Screening, isolation and study of antifungal activity of marine actinomycetes from Deylam nearshore sediments

Abstract

Background: Marine actinomycetes, gram positive bacteria, have been prolific sources of novel secondary metabolites with a range of biological antibacterial activities. Marine sediments are potential sources for isolation of novel actinomycetes yielding new products and are recognized as source of novel antibiotic. In this study, we reported the isolation, characterization and antifungal activities of 8 actinomycetes isolated from Deylam nearshore sediments. Materials and Methods: The marine soil sediment samples were collected from Deylam nearshore at the depth of 10 cm. The treated samples were serially diluted and used starch casein agar as a culture medium. Morphological and biochemical characterization of isolated strain was carried out by using standard methods. Antifungal assay of the bacterial extracts was performed using standard well diffusion assay. Results: In this study, 8 marine actinomycetes were isolated from Deylam near shore sediments according to their morphology. All of isolate was belonged to Streptomyces genus. Differential analyses results for catalase and Gram test were positive for all isolates, the positive isolates for TSI, simmon citrate and ornitin decarboxylase were 1, 2 and 5 respectively, all isolates were negative for lysine decarboxylase, VP, MR and indol test, SIM test results showed that all isolates were non-motile, one isolate was produced H2S and some isolates formed pigmented colony. Most isolates showed antifungal activity against tested pathogenic fungi. Conclusion: Results of this investigation revealed that the marine actinomycetes of Deylam nearshore sediments were potent source of bioactive compounds with antifungal activity.

Keywords

• Marine actinomycetes
• Deylam nearshore
• Antifungal activity