| Lubricating oil is widely used in industrial and agricultural production. Due to theblocked recycle path, the immature recycle technology and the high recycle cost, therecycle utilization rate of lubricating oil is at low level. At the same time, theunreasonable production process and external factors such as improper operation, leadto a large number of lubricating oil pouring into the environment. This non-renewableoil contains refractory components, such as naphthene, aromatic hydrocarbons andheavy metals. It will lead to a deterioration of environment if this pollution spread in thesoil and water without manage. Physicochemical method always used in the treatmentof the waste lubricating oil pollution. Although this method can achieve success in ashort time, it will cause serious secondary pollution. Bioremediation can completelydigest the toxic pollutions by the function of microorganisms. As the core ofbioremediation technology, the development of efficient degradation bacteria is aresearch hotspot.The purpose of this experiment is to screen several efficient strains from the soilwith independent intellectual property rights. Waste oil and oil contaminated soil are theseparation source of our experiment. First we make a pretreatment to the waste oilcontaminanted oil, and then isolated51strains from this two kind of separation sourcewith traditional microbial purification technology. Then we choosed15lubricating oildegradation bacteria strains by use the24cavities experiment. After that we selected6strains with high efficient degradation by shaking flask experiment. And lipasedetection. And finally we studied the biodegradation ability of these strains. This studyfound out that the6selected strains had efficent oil resistance properties, and they coulddegrade with lube as the sole carbon source. The conclution is as follows:1) Waste lubricating oil and l soil contaminated by ubricating oil for a long timewere both a ideal source for the effective petroleum hydrocarbon degradation strains;2) The24cavities experiment take the auxocyte and static cells culture liqiud asinoculum to qualitative evaluate the biodegradation ability of the bacteria. We hadscreend15strains by using this method. The oil vatiations in cavities of lube can fit thecell concentration in the substrates;3)We screend6high lube biodegradation strains with shake flask test andsupplyment of lipase test. Two of the six strains were detected had a low lipase level, but the degradation abilities of this two strains had been proved by a series of shakeflask experiment. Basing on this result, we could make a conclution that the lipasedetection could only be a reference to determine the degradation ability of bacterias. Italso not means that bacteria with a low lipase should have a low degradation abilitu;4)In this study, we took both national standard and international popular method todetect lipsse of bacterias. The detection of lipase by sodium hydroxide titration showedthat the selected strains were all in the same low degree lipase. It was clear that thismethod was not suitable to this study. At the same time, ultraviolet spectrophotometryhad successfully tested the lipase vigor of cells;5) The biodegradation propertied test showed that the number six selected bacteriascould not be alive in the lube oil with a concentration of600mg/L, but it had a efficencedegradation ability when the concentration was below500mg/L. number4and5alsocould not be alive in lube of700mg/L. But they could well degrade lube when theconcentration was down. All the6strains could almost completly degrade the500mg/Llube in144hours, except number6strains. While this exception strain could degrade80%of the whole lube oil. |
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