ABSTRACT
To better understand the microbial oil removal enhancement process by a magnetic field, the effect of a static magnetic field (SMF) on the microscopic characteristics of highly efficient biodegradation oil-removing bacteria was studied. The Acinetobacter sp. B11 strain with a 53.6% oil removal rate was selected as the reference bacteria. The changes in the microscopic characteristics of Acinetobacter sp. B11 such as the cell surface morphology, cell permeability and cell activity of the bacteria were investigated. The results showed that low-intensity magnetic fields (15-35 mT) improved the ability of Acinetobacter sp. B11 to remove oil by 11.9% at 25 mT compared with that of bacteria with no magnetic field. Without destroying the cell membrane, the low-intensity magnetic fields increased the cell membrane permeability and improved the activity of superoxide dismutase (SOD), which effectively enhanced the oil degradation performance of the bacteria.
Subject(s)
Acinetobacter/growth & development , Magnetic Fields , Petroleum/analysis , Water Pollutants, Chemical/analysis , Water Purification/methods , Acinetobacter/metabolism , Biodegradation, Environmental , Cell Membrane Permeability , Models, TheoreticalABSTRACT
The patented technology of a High Gradient Magnetic Separation (HGMS)-Ultraviolet (UV) composite process was used to treat ballast water. Staphylococcus aureus (S. aureus) was selected as the reference bacteria. After treatment by the HGMS-UV process, the concentration of S. aureus on the log 10 scale was lower than 2 at different flow rates, S. aureus suffered the most serious damage, and K(+) leakage of the bacteria was 1.73mg/L higher than separate 60min UV irradiation (1.17mg/L) and HGMS (0.12mg/L) processes. These results demonstrated that the HGMS-UV composite process was an effective approach to treat ballast water. Further, the HGMS process had synergistic action on the subsequent UV irradiation process and accelerated cell membrane damage. Meanwhile, the results of superoxide dismutase (SOD) activities of bacteria and DNA band analyses indicated that the inactivation mechanisms were different for HGMS and UV irradiation.
