Study On Construction Of High-Effective Microbiol Consortium For Degrading Petroleum And The Bioaugmentation On Bioremediation

Petroleum is a complex mixture of thousands of components like n-alkane, aromatics, asphaltenes and resins. The pollution produced in the process of oil exploitation, refining , transporting and waste oily water draining has become an important resource to soil contamination. Bioaugmentation technology is the main method in bioremeding petroleum pollution. Biodegradation of petroleum hydrocarbons is a complex process that depends on the nature and amount oil or hydrocarbons present. Individual microorganisms can metabolize only a limited range of hydrocarbon substrates, so how to degradate petroleum effectively and thoroughly is one of the problems we are going to solve. To employ high-effective microbiol consortium can maximize biodegradation, so we took the consortium we had constructed as the exotic microorganism to carry out bioaugmentation. And biosurfactant has been proved to play an important role in increasing petroleum degradation and has been applied broadly, we screened a bacterium that can product biosurfactant from the series of degrading bacteria we had gotten, which makes the bacterium have both the fuctions of degrading and biosurfactant-producting. We put it in the consortium to improve the degrading capability of the consortium. How to put so many bactetia with different fuctions together and make them get alone is an important problem. So we supposed to screen a series of microorganisms and construct a high-effective microbial consortium, including the biosurfactant-producing bacterium, so that different functions can be assembled and used in petroleum degradation. The study contents include :1. Screening of petroleum-degrading bacteria. Alkane, cycloparaffin and PAHs were used separately as the sole carbon resource to screen a series of degrading bacteria. We also studied the biomass during the degradation.2. High-effective bacteria were gotten by UV-induce mutation. Bacteria yw1 and yw2 were obtained from w1 and w2 by UV-induce mutation. Their reproducing ability, degradating ability and resistances to high-concentration oil have increased markedly.3. Screening of biosurfactant-producing bacterium and its nature. We Screened a biosurfactant-producing bacterium from the series of degrading bacteria and studied the nature of the biosurfactant-producing bacterium and the role it played in the petroleum degrading. This bacterium has good resistances to acidity, salt and temperature, and it can improve the degradating ability of the other bacteria when they mixed together.4. Construction of high-effective microbial consortium. 9 bacteria were selected by initial oil test. Their functions in the process of degrading petroleum were detected by GC-MS analysis and by which we construct some rational consortiums.5. Bioaugmentation with high-effective microbial consortium. One of the consortiums was used to bioremedy contaminated soil. We also studied the effect of different conditions on the bioremediation. The results show that During the process of 40-day bioremediation, bioaugmentation improved the degradation rate by 15.59% compared with that in nature condition. Microorganism will be more active with the increase of temperature, so does the degradation rate; adding nutrition and oxygen content will also be contributed to microorganism growth and in the end enhance the biodegradation.