Richness of endophytic fungi isolated from Opuntia ficus-indica Mill. (Cactaceae) and preliminary screening for enzyme production

摘要

Opuntia ficus-indica Mill. (forage cactus) is farmed with relative success in the semi-arid region of the Brazilian northeast for commercial purposes, particularly as forage and food. Endophytic microorganisms are those that can be isolated inside plant tissues and can be a new source to production of enzymes with different potentialities. The objective of this study was to describe the richness of endophytic fungi from O. ficus-indica and to detect the capacity of these species to produce extracellular hydrolytic enzymes. Forty-four endophytic fungi species were isolated. Among them, the most commonly found were Cladosporium cladosporioides (20.43%) and C. sphaerospermum (15.99%). Acremonium terricola, Monodictys castaneae, Penicillium glandicola, Phoma tropica and Tetraploa aristata are being reported for the first time as endophytic fungi for Brazil. The majority of isolated fungi exhibited enzymatic potential. Aspergillus japonicus and P. glandicola presented pectinolytic activity. Xylaria sp. was the most important among the other 14 species with positive cellulase activity. All 24 isolates analysed were xylanase-positive. Protease was best produced by isolate PF103. The results indicate that there is a significant richness of endophytic fungi in O. ficus-indica, and that these isolates indicate promising potential for deployment in biotechnological processes involving production of pectinases, cellulases, xylanases and proteases.