Abstract

Production and genetic improvement of novel antimycotic agent, saadamycin, against dermatophytes and other clinical fungi from endophytic Streptomyces sp. Hedaya48

Author(s): Mervat M.A.El-Gendy, Ahmed M.A.EL-Bondkly

As a part of our ongoing efforts towards finding novel antimycotic and other bioactive agents from marine microflora of the Red Sea, recently secondary metabolites secreted by endophytes of some marine corals or sponges in Egypt were investigated. The new bioactive endophytic Streptomyces sp. Hedaya48 was isolated from the Egyptian sponge Aplysina fistularis and identified, which exhibited strong antimycotic activity against dermatophytes and other clinical fungi. Saadamycin [4-(hydroxymethyl)-5- hydroxy-2H-pyran-2-one] a newantimycotic compound, 5,7-dimethoxy-4- -methoxylphenylcoumarin and vanillin were isolated from Streptomyces sp. Hedaya48. The producing strain was subjected to different UV irradiation doses and a mutant strain Ah22 with 10.5-fold higher saadamycin production was isolated (420mg/l as compared to 40mg/l produced by the parental strain). Production of saadamycin frommutantAh22was enhanced to 2.26 -fold (950mg/l) under optimized culture condition in batch culture and 2.38-fold increasing (1000mg/l) in bioreactor more than the yield obtained with the mutant strain Ah22 in normal production medium. Both saadamycin and 5,7-dimethoxy-4--methoxylphenylcoumarinwere exhibited significant antifungal activities against several dermatophytes and other clinical fungal isolates as Aspergillus fumigatus and Candida albicans.