Morphological, Molecular and Biochemical Comparative Studies of Two Novel Fungal Honey Isolates

Abstract

Aims and Study Design: The stress honey medium expected to have spores with unique feature. Within this context, two honey isolates were identified, characterized, and evaluated as secondary metabolite producers. Place and Duration of Study: The study was undertaken in the National research center, 33 Al Behous, Dokki, Giza, Egypt. The duration of study was during the period of January 2012 to February 2013. Methodology: Two strains were isolated from mountain honey, Yemen. They were identified based on morphological characterization and 18S rRNA sequence analysis. Validation of novelty was supported further by their protein profile and randomly amplified polymorphic DNA PCR patterns (RAPD). Growth parameters were studied to determine optimum growth factors. In addition, they were undergone to enzymatic, antibiotic, antioxidant, ochratoxins and aflatoxins testes. Results: Two novel honey isolates were identified and designed as Aspergillus niger EM77 and Aspergillus awamori EM66. Intracellular protein profiles showed clear difference among the honey isolates and their references. The RAPD referred to 51% coincidence between the two isolates and showed different RAPD patterns between the references and honey isolates. Different parameters which affected isolates growth such as pH, temp, carbon and nitrogen sources were studied. Effect of NaCl concentrations referred to the halo-tolerant feature of both isolates. Both strains showed strong antimicrobial activity against Candida albicans, C. tropicalis and Pseudomonas species. Reducing power assay reported 82% and 83% antioxidant activity of Aspergillus niger EM77 and A. awamori EM66, respectively. Aflatoxins and ocratoxins tests revealed that both isolates had negative results. In addition, two fungal honey isolates showed relatively similar enzymatic activities. Conclusion: This research continues in highlights the honey as a new reservoir of unique isolates. In addition, it was suggested that the honey osmophilic stress carried spores have novel properties.