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Potential of luminescent bacteria in production of metal nanoparticles has not been well evaluated up until now. These bacteria contain lux operon which is included of reductase enzymes, by increasing bacterial cell density, the expression of aldehyde synthetic enzymes elevate and enhance the yields of nanoparticles synthesis. Therefore, in this study extracellular synthesis of gold nanoparticles using natural occurring luminescent bacteria, VLA, VLB, VLC and genetically engineered luminescent bacteria, Pseudomonas putida KT2440 and Pseudomonas fluorescence OS8 has been successfully conducted. Nanoparticles were characterized and their antibacterial activity evaluated using microtiter plates at different concentrations against some hospital pathogenic bacteria .Biosynthetic gold nanoparticles produced in this study had maximum absorption at the ranges of 500 to 550 nanometer wavelengths. TEM images showed particle sizes between 10 to 50 nanometers and confirmed the success of purification process. The NPs were spherical and the FTIR analysis showed the existence of biomolecules on surface of purified nanoparticles that could be most probably related to reductase enzymes that is stabilized on nanoparticles surfaces. Further investigation on antibacterial properties of these novel nanoparticles which coated by reductase enzymes showed that any increase or decrease in antibacterial activity is depended on nanoparticles concentration. |
