Thermostable alkaline cellulase from an alkaliphilic isolate, Bacillus sp. KSM-S237.
Thermostable alkaline cellulase (endo-1,4-beta-glucanase, EC 3.2.1.4) activity was detected in the culture medium of a strictly alkaliphilic strain of Bacillus, designated KSM-S237. This novel enzyme was purified to homogeneity by a two-step column-chromatographic procedure with high yield. The N-terminal amino acid sequence of the purified enzyme was Glu-Gly-Asn-Thr-Arg-Glu-Asp-Asn-Phe-Lys-His-Leu-Leu-Gly-Asn-Asp-Asn-Val- Lys-Arg. The enzyme had a molecular mass of approximately 86 kDa and an isoelectric point of pH 3.8. The enzyme had a pH optimum of 8.6-9.0 and displayed maximum activity at 45 degrees C. The alkaline enzyme was stable up to 50 degrees C and more than 30% of the original activity was detectable after heating at 100 degrees C and at pH 9.0 for 10 min. The enzyme hydrolyzed carboxymethylcellulose, lichenan (beta-1,3;1,4-linkage), and p-nitrophenyl derivatives of cellotriose and cellotetraose. Crystalline forms of cellulose (Avicel and filter paper), H3PO4-swollen cellulose, NaOH-swollen cellulose, curdlan (beta-1,3-linkage), laminarin (beta-1,3;1,6-linkage), and xylan were barely hydrolyzed at all.
Hakamada
Y
Y
Tochigi Research Laboratories of Kao Corporation, Haga, Japan. 300475@kastanet.kao.co.jp
Koike
K
K
Yoshimatsu
T
T
Mori
H
H
Kobayashi
T
T
Ito
S
S
D000595:Amino Acid Sequence; D001407:Bacillus / Q000145:classification / Q000201:enzymology*; D002480:Cellulase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007526:Isoelectric Point; D008670:Metals; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity; D013696:Temperature
D007477:Ions; D008670:Metals; D002480:Cellulase