Expression of an endoglucanase gene fromClostridium cellulolyticum inEscherichia coli

A gene coding for an endoglucanase from the anaerobic cellulolytic bacteriumClostridium cellulolyticum has been cloned by direct selection inEscherichia coli, using the carboxymethyl cellulose-Congo Red assay. The cloned gene has been subcloned in the two possible orientations in pUC plasmids. One of the two resulting constructs exhibited a higher level of expression, which was associated with a high level of plasmid instability. The enzyme synthesized inE. coli from the cloned gene has been characterized by two procedures, maxicells and gel filtration chromatography, as a polypeptide of approximately 40 kilodaltons.