Acta Microbiologica et Immunologica Hungarica, 63 (1), pp. 27–46 (2016) DOI: 10.1556/030.63.2016.1.2 1217-8950/$20.00 © 2016 Akadémiai Kiadó, Budapest ANTIMICROBIAL ACTIVITY AND PHYLOGENETIC ANALYSIS OF STREPTOMYCES PARVULUS DOSMB-D105 ISOLATED FROM THE MANGROVE SEDIMENTS OF ANDAMAN ISLANDS R. BASKARAN 1 *, P. M. MOHAN 1 , K. SIVAKUMAR 2 , ASHOK KUMAR 3 1 Department of Ocean Studies and Marine Biology, Pondicherry University, Brookshabad Campus, Port Blair-744 112, Andaman Island, India 2 CAS in Marin Biology, Annamalai University, Parangipattai, Tamil Nadu-608 502, India 3 Department of Biotechnology, Himachal Pradesh University, Summer Hill, Shimla, India-171 005 (Received 30 June 2015; accepted: 10 December 2015) Actinomycetes, especially species of Streptomyces are prolific producers of pharmacologically significant compounds accounting for about 70% of the naturally derived antibiotics that are presently in clinical use. In this study, we used five sol- vents to extract the secondary metabolites from marine Streptomyces parvulus DOSMB-D105, which was isolated from the mangrove sediments of the South Andaman Islands. Among them, ethyl acetate crude extract showed maximum ac- tivity against 11 pathogenic bacteria and six fungi. Presence of bioactive compounds in the ethyl acetate extract was determined using GC-MS and the compounds de- tected in the ethyl acetate extract were matched with the National Institute of Stand- ards and Technology (NIST) library. Totally eight compounds were identified and the prevalent compounds were 2 steroids, 2 alkaloids, 2 plasticizers, 1 phenolic and 1 alkane. Present study revealed that S. parvulus DOSMB-D105 is a promising spe- cies for the isolation of valuable bioactive compounds to combat pathogenic mi- crobes. Keywords: antimicrobial activity, bioactive compound, actinobacteria, Streptomyces parvulus, Andaman Islands Introduction Status of marine sources for unearthing the novel natural products with pharmaceutical potential has been brought out during the last decade and high- *Corresponding author; E-mail: sivan.thamilan@gmail.com