Investigation of Desulfurization Activity, Reusability, and Viability of Magnetite Coated Bacterial Cells.

BACKGROUND

Magnetic separation using magnetic nanoparticles can be used as a simple method to isolate desulfurizing bacteria from a biphasic oil/water system.

OBJECTIVES

Magnetite nanoparticles were applied to coat the surface of IGTS8 and Rhodococcus erythropolis FMF desulfurizing bacterial cells, and the viability and reusability of magnetite-coated bacteria evaluated by using various methods.

MATERIAL AND METHODS

Magnetite nanoparticles were synthesized through a reverse co-precipitation method. Glycine was added during and after the synthesis of magnetite nanoparticles to modify their surface and to stabilize the dispersion of the nanoparticles. The glycine-modified magnetite nanoparticles were immobilized on the surface of both oil-desulfurizing bacterial strains. Reusability of magnetite-coated bacterial cells was evaluated via assessing the desulfurization activity of bacteria via spectrophotometry using Gibb's assay, after the separation of bacterial cells from 96h-cultures with the application of external magnetic field. In addition, CFU and fluorescence imaging were used to investigate the viability of magnetite-coated and free bacterial cells.

RESULTS

TEM micrographs showed that magnetite nanoparticles have the size approximately 5.35±1.13 nm. Reusability results showed that both magnetite-coated bacterial strains maintain their activity even after 5 × 96h-cycles. The viability results revealed glycine-modified magnetite nanoparticles did not negatively affect the viability of two bacterial strains IGTS8 and FMF.

CONCLUSIONS

In conclusion, the glycine-modified magnetite nanoparticles have great capacity for immobilization and separation of desulfurizing bacteria from suspension.