ISSN:
0006-3592
Keywords:
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A derivative of crosslinked Sepharose, p-(N-acetyl-L-tyrosine azo) benzamidoethyl-CL-Sepharose 4B, was synthesized and used for the selective immobilization of thermostable lactase from Aspergillus oryzae.Preparations of soluble and immobilized lactase were evaluated under initial velocity conditions in a batch process. Immobilization had no significant effect on the pH optimum at 50°C or kinetic parameters at pH 4.5 or pH 6.5 and 50°C. At pH 4.5, the soluble enzyme possessed maximum activity at 60°C and the immobilized at 55°C; at pH 6.5 both showed maximum activity at 55°C. The activation energy, entropy, and enthalpy decreased significantly with immobilization at pH 4.5 but not at pH 6.5. When the immobilized enzyme was placed in a packed-bed reactor, the effect of temperature on activity was altered as reflected by a marked decrease in the thermodynamic parameters of activation at both pH levels. Upon immobilization there was also a dramatic increase in the apparent thermal stability of the lactase, and the mean half-life at 50°C was increased from 7.2 to 13 days at pH 4.5 and from 3.8 to 16 days at pH 6.5.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260240207
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