Isolation of Secondary Metabolites From Marine Actinobacterium of Microbispora sp.T3S11 and Their Antibacterial Activities

Abstract

Introduction Marine actinobacteria are promising sources of novel bioactive compounds due to their distinct ecological niches and diverse secondary metabolite production capabilities. Among these, Microbispora sp. T3S11 is notable for its unique spore chain structure, which allows for both morphological and genetic identification. Despite its potential, little is understood about the secondary metabolites produced by this strain. In this study, we hope to fill this gap by extracting and analyzing the antibacterial activities of secondary metabolites from Microbispora sp. T3S11, which will be the first time its bioactive compound profile is investigated. Aim To evaluate the antibacterial activity of secondary metabolites isolated from the marine actinobacterium Microbispora sp. T3S11. Materials and methods The antibacterial assays were carried out on agar plates containing the appropriate media for each pathogen. Sterile filter paper disks were impregnated with secondary metabolites extracted from Microbispora sp. T3S11 and placed on the surface of agar plates inoculated with the appropriate pathogens. Similarly, disks containing tetracycline were used as a positive control. The plates were then incubated at the appropriate temperature for each pathogen, and the zones of inhibition around the disks were measured to determine the extracted metabolites' antibacterial activity. Result Secondary metabolites had antimicrobial activity against Streptococcus mutans, Klebsiella pneumonia, and methicillin-resistant Staphylococcus aureus (MRSA). The inhibition of S. mutans was 7.5 mm and 8.5 mm at 75 μg/mL and 100 μg/mL, respectively. Klebsiella pneumonia zones measured 7 mm and 7.5 mm, while MRSA zones measured 7.6 mm and 8.5 mm at the same concentrations. Tetracycline, the standard antibiotic, had larger inhibition zones: 22 mm for S. mutans and Klebsiella pneumonia and 16 mm for MRSA, indicating variable susceptibility. Conclusion We conclude that the secondary metabolites extracted from Microbispora sp. T3S11 exhibits high antibacterial activity. This could be attributed to the presence of various active compounds.

Keywords: agar disc assay; antibacterial activity; klebsiella pneumoniae; marine actinobacterium; microbispora sp. t3s11; secondary metabolites; staphylococcus aureus; streptococcus mutans.