Isolation, identification and evaluation of 52 fungi from the deep-sea sediments of South China Sea

Abstract:

[Background] Deep-sea environment is complex and diverse with abundant fungi that provide new opportunities to study the chemical and biological activity of deep-sea fungal metabolites. [Objective] To isolate, identify and evaluate fungi from the South China Sea deep-sea sediment, to discover new potential drug source fungi and lay the foundation for further utilization of deep-sea fungi from the South China Sea. [Methods] Based on intergenic transcribed spacer sequencing, 52 fungi isolated from deep-sea sediment were identified. All fungal crude extracts were tested for antibacterial, brine shrimp lethal and antioxidative activities by using Kirby-Bauer test, Solis’ method and DPPH radical scavenging method. [Results] These fungi could be clarified into 16 genera, in which Cladosporium sp. and Aspergillus sp. were in majority, accounting for 25.00% and 23.08%, respectively; 32 strains inhibited 1 indicative bacterium at least, 8 of which inhibited all 4 indicative bacteria; 23 strains exhibited medium brine shrimp lethality, accounting for 44.23% of all isolated strains, 2 of which exhibited obvious activities with IC50 of 68.59, 78.83 μg/mL; 30 strains showed DPPH radical scavenging activity, accounting for 57.69%, 9 of which with EC50 values lower than 100 μg/mL. [Conclusion] This study revealed the distribution and metabolite activities of deep-sea fungi from South China Sea and found a number of potential active fungi, and provides support for subsequent investigation on chemical diversities and biological activities of deep-sea fungi.

Key words:Deep-sea fungus, Identification, Antibacterial activity, Brine shrimp lethality, Antioxidative activity