Optimization of Culture Conditions for Enhanced Antimicrobial Activity of Rhodococcus erythropolis VLK-12 Isolated from South Coast of Andhra Pradesh, India
Krishna Naragani
Department of Botany and Microbiology, Acharya Nagarjuna University, Guntur-522510, Andhra Pradesh, India.
Rajesh Kumar Munaganti
Department of Botany and Microbiology, Acharya Nagarjuna University, Guntur-522510, Andhra Pradesh, India.
Usha Kiranmayi Mangamuri
Department of Botany and Microbiology, Acharya Nagarjuna University, Guntur-522510, Andhra Pradesh, India.
Vijayalakshmi Muvva *
Department of Botany and Microbiology, Acharya Nagarjuna University, Guntur-522510, Andhra Pradesh, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: To Isolate and characterize the antimicrobial actinomycetes from the marine habitats of south coast of Andhra Pradesh, India.
Place and Duration of the Study: Marine habitats of south coast of Andhra Pradesh, India, between June 2011 and July 2012.
Methodology: The soil samples were collected, pre-treated and plated on yeast extract- malt extract dextrose agar medium. Identification of the strain was carried out by employing the polyphasic taxonomical studies including the 16S rRNA sequence based analysis. Phylogenetic tree was constructed using the Molecular Evolutionary Genetic Analysis (MEGA) version 5. The influence of culture conditions and the effect of environmental factors on the biomass and antimicrobial activy\ity of the strain was the focus of this study.
Results: A total of 20 actinobacteria were isolated from the marine habitats of south coast of Andhra Pradesh, India, and screened for antimicrobial activity against test bacteria and fungi. The potent bioactive metabolite producing strain was designated as VLK-12. Further polyphasic studies revealed that the Isolate VLK-12 belongs to the genera Rhodococcus. Phylogenetic analysis of 16S rRNA sequencing studies revealed that the strain is closely related to Rhodococcus erythropolis. The crude ethyl acetate extract obtained by culturing the strain on YMD inhibited Gram positive and Gram negative bacteria along with fungi.
Conclusion: Rhodococcus erythropolis isolated from the marine habitats of south coast of Andhra Pradesh exhibited antimicrobial activity against pathogens.
Keywords: Rhodococcus erythropolis, antimicrobial profile, bioactive metabolites, nutritional factors, culture conditions and environmental parameters