ABSTRACT
Fourteen isolates, members of the Ascobolaceae family, representing two widespread genera, Ascobolus and Saccobolus, were obtained from dung of herbivorous animals. All the isolates were capable of growing and producing clearing zones in CMC agar media. The species of Ascobolus gave larger clearing zones than the species of Saccobolus. S. verrucisporus and S. longevisporus were the most cellulolytic species in this genera while A. bistisii was the most cellulolytic among all the species tested. The results obtained showed that more than one method of screening must be employed to analyse the cellulolytic ability of different species.
Subject(s)
Ascomycota/metabolism , Cellulase/metabolism , Cellulose/metabolism , Feces/microbiology , Fungal Proteins/metabolism , Animals , Ascomycota/classification , Species SpecificityABSTRACT
Growth and cellulase-xylanase enzyme systems production by Ascobolus gamundii were evaluated in synthetic media with or without natural inducers. The basal level of enzyme complexes was determined using glucose as carbon source. With crystalline cellulose, the amount of endoglucanase and beta-glucosidase was 2-4 times the basal, and the level of endoxylanase and beta-xylosidase was 3 times higher than that observed with glucose. When using xylan as carbon source, endoxylanase and endoglucanase were induced. The higher production of the enzyme systems was observed during the log-phase growth of A. gamundii with a mixture of cellulose and xylan as carbon source. The generalized induction of both enzyme complexes could be due to evolutive adaptation to the substrate (herbivore dung) in which cellulose and hemicellulose are associated to conform the plants cell-walls.
