Cloning and Expression in Escherichia coli of Thermophilic Clostridium sp. Fl Genes Related to Cellulose Hydrolysis

Abstract

Eleven distinct fragments of Clostridium sp. stain Fl (which was isolated and identified in this laboratory) DNA have been cloned in E. coli and shown to express enzymatic activities related to cellulose hydrolysis. Six of the 11 E. coli clones showed endoglucanase activity, 2 showed cellobiohydrolase activity as well as endoglycanase activity, one showed β-glucosidase activity and the 2 others showed exoglucanase activity as well as xylanase activity. On comparing the restriction maps of the plasmids constructed in this study with those of C. thermocellum genes, it was concluded that 7 of the 11 clones carried hitherto unidentified cellulase genes, i.e., 4 endoglucanase genes, 1β-glucosidase gene and 2 xylanase/exoglucanase genes, and that the 4 other clones carried the same genes as those found in C. thermocellum.