Cellulolytic activity of fungi isolated from anise and cumin spices and potential of their oils as antifungal agents

摘要

Mycological analysis of 100 samples of anise and cumin seeds collected from four governorates (Aswan, Qena, Sohag and Assiut) in Upper Egypt revealed the isolation of seventy-one fungal species belonging to 30 genera. Anise seeds yielded a wider spectrum of fungal species (51 species) than those of cumin (41 species) using diluted seed suspension cultured on glucose- and cellulose-Czapek`s agar. The most common fungal species isolated from anise and cumin seeds were?Alternaria alternata,?Aspergillus flavus,Aspergillus fumigatus,?Aspergillus niger,?Aspergillus sydowii,?Aspergillus terreus,Emericella nidulans,?Mucor hiemalis,?Penicillium chrysogenum,?Stachybotrys pomiformisand?Sterile mycelia. The ability of 71 fungal species recovered from both anise and cumin seeds to produce cellulases (exo- and endo-β-1,4-glucanase) on solid media was studied.A. flavus?and?Mucor circinelloides?were the most active cellulase producers, so they were chosen to determine the best favorable environmental and nutritional conditions for exo- and endo-β-1,4-glucanase production. Maximum production of exo- β-1,4-glucanase by?M. circinelloides?was recorded after 6 days of incubation at 30°C and initial pH 6 with incorporation of fructose and potassium or sodium nitrate as carbon and nitrogen sources, respectively. However, maximum yield of endo-β-1,4-glucanase by?A. flavus?was obtained after 6 days of incubation at 30°C and initial pH 6 with medium containing sucrose and sodium nitrate as carbon and nitrogen sources, respectively.?In vitro?inhibitory effect of essential oils extracted from anise and cumin seeds were tested against the mycelial growth of 71 fungal isolates. Cumin oil was highly effective causing complete inhibition of all tested fungal isolates. Anise oil completely inhibited 62% and showed varying degrees of activity towards 38% of total isolates.