The Isolation And The Study Of The Degragation Character Of Petroleum Predominant Strains

With the development of petroleum industry, the pollution caused by the petroleum becomes more and more serious. This pollution problem endangers the health of mankind. Therefore, the people pay more and more attentions to this problem. In order to get rid of the petroleum from the environment, the scientists carry out a lot of scientific researches. Now they are still looking for the safe, economic and reliable techniques to solve this problem.This paper has shown up the reader in chapter one the following summed up informations: (1)about the constitutions, the sources, the patterns of migration, the transformation and distribution and the dangers of the oil in the environment; (2)almost all of the treating methods for oil in environment, especially, there is a more detailed information about the biodegradation methods of oil. Comparing these various treating methods, it is evendent that bio-method has more advantages.Six predominant strains for degradating oil have been isolated and differentiated. Experiments have been carried out to test the degrading abilities of the six strains.The results of the differentiation for the strains is that: SY1 belongs to Microbacterium, SY2 belongs to Nocardia, SY3 and SY5 belong to Pseudomonas, SY4 and SY6 belong to Bacillus. The results of the experimental tests show that NH4Cl and K2HPO4, KH2PO4 are the most available nutrents to our isolates when they are degrading oils. The most suitable experinment condition is: temperature being 30 C, initial pH being 7-8, the shaking rate of the culture flasks is 180 r/min, the concentration of NaCl is 1 %. The biodegradation results have shown that our 6 isolates have the effective degradation capability to crude oil; within 6 days the transforing rate of oil by each single strain is more than 60%. And the biodegradation reaction of oil by our isolates proceeds according to first kinetics. In the degradation system, emulsification often enmerges automatically, so the bio-surfactant must be produced and the degradation of crude oil must be enhanced. The inorganic ions and co-substrates can influence thebiodegradation of crude oil. Generally, the results also show that our 6 single strains are more effective than the mixture of them. The biodegradation mechanism of petroleum still need further to research deeply in order that the strains can be applied in practical environmental engineering.