Antimicrobial and Antioxidant Activities of Streptomyces sps Isolated from Muthupettai Mangrove Soil

Abstract

Muthupet mangrove forest soil sediment was the abundant resource of the actinomycetes with distinct nature of bioactive compounds. The soil sediment was collected at 1-3meter away from bank. The present study was focused on isolation, identification and antimicrobial activity of the actinomycetes from Muthupet mangrove soil samples. Totally 32 actinomycetes strains was isolated and screened for antimicrobial activity against bacterial and fungal pathogens. Among 32 isolates 16 have antibacterial activity and 10 have antifungal activity but MG-3 and MG-4 showed maximum activity against both all the test pathogens. These two strains are gram-positive, rod-shaped, MG-3 possessing an earthy characteristic odour and MG-4 produce purple color pigment. The isolates were confirmed as Streptomyces sp. based on morphological, cultural, biochemical and physiological observations, as well as identification using the 16S rRNA gene sequence, it showed 98% similarity with Streptomyces parvus for MG-3 and Streptomyces californicus for MG-4. Bioactive compounds were extracted from Streptomyces using different solvents such as ethyl acetate, methanol, chloroform, hexane and antibacterial activities were assayed against test pathogens, ethyl acetate extract showed maximum zone of inhibition when compared with other solvents. The Minimum inhibitory concentration of ethyl acetate extract was found ranged between 1.96-3.9 μg/ml. The invitro antioxidant capacity of the crude extract was estimated by DPPH, ferric reducing power assay, H202 radical scavenging assay, phosphomolybdenum assay and total antioxidant activities. The characterization of crude extracts was analyzed by FTIR and GC-MS. From the results, it is clear that the ethyl acetate crude extract of S.parvus MG-3 and S.californicus MG-4 possesses high antimicrobial and antioxidant activity and suggested that the isolated strains could be a potential for the nature resource of pharmaceutical.