Fusion of the leader peptide and the cellulose-binding domain (CBD) of endoglucanase A (CenA) from Cellulomonas fimi, with or without linker sequences, to the N-terminus of alkaline phosphatase (PhoA) from Escherichia coil leads to the accumulation of significant amounts of the CBD-PhoA fusion proteins in the supernatants of E. coli cultures. The fusion proteins can be purified from the supernatants by affinity chromatography on cellulose. The fusion proteins can be desorbed from the cellulose with water or guanidine-HCl. If the sequence IEGR is present between the CBD and PhoA, the CBD can be cleaved from the PhoA with factor Xa. The efficiency of hydrolysis by factor Xa is strongly influenced by the amino acids on either side of the IEGR sequence. The CBD released by factor Xa is removed by adsorption to cellulose. A nonspecific protease from C. fimi, which hydrolyzes native CenA between the CBD and the catalytic domain, may be useful for removing the CBD from some fusion proteins.