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

A Arjunan,C Nivetha,M Muthuselvam,N Revathi,P Sivalingam,T Deepika

doi:10.9734/jpri/2021/v33i50b33445

A Arjunan, C Nivetha + Show 4 more

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https://doi.org/10.9734/jpri/2021/v33i50b33445

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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.

Highlights

Soil is the complex combination of minerals, organic substances, gases and liquids
Researchers are still actively researching the diversity of the microbial community in the phylum Actinobacteria originating from various environments, often due to their ecological significance and biotechnological benefits [48,49,50]
The physiochemical parameters and nutrient content of selected samples were estimated using different analytical methods and the results were representing in Table 1 and Fig. 1

Summary

Introduction

Soil is the complex combination of minerals, organic substances, gases and liquids. There are numerous micro and macro organisms in soil that sustain a wide variety of plant life. Soil quality is essential to forest management because of its influence in ecosystem processes and structure [1,2,3]. There are a number of parameters like pH, temperature, soil type, salinity, organic matter, cultivation, aeration and moisture content that must be monitored in order to determine the pollution load in an area [4]. Muthupettai mangrove ecosystem is largely unexplored which provides a rich source of the microorganisms that create unique and potent antimicrobial compounds. Actinobacteria are Gram-positive, aerobic, sporeforming bacteria that contain high level of GC and widely distributed in nature. They form extensive branching aerial and substrate mycelia. Volatile products secreted by Streptomyces may be responsible for the characteristic smell [7]

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