Md. Amdadul Huq, Shahina Akter
The present study highlights the biological synthesis of AgNPs using Sphingobium sp. MAH- 11 and also their antibacterial mechanisms against drug resistant pathogenic microorganisms. The nanoparticle synthesis method used in this study was reliable, facile, rapid, cost effective and ecofriendly. The AgNPs exhibited highest absorbance at 423 nm. The TEM image revealed spherical shape of AgNPs and the size of synthesized silver nanoparticles was 7 to 22 nm. The SAED pattern and XRD spectrum revealed the crystalline structure of AgNPs. The results of FTIR analysis revealed the functional groups responsible for the reduction of silver ion to metal nanoparticles. The biosynthesized AgNPs showed strong anti-microbial activity against drug resistant pathogenic microorganisms. Moreover, E. coli and S. aureus were used to explore the antibacterial mechanisms of biosynthesized AgNPs. Minimal inhibitory concentrations (MICs) of E. coli and S. aureus were 6.25 μg/mL and 50 μg/mL, respectively and the minimum bactericidal concentrations (MBCs) of E. coli and S. aureus were 25 μg/mL and 100 μg/mL, respectively. Results indicated that the AgNPs caused morphological alterations and damaged the membrane integrity of strains E. coli and S. aureus. The AgNPs synthesized by Sphingobium sp. MAH-11 may serve as a potent antimicrobial agent for many therapeutic applications