Journal of Pure and Applied MicrobiologyVol. 8 No. May 2014 Special Edition

Identification of Polyketide Gene from Streptomyces roseoverticillatus and Its Antimicrobial Properties against Pathogenic Bacteria and Fungi

Mariadhas Valan Arasu1, Thankappan Sarasam Rejiniemon2, V. Aldous J. Huxley2, Soundarrajan Ilavenil6, Veeramuthu Duraipandiyan1, Naif Abdullah Al-Dhabi1, Da Hye Kim3,4, Kyung Dong Lee5 and Ki Choon Choi6*

1Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia. 2Department of Zoology, Thiru Vika Government Arts College, Thiruvarur - 610 003, Tamil Nadu, India. 3The United Graduate School of Agricultural Sciences, Tottori University, Tottori-Shi, 680-8553, Japan. 4Faculty of Life and Environmental Science, Shimane University, Matsue-Shi, 690-8504, Japan. 5Department of Oriental Medicine Materials, Dongsin University, Naju, Republic of Korea. 6Grassland and forage division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam, 330-801, Republic of Korea.

Received on 28 February 2014 and accepted on 02 May 2014



The aim of this study was isolation and characterization of antimicrobial metabolite producing actinomycetes from forest soil. A new actinomycete designated ERIAS-10 was selected based on antibacterial and antifungal activity in the primary screening. Biochemical, physiological, morphological and carbohydrate fermentation pattern of the isolate was characterized and confirmed that the isolate belong to Strepomyces species. The 16S rRNA gene sequence shared 100% sequence similarity to Streptomyces roseoverticillatus. The antimicrobial substances were extracted with organic solvents from the spent medium in which ERIAS-10 was cultivated. Antimicrobial activity was assessed using the broth micro dilution technique. The minimum inhibitory concentration (MIC) of the extracts against Enterococcus faecalis was 7.81 ?g/mL and Aspergillus niger, A. flavus, A. clavatus and Fusarium oxysporum was 15.63 and 31.25 ?g /mL respectively, whereas, Humicola grisea showed MIC at 150 ?g/mL level. Cloning and sequence analysis of ketoacyl synthase gene revealed similarity to the type II polyketide synthase gene of Streptomyces species. The results showed that the antimicrobial potential of ERIAS-10 isolate could be suitable for pharmaceutical applications.

Keywords : Streptomyces roseoverticillatus, Antimicrobial activity, Minimum inhibitory concentration, Type II polyketide synthase.