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Immobilization of urease on dialdehyde porous starch
Author(s) -
Luo Zhigang,
Fu Xiong
Publication year - 2010
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.201000067
Subject(s) - urease , chemistry , periodate , hydrolysis , immobilized enzyme , chromatography , adsorption , nuclear chemistry , enzyme , organic chemistry
Abstract Dialdehyde porous starch (DPS) was prepared by enzymatic hydrolysis and periodate oxidation. Urease was immobilized on DPS by several techniques including physical adsorption and covalent bonding. Optimum urease immobilization conditions for maximum enzyme activity were shown as following: immobilization pH 6.0, processing time of immobilization 25 h, immobilization temperature 25°C, aldehydic groups content 79.6% and ratio of supporter to urease 1:2 (w/v in g/mL). Temperature optimum of the free and immobilized urease were 60 and 70°C, respectively. The temperature curve of the immoblized urease was wider than that registered for the free urease. After being stored at ambient temperature for 42 days, the immobilized urease retained almost all of the original activity. DPS was found capable of holding the urease enzyme during a repeated cyclic test for ten times. An increase of the K m value for the immobilized urease was found. The foregoing data indicated that DPS is a fine supporter for urease and provided a basis for biosensor or bioreactor development with reduced costs and improved shelf life.