Research On The Evaluation Of Biodegradation Of Diesel And The Synergic Effect Between The Microorganisms

For the serious petroleum pollutant, the biodegradation technology was used more widely for its low cost, in-situ degradation and no pollution products. During the biodegradation of environmental pollutants, the determination of concentration and distribution of the pollutants is most important for the evaluation of the microorganism's biodegradability, to clarify the mechanism of biodegradation and to evaluate the biodegradation efficiency. In addition, the most important technological problem is that the biodegradability of the pollutants of microorganisms. So isolating and cultivating the microorganisms with high biodegradability are always the important and hot spots in the field of biodegradation of the persistent pollutants. In this work, a bacteria strain TT-b1 and a fungi strain TT-f2 were collected from contaminated sites, and the waste water which was polluted by diesel was biodegraded by the two kinds of microorganisms. Biodegradation of diesel was evaluated with gas chromatography and UV spectrophotometry. The experimental conditions have been optimized. Under the optimal conditions the synergic effect of biodegradation of diesel between the two kinds of microorganisms was investigated. The results are as follow: 1. The biodegradation of diesel were evaluated by gas chromatography and UV spectrophotometry. It is shown that the combination of the two simple analytical techniques remedies the shortage of the single one, and that the combination is successfully used to monitor the biodegradation efficiency of diesel and its primary components, and to evaluate separately the degradation of linear alkanes and aromatic hydrocarbons components. 2. The bulk culture conditions for the biodegradation of diesel by mixed bacteria were investigated. According to the growth curve, the mixed bacteria grow fast, and rapidly enter the logarithmic growth phase. After 10 hours, it's entered the balance growth phase. The optimal condition was explored: cultivated temperature 30℃, initial pH value 7.0 and the percentage of diesel concentration 1%. 3. The bacteria strain TT-b1 can degrade considerably n-octadecane, but can not effectively degrade diesel oil, because its growth is inhibited by aromatic hydrocarbons in diesel oil. The fungi strain TT-f2 is observed to be able to degrade diesel oil to a moderate extent. When the two strains are used simultaneously, a significant synergistic effect between them resulted in almost complete degradation of diesel oil. The observed synergistic effect is closely related to the aromatics-degrading ability of TT-f2, which favored the growth of TT-b1 and promoted the bioavailability of diesel oil.