Antibacterial Activities and Toxicity of Streptosporangium sp. SM1P

Risa Nofiani,Ridho Brilliantoro,Rizky Rizky

doi:10.20884/1.jm.2021.16.3.780

Abstract

This study aims to explore the anti-bacterial and toxicity activities from a rare actinobacterium isolated from mangrove, Mempawah District, West Kalimantan. The mangrove mud sample from Mempawah district was inoculated on ISP4 agar using a pour plate method. After 4 days of incubation, a colony of suspected actinobacterium was appeared, then isolated and coded as SM1P. SM1P was characterized based on morphological and biochemical traits and identified as a genus of Streptroporangium then called Streptroporangium sp. SM1P. Streptroporangium sp. SM1P was carried out anti-bacterial assay on both ISP1 agar and ISP4 agar media using the cross-streak method for the solid-state fermentation. The result showed that Streptroporangium sp. SM1P could inhibit Streptococcus sp. and Salmonella typhi on ISP1 agar and treptococcus sp., Escherichia coli, Vibrio cholerae, Staphylococcus aureus and Salmonella typhi on ISP4 agar. Streptroporangium sp. SM1P was cultivated on ISP1 broth and extracted using ethyl acetate, then evaporated to obtain crude extract. The crude extract was used for anti-bacterial assay (well-diffusion method for liquid-state fermentation) and toxicity assay (brine shrimp lethality test). The crude extract was active against 2 of the test bacteria (Streptococcus sp. and E. coli). The best medium and state fermentation for anti-bacterial assay were ISP4 agar with the condition of solid-state fermentation. The extract SM1P prepared on ISP1 broth showed toxic activity based on LC50 (106.094 µg/mL). Therefore, Streptroporangium sp. SM1P have a potential source to explore secondary metabolites having anti-bacterial and toxicity activities.

Highlights

Actinobacteria or actinomycetes are Gram-positive bacteria that have high G+C content
Isolation and Characterization of the Isolate SM1P was one of two isolates that appeared on day four at the surface of ISP4 agar supplemented with meropenem and nystatin
A small powdery colony, SM1P, was suspected as an actinobacterial characteristic that was rich in secondary metabolites with various biological activities

Summary

Introduction

Actinobacteria or actinomycetes are Gram-positive bacteria that have high G+C content. Many members of the genus actinobacteria can produce various secondary metabolites having broad range biological activities, such as antimicrobial, antitumour, antiparasitic and immunosuppressive activities. This phylum has received more attention from most researchers that focus on exploring secondary metabolites, from Streptomyces sp. Has been continually explored secondary metabolites by scientists, which often causes reisolation of known secondary metabolites. Most scientists use rare actinobacteria as secondary metabolite producers to avoid re-isolation of known secondary metabolites. Rare actinobacteria are categorized if actinobacteria abundance are lower than Streptomyces abundance such as Streptosporangium sp. Rare actinobacteria are reported by scientists producing novel secondary metabolites with various biological activities (Azman, Othman, Velu, Chan, & Lee, 2015)

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