Antagonistic and Antioxidant Potential of Actinomycete Isolates from Sambhar Lake

Bacterial secondary metabolites contain a diverse spectrum of biologically active compounds, including antimicrobials and antioxidants. Harnessing these products has enabled humans to fight against various diseases. But due to the overuse of antibiotics over the past few decades, many resistant strains of microbes are emerging. Therefore, there is a need to identify new sources of antimicrobial compounds. Actinomycetes are a group of bacteria known to produce antimicrobial compounds. This investigation aimed to identify, isolate and characterize actinomycetes with antimicrobial and antioxidant activity against pathogens acquired from MTCC. Sambhar Lake has a very potential group of actinomycetes producing several secondary metabolites. The study reports the antimicrobial and antioxidant potential of different extracts of actinomycetes. The sections of the actinomycetes were tested for their antagonistic activity against five pathogenic microorganisms. Antibacterial activity was reported in all five actinomycete isolates against Bacillus subtilis-MTCC 441, Escherichia coli-MTCC-1885, and Salmonella typhi-MTCC 733 but almost negligible activity against Staphylococcus aureus-MTCC 737 and Pseudomonas aeruginosa- MTCC 424 except for ACT-14 and ACT- 11. ACT14 had the highest antibacterial activity compared to all other isolates. The antioxidant capacities of all isolated extracts were evaluated for total phenols, total antioxidant activity, total reducing power, DPPH, and ABTS assays. Section of Pseudonocardia Antarctica ACT14 showed the highest (23.89±0.96) free radical scavenging of 2, 2-diphenyl1-picrylhydrazyl (DPPH), phenolic activity (194 ± 6.05) activity. This study was conducted to identify novel actinomycetes with antimicrobial properties. The sample ACT14 was found to be a novel actinomycete (Pseudonocardia Antarctica), and this isolate showed antimicrobial activity against all the test pathogenic bacteria used in the study. The culture was optimized for antimicrobial compound production. Since many pathogens tend to acquire antibiotic resistance, this study is essential as a novel source of antimicrobials that will provide a new weapon in the fight against infectious pathogens. Further purification and characterization of this compound are underway. 