Antibacterial activity of Microbispora rosea subsp. rosea SL3- 2-R-1 grown on different media and solidifying agents

The aim of this study was to examine the effect of different media and solidifying agents as growth media of a rare thermophilic actinobacterium, strain Microbispora rosea subsp. rosea SL3-2-R-1, on its antibacterial activity. To investigate the antibacterial potential, the strain was grown on four media, e.g., International Streptomyces Project (ISP) 1, ISP 2, ISP 3, and Bennett's medium, solidified with agar and gellan gum, at 45 °C for 21-days. The antibacterial activity screening was performed using the agar plug diffusion method against four bacterial test strains (S. aureus, B. subtilis, K. rhizophila, and E. coli) grown on Mueller-Hinton agar, incubated at 30 °C for 17 h. The antibacterial activity was observed on strain grown on ISP 1 gellan gum, ISP 2 gellan gum, ISP 3 agar, ISP 3 gellan gum, and Bennett's agar against B. subtilis. The strain grown on ISP 1 gellan gum, ISP 3 agar, and ISP 3 gellan gum inhibited the growth of K. rhizophila, while on ISP 1, gellan gum and ISP 3 agar were positive against S. aureus. However, on all media, the strain showed no inhibition against E. coli.