REGULATION OF BIOSYNTHESIS OF INDIVIDUAL CELLULASES IN THERMOMONOSPORA-FUSCA

Regulation of the biosynthesis of the six cellulases comprising the ce llulolytic system of the thermophilic soil bacterium Thermomonospora f usca ER1 was studied. The levels of the individual enzymes produced on different noninducing and inducing carbon sources were determined. Th e lowest level of cellulase synthesis (3 nM) was observed with xylose as a carbon source, and the highest level (247 to 1,670 nM for differe nt enzymes) was found in cultures grown on microcrystalline cellulose. Endocellulases and exocellulases shelved distinctly different regulat ion patterns. Differences in the regulation of individual enzymes appe ar to be determined by the specific structural organization of the ups tream regulatory sequences of their genes.