Evaluation of antimicrobial metabolites produced by Arthrobacter kerguelensis VL-RK_09 by GC-MS analysis

Abstract

The purpose of the present study was concerned with the isolation and characterization of a rare actinobacterial strain designated as VL-RK_09 from a Mango orchard and evaluation of its antimicrobial compounds by GC-MS analysis. Soil dilution plate technique was employed for the isolation of the strain on yeast extract malt extract dextrose (YMD) agar medium. The strain was identified as Arthrobacter kerguelensis based on polyphasic taxonomy. Suitable culture media for the production of antimicrobial metabolites was assessed by inoculating the strain in different ISP (International Streptomyces project) media and non ISP media. The culture broth of the strain grown in best suitable medium (ISP-2) was extracted with different solvents viz., chloroform, ethyl acetate, methanol and acetone. The culture broth inoculated in ISP-2 and extracted with ethyl acetate exhibited strong antimicrobial activity against oppurtunistic pathogenic microorganisms tested. The crude ethyl acetate extract exhibiting high antimicrobial activity was analysed by Gas Chromatography-Mass Spectroscopy to reveal the metabolites produced by the strain and evidenced the presence of 39 compounds according to the available library data, NIST MS Search (ver. 2.0). The results of the present study revealed the production of diversified metabolites by the strain and hence this strain could be a possible source for novel antimicrobial compounds.

Keywords

• Arthrobacter kerguelensis,antimicrobial metabolites,gas chromatography,International Streptomyces Project,mass spectroscopy,polyphasic taxonomy

References

1. Baltz, R.H. Antibiotic discovery from actinomy-cetes: will a renaissance follow the decline and fall? SIM News 2005; 55, 186-196.