chitosan, encapsulation time and encapsulation pH. The highest total enzymatic activity and encapsulation efficiency was achieved when the pH of the adsorption medium was near the isoelectric point (pI) of GOX, approximately pH 4.0. In addition, the molecular weight of chitosan also evidently influenced the encapsulation efficiency. Storage stabilities of GOX samples were investigated continuously over two months and the retained activity of CACM-GOX was 70.4%, markedly higher than the 7.5% of free enzyme. The results reveal the great potential of CACM-GOX as a flour improver.

Show MeSH
Effect of encapsulation time on specific GOX activity. The specific activity of CACM-GOX is the ratio of total activity of CACM-GOX to encapsulation efficiency.
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f7-ijms-12-03042: Effect of encapsulation time on specific GOX activity. The specific activity of CACM-GOX is the ratio of total activity of CACM-GOX to encapsulation efficiency.

Mentions: The specific CACM-GOX activity, to measure the catalytic rate of the immobilized enzyme, was taken as the ratio of total CACM-GOX activity to the encapsulation efficiency. It was maximum in the presence of 0.5% chitosan, the next was 1.0% followed by 2% (Figure 7), which may have been induced by the low rate of passing through for the substrate and product of the enzyme because of the thicker coating and more compact lattice structure of the semi-permeable membrane. It also possibly blocked the binding site of load GOX with glucose, leading to a decrease in the apparent activity of loaded enzyme. Moreover, the aggregation of microcapsules in 2% chitosan affected the measurement of enzymatic activity, which explained the great deviation in enzymatic activity.


Immobilization of glucose oxidase in alginate-chitosan microcapsules.

Wang X, Zhu KX, Zhou HM - Int J Mol Sci (2011)

Effect of encapsulation time on specific GOX activity. The specific activity of CACM-GOX is the ratio of total activity of CACM-GOX to encapsulation efficiency.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3116174&req=5

f7-ijms-12-03042: Effect of encapsulation time on specific GOX activity. The specific activity of CACM-GOX is the ratio of total activity of CACM-GOX to encapsulation efficiency.
Mentions: The specific CACM-GOX activity, to measure the catalytic rate of the immobilized enzyme, was taken as the ratio of total CACM-GOX activity to the encapsulation efficiency. It was maximum in the presence of 0.5% chitosan, the next was 1.0% followed by 2% (Figure 7), which may have been induced by the low rate of passing through for the substrate and product of the enzyme because of the thicker coating and more compact lattice structure of the semi-permeable membrane. It also possibly blocked the binding site of load GOX with glucose, leading to a decrease in the apparent activity of loaded enzyme. Moreover, the aggregation of microcapsules in 2% chitosan affected the measurement of enzymatic activity, which explained the great deviation in enzymatic activity.

Bottom Line: The interaction between alginate and chitosan was confirmed by infrared spectroscopy (IR).The resultant CACM in wet state, whose morphology was investigated by scanning electron microscopy (SEM), was spherical with a mean diameter of about 26 μm.The results reveal the great potential of CACM-GOX as a flour improver.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu, China; E-Mails: hawangxia@yahoo.cn (X.W.); kxzhu@jiangnan.edu.cn (K.-X.Z.).

ABSTRACT
In order to improve its stability and catalytic rate in flour, the immobilization of glucose oxidase (GOX) was investigated in this work. The enzyme was encapsulated in calcium alginate-chitosan microspheres (CACM) using an emulsification-internal gelation-GOX adsorption-chitosan coating method. The interaction between alginate and chitosan was confirmed by infrared spectroscopy (IR). The resultant CACM in wet state, whose morphology was investigated by scanning electron microscopy (SEM), was spherical with a mean diameter of about 26 μm. The GOX load, encapsulation efficiency and activity of the CACM-GOX were influenced by concentration of chitosan, encapsulation time and encapsulation pH. The highest total enzymatic activity and encapsulation efficiency was achieved when the pH of the adsorption medium was near the isoelectric point (pI) of GOX, approximately pH 4.0. In addition, the molecular weight of chitosan also evidently influenced the encapsulation efficiency. Storage stabilities of GOX samples were investigated continuously over two months and the retained activity of CACM-GOX was 70.4%, markedly higher than the 7.5% of free enzyme. The results reveal the great potential of CACM-GOX as a flour improver.

Show MeSH