Molecular cloning and expression in Escherichia coli of a thermophilic Bacillus sp. PDV endo-β-1,4-glucanase gene

Abstract

The gene encoding endoglucanase in thermophilic Bacillus sp. PDV was cloned in Escherichia coli strain TB1 using pUC 8 as vector. The cloned 3.1 kb PstI DNA fragment was found to express the endoglucanase activity in either orientation. The deletion analysis of pSD 81 suggested that the Bacillus endoglucanase gene expressed in E. coli under the control of its own natural promoter, contained putatively in the 0.2 kb HindIII fragment at the 5′ end of the insert. The relative level of endoglucanase expression in E. coli was about three times higher than that in parent Bacillus sp. PDV. The cloned organism secreted about 84% of the total synthesized CMCase into the culture medium. The CMCase was stable up to 60°C and in the pH range of 4–10.