A recombinant cellulolytic Escherichia coli: Cloning of the cellulase geneand characterization of a bifunctional cellulase

A genomic library of Bacillus subtilis CD4 was constructed in Escherichia c oli JM83. A clone designated as E. coli pBcelR was identified which formed blue colony in presence of 5-bromo-4-chloro-3-indolyl-beta-D-glucopyranosid e (X-Glu) and hydrolysed carboxymethyl cellulose (CMC). The clone E. coli ( pBcelR) expressed both cellobiase and endoglucanase activities and containe d an insert of 1.2 kb. E. coli pBcelR encoded a protein of 12.9 kDa which w as endowed with bifunctional (endoglucanase and cellobiase) activities. In recombinant E. coli, the encoded protein and enzyme activity were localized in periplasm. Recombinant E. coli pBcelR utilized CMC, cellobiose and solu ble cellulose as sole carbon source.