Affinity digestion for the near-total recovery of purified cellulosome from Clostridium thermocellum

The affinity properties displayed by the cellulosome, the multienzyme complex from Clostridium thermocellum, for its insoluble polymeric substrate, cellulose, have previously been employed for its purification by affinity chromatography. In the present communication, a new purification procedure is described which provides five-fold higher yields (>90%) of the cellulosome with enhanced solubilizing activity (approximately 1.5-fold). The new method is based on the efficient adsorption of the cellulosome onto phosphoric acid-treated substrate (amorphous cellulose) and the subsequent digestion of the carrier/substrate by the adsorbed enzyme complex. The term "affinity digestion" is proposed for such systems in which the affinity matrix is degraded totally by the adsorbed enzyme(s), thus facilitating its recovery.