Cellulase isoenzyme profiles in Frankia strains belonging to different cross-inoculation groups

Carboxymethyl cellulase activities were evaluated in eight strains of Frankia from diverse host specificity groups and geographical origins. Cellulase activity was detected in culture supernatants of all strains in the absence of CMC (Carboxymethylcellulose) as an inducer using both double-layer plate and reducing sugar assays, indicating a constitutive production of CM-cellulases by Frankia. CM-cellulase isoenzyme profiles were visualized using activity gel electrophoresis of concentrated culture supernatants. Different electrophoretic profiles were observed among the eight strains tested, which correlate with the host specificity and taxonomic grouping of Frankia.