Clostridium thermocellum Cel5L – Cloning and Characterization of a New, Thermostable GH5 Cellulase.

Aims: Clostridium thermoc ellum is a thermophilic, anaerobic bacterium that ferments cellulose and produces ethanol. While many of the predicted cellulases have been characterized from C. thermocellum , characte rization of additional members is still needed to unravel the function of these enzymes. Study Design : This report describes the first cloning, expression, characterization, and evaluation in cellulose degradation of Clostridium thermocellum Cel5L as well as its relationship to other cellulases. Results: Cel5L, a 526 amin o acid protein that shows low homology to other cellulases of C. thermocellum , possesses both endo and exo activity on  - glucan, carboxymethylcellulose, and cellooligosaccharides; the enzyme does not hydrolyze xylan, xyloglucan or glucomannan. When