Isolation and Characterization of Antifungal Agent(s) from Local Microbial Isolate(s) / Donia Hosni Mohamed Sheir ; Supervised Alaa Eldien M. S. Hosny , Ahmed Ibrahim Eldiwany

Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

The aim of this work was isolation of new antifungal agents producer microorganisms especially the Genus Streptomyces from which the majority of the antibiotic and antifungal agents are found (Raja and Prabakarana, 2011). Out of the forty Streptomyces that were isolated, two promising Streptomyces isolates coded 4 and 40 showed potent antifungal activity upon performing screening studies and they were further evaluated against clinical Candida isolates. Streptomyces spp. 4 and 40 were characterized morphologically, physiologically and biochemically which was confirmed by API system. In addition, molecular identification using 16S rRNA and BLAST analysis were performed. Results showed that Streptomyces spp. 4 and 40 were identified as S. atrovirens (strain H33) and S. lusitanus (strain D80) and both were deposited in the Genbank data base under accession numbers of KJ435269 and KJ609202 respectively. However, The effect of crude extracts of S. atrovirens H33 and S. lusitanus D80 as anti-Candida biofilm using resazurin assay was evaluated under optimized biofilm conditions. Results revealed that, only crude extract of S. lusitanus D80 showed anti-Candida biofilm activities in both prevention and destruction modes. Submerged fermentation using 7L bioreactor was used for production of antifungal agents by S. atrovirens H33 and S. lusitanus D80 under the following conditions: Starch casein broth medium 5 L, temperature of 30{u00BA}C, aeration of 5 vvm and agitation of 400 rpm. Themaximum antifungal production was reached after 66 and 60 h giving inhibition zone of 26 and 22 mm for S. atrovirens H33 and S. lusitanus D80 respectively

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