Screening and partial purification of antibacterial compounds from Streptomyces sp. strain RS2

Abstract

Streptomyces sp. RS2 was isolated from soil samples in Dong Pong village, KhonKaen province, Thailand. The active strain RS2 was identified as genus Streptomyces, and it was related to S. gelaticus NRRL B-2928T at 99.43% 16S rDNA similarity. It was screened for antifungal and antibacterial activities by dual culture and cross streak methods, respectively. The results showed that Streptomyces sp. RS2 exhibited anti-microbial activity against fungal and gram-positive and gram-negative bacteria. Therefore, it was cultured on ISP2 medium at 30°C for 7 days. After incubation, the culture medium was dried, and the mashed biomass was extracted with organic solvents as methanol (MeOH). The crude MeOH extract was purified by using a high performance liquid chromatography (HPLC) with diode-array detector (DAD). Additionally, the partial purified fractions were tested for antibacterial activity by agar well diffusion method. The results showed that 5 fractions showed antibacterial activity against S. aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922. The fraction number 3 and 4 exhibited the highest antibacterial activity, these fractions will be interested to purify and study in the function of the active compounds in the future.