Antibacterial activity of a thermophilic actinobacterium Streptomyces cellulosae SL2-2-R-9 on different growth media

Thermophilic Actinobacteria are known as potential producers of novel antimicrobial compounds. However, the optimum growth medium for antibacterial activity assessment of thermophilic Actinobacteria has rarely been reported. This study demonstrated the effects of nine different microbial growth media on antibacterial activity assessment of a thermophilic actinobacterium from the soil in Cisolok geysers, Sukabumi, West Java (Indonesia). The strain SL2-2-R-9 was identified as Streptomyces cellulosae based on 16S rRNA gene data (100% similarity). The antibacterial activity was examined by the agar plug diffusion method against five bacterial test strains. The result of antibacterial activity screening showed that SL2-2-R-9 grown on ISP 7 agar and Bennett's gellan gum inhibited the growth of Bacillus subtilis, Staphylococcus aureus, and Kocuria rhizophila. Strain grown on ISP 3 gellan gum inhibited the growth of B. subtilis andS. aureus, while on 301 agar and TSA, inhibited only K. rhizophila. Strain grown on ISP 6 agar and modified Bennett's gellan gum, inhibited onlyS. aureus. Strain grown on ISP 3 agar and SFM agar showed no inhibition zone against all tested bacteria. There was no inhibition observed against Gram-negative bacteria when the strain was grown on all media.