Extracellular cellulase production by tropical
isolates of Aureobasidium pullulans. Can. J. Microbiol. Vol. 51, 2005,Cellulase production by Aureobasidium pullulans from the temperate regions has remained speculative,
with most studies reporting no activity at all. In the current study, tropical isolates from diverse sources were
screened for cellulase production. Isolates were grown on a synthetic medium containing cell walls of Msasa tree
(Brachystegia sp.) as the sole carbon source, and their cellulolytic activities were measured using carboxymethyl
cellulose and ?-cellulose as substrates. All isolates studied produced carboxymethyl cellulase (endoglucanase) and
alpha-cellulase (exoglucanase) activity. Endoglucanase-specific activities of ten selected isolates ranged from 2.375
to 12.884 ?mol glucose?(mg protein)?1?h?1, while activities on ?-cellulose (exoglucanase activity) ranged from 0.293
to 22.442 ?mol glucose?(mg protein)?1?day?1. Carboxymethyl cellulose induced the highest cellulase activity in the
selected isolates, while the isolates showed variable responses to nitrogen sources. The current study indicates that
some isolates of A. pullulans of tropical origin produce significant extracellular cellulolytic activity and that crude
cell walls may be good inducers of cellulolytic activity in A. pullulans
