Available online at : www.refaad.com/CRMI CRMI 1(1) (2020) : 5-13 A Potential Bioactive Secondary Metabolites and Antimicrobial Efficacy of Streptomyces thermocarboxydus Strain KSA-2, Isolated from Kali River, Karwar Sreenivasa Nayaka *a , Muthuraj R. b , Bidhayak Chakraborty b , Meghashyama Prabhakara Bhat b , Pallavi S.S. b , Shashiraj K.N. b , Halaswamy H.M. b , Dhanyakumara S.B. b , Dattatraya Airodagi. b , Kavitha Haged c . a Assistant Professor, Dept. of P.G. studies in Botany, Karnatak University Dharwad, Karnataka, India. b Research scholar Dept. of P.G. studies in Botany, Karnatak University, Dharwad, Karnataka, India. c M.Sc. Dept. of P.G. studies in Botany, Karnatak University, Dharwad, Karnataka, India. E-mail: a sreenivasanayaka06@gmail.com Received: 30 th Mar2020 Revised: 27 h May 2020 Accepted: 8 th sept 2020 DOI: https://doi.org/10.31559/CRMI2020.1.1.2 * Corresponding author Sreenivasa Nayaka Assistant Professor, Dept. of P.G. studies in Botany, Karnatak University Dharwad, Karnataka, India. E-mail: sreenivasanayaka06@gmail.com www.refaad.com Current Research in Microbiology and Infection (CRMI) Journal Homepage: https://www.refaad.com/views/CRMI/home.aspx Abstract: In the present study, an Actinomycetes strain KSA-2 was isolated from freshwater sediment samples of Kali River, Karwar, Karnataka, India. The strain KSA-2 was selected among seven isolates based on primary screening of antimicrobial activity against pathogenic organisms. The morphological physiological and biochemical characterizations were performed, the bioactive secondary metabolites were produced in liquid broth culture and was characterized by UV-Vis. spectroscopy and FTIR spectroscopy. Later, the potent KSA-2 strain was identified by 16S rRNA gene sequencing (1366 bp) and a phylogenetic tree was constructed and the strain KSA-2 was confirmed as Streptomyces thermocarboxydus strain KSA-2. Further, the characterization of methanolic extract by UV-Vis. and FTIR spectroscopy analysis revealed the presence of broad spectrum of antimicrobial and other compounds and alkyl halides, alkenes, sulfoxide, carboxylic acids, alkanes respectively. Keywords: Streptomyces thermocarboxydus; antimicrobial activity; FTIR; 16S rRNA gene sequencing; phylogenetic tree.