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Production of a new thermostable neutral α‐galactosidase from a strain of Bacillus stearothermophilus
Author(s) -
Delente J.,
Johnson J. H.,
Kuo M. J.,
O'Connor R. J.,
Weeks L. E.
Publication year - 1974
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.260160907
Subject(s) - catabolite repression , chemistry , autolysis (biology) , fermentation , chromatography , biochemistry , sephadex , enzyme , yeast , mutant , gene
An intracellular, thermostable, neutral α‐galactosidase (α‐ D ‐galactoside galactohydrolase EC 3.2.1.32) was produced in pilot plant quantities from a strain of Bacillus stearothermophilus . The organism was cultured at 50°C in a soluble neutral medium containing water extract of soybean meal (3%) and 0.5% yeast extract. The enzyme biosynthesis was inducible and sensitive to catabolite repression. After autolysis of the cells, the α‐galactosidase was selectively and quantitatively complexed from clarified beer directly onto DEAE Sephadex; and enzyme‐rich fractions were batchwise eluted with an increasing gradient of NaCl solutions. The eluates were given two consecutive isopropyl alcohol precipitations, and the aqueous solutions of the second precipitate were dialyzed and lyophilized. Final product activity recovery was 72% based on the crude fermentation beer. Best specific activity was 5.2 u/mg protein. Further laboratory purification (DEAE Sephadex and Bio‐Gel P200) yielded a product with 14.2 u/mg protein.