Objective: The aim of the study was to evaluate antibacterial and antioxidant potential of the
actinomycete isolate Streptomyces laurentii strain VITMPS isolated from marine soil, Chennai, Tamil
Methods: The antibacterial activity of crude extract was tested against two bacterial pathogens and the
DPPH assay was determined for free radical scavenging potential. The morphological, physiological and
the biochemical properties of the strain VITMPS was confirmed by conventional methods and genotypic
characterization were carried out using 16SrDNA partial gene sequencing.
Results: The strain VITMPS was identified as Streptomyces spp. on biochemical and morphological characterization.
Phylogenetic tree was constructed and the 16S rRNA gene sequence showed 99% similarity
to Streptomyces laurentii strain NBRC 15422. The antibacterial activity studied was found to exhibit the
maximum spectra of activity at 1mg/mL concentration against Bacillus cereus (35 mm) Escherichia coli
(35 mm). The lowest Minimum Inhibitory Concentration (MIC) of the crude extract against Bacillus
cereus (MTCC No: 6840) and Escherichia coli (MTCC No: 1588) was found at 100 µg mL-1
The ethyl acetate extract possessed DPPH free radical scavenging activity at 1 mg/ mL with 83%
Conclusion: The antibacterial and antioxidant activity of the extract clearly indicates the marine environment
is the vast sources for the isolation of bioactive compounds from actinomycetes.