一株石油烃降解菌对原油的降解特性

On the bacteria-degrading features of a strain of crude oil E-2

从山东胜利油田沿海滩涂石油污染水体中分离得到1株以原油为唯一碳源的降解菌E-2。通过对原油降解率的测定,发现菌株E-2对石油具有较强的降解能力。在条件初步优化下培养5 d,其对原油的降解率在扣除自然降解部分后达到50.51%。E-2最适宜生长条件为:温度37℃,pH=7.5。当NaCl质量浓度为0～5 g·L^(-1),原油质量分数为0.75%～1.5%时菌株E-2处于最佳生长状态。通过GC-MS分析,菌株E-2对原油中链烃C34～C38的部分降解最显著,对链烃C26～C33也有一定的降解作用,表明E-2对长链烃类的降解具有明显的优势。菌株E-2与优势菌株HB-1按1:1组成混合菌液,两种菌株仍能各自显著降解链烃碳源,同时对C16～C30的降解明显增强,反映了两菌对这一段碳链的协同降解效果。HB-1与E-2按1:1混合,石油降解率提高到63.62%(单独HB-1菌株石油降解率为54.62%);HB-1与E-2按1:3混合,其降解率为80.60%;HB-1与E-2按3:1混合,降解率为81.83%。

The present article is aimed at introducing our study on the bacteria-degrading features of a sample strain of Crude Oil E - 2 obtained from the oil-contaminated water from Shengli Oil Field, Shandong, with the crude oil as a sole carbon source. As is known, with the crude oil extensive exploration, transportation and application all over the world, the problem of crude oil pollution for the water body has been attracted wider and wider attention. Due to its great advantages, bioremediation of the crude oil condemnation has become a hot topic among the specialists in this field in recent years. Enough research results show that strain E - 2 enjoys a strong oil-degrading capability for its pollution-degrading rate. To be exact, its oil degrading rate proves to be able to reach 50.51% when natural degradation was included under incubation for 5 days. We have also found that the optimal growth condition of strain E - 2 tends to be at the temperature of 37 ~C and pH value of 7.5 as is derived from our testing. The said E - 2 strain was found growing in an optimistic condition with the salt concentration and the volume fraction of the oil being 0 - 5 g· L^- 1, 0.75 % - 1.5 % respectively. The results of our GC - MS analysis indicate that the degradation of aliphatic hydrocarbon of C34 - C38 in the crude oil by strain E - 2 is highly remarkable. In addition, thestrain has also proved to affect obviously on the aliphatic hydrocarbon of C26 - C33. This has in turn shown the remarkable superiority of strain E - 2 in the long chain hydrocarbon degradation. In addition, strain E - 2 and HB - 1 can also help to degrade the respective hydrocarbon chains when they are formed into a bacteria mix （ 1 ： 1 ）. Furthermore, the degradation capability of hydrocarbon of C16 - C30 has been found greatly improved by the bacteria mix （ 1 ： 1 ）, which suggests that the mix （ 1 ： 1 ） has a concerted degradation effect when the ratio of the mixed bacteria solution is 1 ： 1. Thus, the crude oil degradation efficiency can be raised to 63.62% as 1：1 mixed bacteria solution, though it was only 54.62% by using only strain HB - 1. However, when the bacteria mix was used with HB - 1 and E - 2 in a ratio of 1：3, the degradation rate would be found going up to 80.60% . Thus, if the bacteria of the two strains were mixed in a ratio of 3：1, the degradation rate would go up to 81.83% .