Production of a new thermostable neutral α‐galactosidase from a strain of Bacillus stearothermophilus

Abstract

An intracellular, thermostable, neutral a-galactosidase (a-D-galactoside galactohydrolase E C 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 (397,) and O.5y0 yeast extract. The enzyme biosynthesis was inducible and sensitive to catabolite repression. After autolysis of the cells, the a-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 72Y0 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.

α‐Galactosidase from the yeast Torulaspora delbrueckii IFO 1255

“…a-Galactosidase is widely distributed in many micro-organisms and has been purified from fungi (Adya and Elbein 1977;Zapater et al 1990;Dey et al 1993), yeasts (Lazo et al 1977 ;Church and Meyer 1980 ;Cavazzoni et al 1987 ;Hashimoto et al 1993) and bacteria (Delente et al 1974;Garro et al 1993Garro et al , 1994. These enzymes are used for removing raffinose and stachyose from soy milk and soy whey (Cruz et a1.…”

Cloning of the Gene Encoding a Novel Thermostable α-Galactosidase from Thermus brockianus ITI360

“…Thermophilic bacteria are known to be a source of thermostable hydrolytic enzymes, including ␣-galactosidases. Several ␣-galactosidases from thermophilic bacilli have already been studied regarding their potential as hydrolyzing enzymes for different substrates (13,16,17,30,51). Furthermore, ␣-galactosidases from the hyperthermophilic bacteria Thermotoga neapolitana and Thermotoga maritima were recently cloned and characterized (31,35).…”

Thermostable α-galactosidase fromBacillus stearothermophilusNUB3621: cloning, sequencing and characterization

“…Many α‐galactosidases of eubacterial and eukaryotic sources including enzymes from thermophilic bacilli have been studied extensively regarding their biochemical and physical properties [6,10–12]. Although many α‐galactosidase genes have been cloned and sequenced, only few are of thermophilic sources and still no primary structure of Bacillus stearothermophilus α‐galactosidase has been published.…”