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Properties of soluble and immobilized Aspergillus niger β‐xylosidase
Author(s) -
Oguntimein Gbekeloluwa B.,
Reilly Peter J.
Publication year - 1980
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260220604
Subject(s) - aspergillus niger , glutaraldehyde , chemistry , enzyme , immobilized enzyme , nuclear chemistry , chromatography , organic chemistry , biochemistry
Aspergillus niger β‐xylosidase was characterized when in soluble form and when immobilized to alkylamine porous silica with glutaraldehyde and to alumina with titanium tetrachloride. Energies of activation averaged 13.4 KcaL/mol for the soluble enzyme, 9.0 Kcal/mol when immobilized to alumina, and 8.0 Kcal/mol when bound to silica. The highest activity of all forms of β‐xylosidase was found near pH 3. The soluble enzyme was highly stable at pH 4, where lowest rates of decay occurred, and temperature of 65°C and below. The decay rates of alumina‐bound β‐xylosidase and pH 4 and equivalent temperatures were approximately 10 times as high. Michaells constants were 0.200 and 0.262m M for o ‐nitrophenyl‐β‐ D ‐xylopyranoside with soluble and alumina‐bound β‐xylosidase, respectively.