A novel β-glucanase gene from Bacillus halodurans C-125

To examine the activity of the gene product, the gene was cloned as a His-tagged protein and expressed in Escherichia coli. The purified enzyme showed activity against lichenan, barley β-glucan, laminarin, and carboxymethyl curdlan. Thin-layer chromatography showed that the enzyme hydrolyzes substrates in an endo-type manner. When β-glucan was used as a substrate, the pH optimum was between 6 and 8, and the temperature optimum was 60 °C. After 2 h incubation at 50 and 60 °C, the residual activity remained 100% and 50%, respectively. The enzymatic activity was abolished after 30 min incubation at 70 °C. Based on the results, the gene encodes an endo-type β-1,3(4)-d-glucanase (E.C. 3.2.1.6).