Study On The Specific Proteins Of Methyl Tert-butyl Ether Degradation By Methylibium Petroleiphilum PM1 And The Novel Technology Of Bacteria-alga Mixed Culture

Methyl tert-Butyl Ether (MTBE) was added to gasoline to enhance its octane index. Their addition also improved the combustion efficiency and therefore decreased the emission of pollutants. But being highly soluble in water and recalcitrant to biodegradation, MTBE was a major pollutant of water in aquifers contaminated, and had become a widely concerned problem all over the world.Methylibium petroleiphilum PM1 (PM1) that might utilize MTBE as sole carbon and energy resources was used to biodegrade MTBE. In this research, we investigate the specific proteins in degradation of MTBE and the mixed culture of alga and bacteria in closed culture system was introduced for MTBE aerobic biodegradation.PM1 was incubated into culture medium with MTBE, TBA or acetone, respectively. Then the cells were harvested and the total cell proteins were extracted from the cells for SDS-PAGE electrophoresis. The protein diversity of cells after growth on MTBE and on TBA as carbon source was similar. However, they were different from that on acetone, the proteins involved in MTBE and TBA metabolism differ from them involved in metabolism at 28 KD, 42 KD and 66.2 KD. The band of 28 KD proteins was isolated for the following study. The target protein could be get by the following process: cut the difference protein, horizontal SDS-PAGE, dialysis, deposition by iced acetone, The two dimension electrophoresis showed that this method can obtain simplex protein. After the determination of peptide mass finger-printings, the isolated protein was similar to the conjugative transfer protein TraW.MTBE degradation by algae-bacteria mixed culture was evaluated in closed system, in which oxygen might be permanently supplied by the photosynthesis of Chlorella ellipsoidea which utilized the carbon dioxide produced from the complete mineralization of MTBE by bacteria in the closed system. The mixed culture of PM1 and C. ellipsoidea in the closed system was found to be favorable for MTBE degradation. At the time of 168 h, the PM1 degradation efficiency was about 60%, while mixture system of Chlorella ellipsoidea and PM1 was 100%. And the best proportion of PM1 and algae is 100:1.Cells of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea were co-immobilized in gel beads to degrade MTBE. The gel beads containing high concentration of cells could degrade MTBE effectively. The degradation efficiency of co-immobilized of PM1 and algae higher than the mixture of PM1 gel beads and algae gel beads. The efficiency of PM1 gel beads was the lowest.