Degradating Characteristics Of Petroleum-degrading Bacteria From Estuarine Area In Northern China

Petroleum degrading bacteria is a category of microorganism which is capable of decomposing and mineralizing petroleum hydrocarbons, thus plays an important role in the restoration of petroleum pollution. Petroleum degrading bacteria is widespread in nature. Many factors can influence the removal rate of the strains, such as the type and composition of petroleum hydrocarbons,the physical state and Concentration of oil, temperature, pH, DO and the nutrients.All the above factors decide the removal results together.There are many kinds of petroleum-degrading bacteria, including 70 Sp of 200 species.The species differ, the tolerance of temperature, pH and salinity differ. The tolerance of bacteria decides its application. In the estuarine area of Northern China, there are great significant in filtering bacterias of better tolerance on removing oil.Liaohe River coastal wetlands located in the south of Liaoning Province and in the north of Bohai Sea, belong to warm temperate monsoon climate. There are large temperature changes during the year, at 8.6℃-9.4℃Average. Liaohe River coastal wetlands Near the Liaohe oil field, oil spill pollutions are serious, while Water pollution accidents occur every year for the Terminal CAO. The pollutions from water and land Have led to some serious environmental consequences, and threat the ecological balance gravely. Water pollution problems have become more prominent, and have become a social issue of concern.Firstly, ten diesel oil degradable strains were obtained from oil-contaminated soil by using screening cultural medium method which using 0# diesel oil as the sole carbon source. The degradation ratio of diesel oil by the strains was tested by using ultraviolet spectrometry method. Two of the strains showed potential for further utilization with a degradation ratio of diesel oil by 60% above incubating for 8 days. Based on the morphological,physiological and biochemical test results, the strains were identified as Staphylococcus pasteuri and Stenotrophomonas maltophili.Secondly, the tolerance of the strains were studied and the proper conditions were searched. The results showed that the two strains have fine tolerance of temperature, pH and salinity, and could grow well in the estuarine area in northern China. Using the techniques of GC-MS, the range of carbon reduction was analyzed, the results showed the strains could reduce Alkanes from C8 to C26 well.Furthermore, this paper also studied the joint action of the two strains.The result showed there were better consequent than that in strain alone, the removal rates could be above 70%.These could provide important theoretical support in the actual application of the two strains.