5269
Hoda Abd Elrazek Kabary Bekhwagy
Studies on Biosynthesis of Magnetic Nanoparticles for Environmental Application
Magnetic, magnetosomes, Biosynthesis
Magnetotactic bacteria (MTB) are distributed worldwide, they having been found on all continents, they are ubiquitous in sediments of freshwater, brackish, marine, and hypersaline habitats as well as in chemically stratified water columns of these environments. In this work, we study the production of magnetite nanoparticles by bacterial cells internally (biosynthetic manners), and the probable application magnetosomes after being extracted from the bacterial cells for different environmental applications. The study concerned with the characterization of some efficient magnetotactic bacterial strains (MTBs) that were isolated from different iron contaminated sites. A total of 21 MTBs cultures were from sewage sludge specimen (8 isolates), iron-contaminated agricultural soil (10 isolates) and (3 isolates) from water wells. TEM analysis revealed that these bacterial isolates contained numerous mineral crystals similar to magnetosomes. From the previous successive purification steps only one isolate showed the best iron uptake as the iron concentration was completely consumed from the medium during the growth period and the resulted cellular biomass productivity was the highest value (OD600: 0.229). Based on their morphological and microscopy characteristics as well as16S rRNA gene sequence analysis, a new strain of Pseudomonas aeruginosa named KT962901.1 according to NCBI GenBank database. Optimization of the growth and iron uptake cultural conditions for P. aeruginosa cells as indicator for magnetosomes efficient production and biosynthesis, which shows that the bacterium is facultative anaerobic neutrophilic type. Extraction and purification of the magnetosomes by different methods (chemical and physical) and testing the purification efficiency by TEM images. Characterization of the purified magnetosomes by TEM, SEM, VSM, FTIR. Application of P. aeruginosa growing culture with included internal magnetosomes in salinity and divalent heavy metal removal for both Cd and Pb metals.
2017
Ph.d
Ain Shams
Science