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Biocatalytic Performance of pH‐Sensitive Magnetic Nanoparticles Derived from Layer‐by‐Layer Ionic Self‐Assembly of Chitosan with Glucoamylase
Author(s) -
Wang Jianzhi,
Zhao Guanghui,
Li Yanfeng,
Peng Xiaomeng,
Li Yantao
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201300850
Subject(s) - chitosan , catalysis , zeta potential , chemistry , ionic strength , magnetic nanoparticles , nanoparticle , chemical engineering , ionic bonding , aldehyde , reusability , layer by layer , nuclear chemistry , ion , layer (electronics) , nanotechnology , materials science , organic chemistry , aqueous solution , engineering , software , computer science , programming language
Based on the characteristics of polycations of chitosan and glucoamylase, which are oppositely charged, they were successfully alternatingly deposited onto the surface of aldehyde‐modified Fe 3 O 4 nanoparticles by using a layer‐by‐layer ion exchange method to form magnetic carriers to construct multilayer films (designated as Fe 3 O 4 @(CS/GA) n ). The (CS/GA) n film systems were endowed with the pH‐dependent properties of chitosan as well as the catalytic activity of glucoamylase. The changes in weight loss and surface chemistry, morphology, and magnetic sensitivity were monitored and verified by UV/Vis spectroscopy, zeta potential, TEM, and a vibrating sample magnetometer. Subsequently, the influence of the number of bilayers, storage stability, pH, temperature, and reusability of Fe 3 O 4 @(CS/GA) 5 biocatalysts on catalytic activity were investigated. The results from characterization and determination remarkably indicate that Fe 3 O 4 @(CS/GA) 5 presents excellent catalytic activity , storage stability, pH stability, and reusability in comparison with free enzyme. Fe 3 O 4 @(CS/GA) 5 retained >60 % of its initial activity at 65 °C over 6 h; the optimum temperature and pH also increased to the ranges of 45–65 °C and 2.5–3.5, respectively, and only 27 % activity was lost after 10 cycles. This new strategy simplifies the reaction protocol and improves encapsulation efficiency and catalytic activity for new potential applications in biotechnology.