Immobilization on chitosan of a thermophilic trehalose synthase from Thermus thermophilus HJ6.
A thermostable trehalose synthase (TtTSase) from Thermus thermophilus HJ6 was immobilized on chitosan activated with glutaraldehyde. The yield of immobilization was evaluated as 39.68%. The optimum pH of the immobilized enzyme was similar to that of the free enzyme. However, the optimal temperature ranges were shifted by about 4 degrees C owing to better thermal stability after immobilization. The half-life of heat inactivation for free and immobilized enzymes was 5.7 and 6.3 days at 70 degrees C, respectively, thus showing a lager thermostability of the immobilized enzyme. When tested in batch reaction, the immobilized enzyme retained its relative activity of 53% after 30 reuses of reaction within 12 days, and still retained 82% of its initial activity even after 150 days at 4 degrees C. A packed-bed bioreactor with immobilized enzyme showed a maximum yield of 56% trehalose from 100 mM maltose in a continuous recycling system (bed volume: 10 ml) under conditions of pH 7.0 and 70 degrees C.
Kim
Hyun-Jung
HJ
Department of Biomaterial Control, Dong-Eui University, Busan 614-714, Korea.
Kim
Ae-Ran
AR
Jeon
Sung-Jong
SJ
D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods*; D048271:Chitosan / Q000737:chemistry*; D004795:Enzyme Stability / Q000502:physiology; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry* / Q000378:metabolism; D005976:Glutaral / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D016963:Thermus thermophilus / Q000201:enzymology*
D004800:Enzymes, Immobilized; D048271:Chitosan; D005964:Glucosyltransferases; C099692:trehalose synthase; D005976:Glutaral