Journal Article

Purification and characterization of a family 5 endoglucanase from a moderately thermophilic strain of Bacillus licheniformis

Rooney, Alejandro P, Li, Xin-Liang, Hughes, Stephen R, Bischoff, Kenneth M, Liu, Siqing

2006

Overview

Strains of thermophilic bacilli were screened for cellulolytic activity by gel diffusion assay on selective medium at 55°C. Strain B-41361, identified as a strain of Bacillus licheniformis, displayed activity against carboxymethylcellulose. Zymogram analysis demonstrated several catalytically active polypeptides with the most prominent species having a mass of 37 kDa. The enzyme was purified 60-fold with a 17% yield and specific activity of 183 U/mg. The amino terminal sequence was homologous to members of glycoside hydrolase family 5. Optimal temperature was 65°C (measured over 30 min), but the enzyme was most stable at 60°C, retaining greater than 90% activity after one hour. The enzyme had a broad pH range, with maximal activity at pH 6.0, 75% maximal activity at pH 4.5, and 40% at pH 10. The enzyme hydrolyzed p-nitrophenylcellobioside, barley β-glucan, and lichenan, but no activity was detected against avicel or acid-swollen cellulose.

• Publisher: Dordrecht : Kluwer Academic Publishers,Springer,Springer Nature B.V
• Subject: amino acid sequences / Bacillus / Bacillus - enzymology / Bacillus licheniformis / Bacteria / beta-glucans / Biological and medical sciences / Biotechnology / carboxymethylcellulose / Cellulase / Cellulase - chemistry / Cellulase - isolation & purification / Cellulase - metabolism / Cellulose / chemistry / endo-1,4-beta-glucanase / enzymatic hydrolysis / enzyme activity / Enzyme Stability / enzymology / Fundamental and applied biological sciences. Psychology / Hordeum vulgare / isolation & purification / lichenan / metabolism / Molecular Sequence Data / molecular weight / purification / Sequence Alignment / Sequence Analysis, Protein / Substrate Specificity / thermophilic bacteria