Biosynthesis and Characterization of Gold Nanoparticles Using Zooglea ramigera and Assessment of Its Antibacterial Property

In the present study, synthesis of gold nanoparticles with bacterium Zooglea ramigera was reported. The biosynthesized gold nanoparticles were spherical in shape of the size range of 4–16 nm (by transmission electron microscopy). X-ray diffraction and specific area electron diffraction analysis revealed that the biosynthesized gold nanoparticles were in a face centered cubic (fcc) crystalline phase with the crystalline size of 19 nm. It was observed that the size of gold nanoparticles was varied with the pH of the solution. The biosynthesized gold nanoparticles were investigated for its antibacterial activity. The minimum inhibition concentration and minimum bactericidal concentration methods were used for studying antibacterial property. Gold nanoparticles showed excellent antibacterial activity against Gram-positive Staphylococcus aureus, Streptococcus pyogenes and Gram-negative Pseudomonas aeruginosa, Escherichia coli bacterial pathogens. The gold nanoparticles showed anti-tuberculosis impact in investigation against Mycobacterium tuberculosis H37RV. A hypothesis for antibacterial action of gold nanoparticles was also explained.