Study On Micro-mechanism Of Oil's Biodegradation By Soil Microorganisms

Currently biodegradation process of microorganism became the active realm of polluted environment research including metabolism, transformation, degradation. However, mechanism of oil's biodegradation by microorganism was still unknown because of the complex of three phase systems. Supported by Chinese National Natural Science Fund (40472129), we used n-Hexadecane and Nonadecan as main representative pollutants, and microorganisms taken from Shengli and Daqing oil fields, experiments were made in laboratory to analyze the characteristics and principle of oil's biodegradation. Using crude oil as sole carbon sources, 4 microorganisms with high capacity of oil's biodegradation were filtered and separated by contrastive methods from Shengli oil fields. At different initial concentrations of n-Hexadecane and Nonadecan, static cultivation and vibration with 150r/min proceeded 44 hours to analyze biodegradation in and out of microorganism's cell. Gas chromatography results showed that big differentia of bio-degradation rate existed in five microorganisms; the best condition of degradation at static cultivation was the initial pollutant concentration between 10 and 20 μg ?L?1, so was around 30 μg ?L?1 at vibration with 150r/min. GC-MS analysis showed that both palmitic acid and representative pollutants were found in and out of microorganism's cell. The appearance time of n-Hexadecane analyzed by GC were in 6.4min～6.5min, so was Nonadecan in 11.3min. The touch between n-Hexadecane and microorganism' s membrane was also observed by Laser Scanning Confocal Microscopy(LSCM) at 543nm lights for 120 seconds. Digital analysis results showed that the membrane was colored with red and concentration of n-Hexadecane absorbed in membrane was increased on an irregular serration. Concentration of n-Hexadecane from Z-axis scanning analysis was increased firstly, then decreased at low spectrum, the similar results to the process of layer' s scanning. N-Hexadecane's equation of reaction kinetics -dS/dt =6 ×e^-5S²-0.3051S+380.58 in membrane was made at 2 levels, and ascertained the constant of degradation velocity.