Isolation And Identification Of Efficient Oil-degrading Bacteria And Their Application In Bioremediation

Due to the seeps,emissions and anthropogenic activities such as spillages during transportation, oil pollution has been the most common sources of organic pollutants for the marine environment. Among the present disposal ways of oil pollution, microbiological restoration attracts people’s attention due to its economy, efficiency and no second contamination. It has important theoretical and practical value to seek out efficient marine oil-degrading bacteria and optimize its degradation conditions for marine oil bioremediation.Staying in an open system, bioremediation of the beach is influenced by many factors, so it’s very important to imitate the beach environment and track the repair process.In this experiment,25oil-degrading bacteria strains were isolated from the beach near Dalian Bay.SW5-3、SQ4-2、SY4-2、SC5-1had a significant effect on crude oil removal within10days, the degradation rate were54.87%,38.42%,34.44%,31.42%respectively. Using Physiological and biochemical identification, electron microscopy and16S rDNA sequence analysis, strain SQ4-2was identified as Advenella kashmirensis, SW5-3was identified as Acinetobacter venetianus, SY4-2was identified as Achromobacter xylosoxidans, SC5-1was identified as Alcaligenes xylosoxidans subsp.xylosoxidans. This experiment gives the first report of Advenella kashmirensis. about its application in oil degradation We proved its degradation efficiency of crude oil, therefore, Advenella kashmirensis. has a great application potential in oil bioremediation.These four marine oil-degrading bacteria were selected to form bacterial consortium. The most efficient mixed strains were constructed by using these four strains with proportional combination.Its oil degradation rate increased to70.33%, nearly25%higher than the most efficient single bacterium, showing significant synergism in the bacterial consortium. Advenella kashmirensis enhanced oil degradation rate obviously., playing a crucial role in the bacterial consortium. Refractory components in crude oil can be degradated by adding co-substrates.The results showed that in the most efficient group, beef extract was used as co-substrate and the quality ratio with crude oil was1:4, the degradation rate was82.04%,12%higher than experimental group without co-substrates.A bioremediation simulation system was constructed to monitor oil degradation process and the sTableility of the flora within the system. Results showed that:after20days of bioremediation,98.26%of the crude oil on the surface has been removed, oil in the water was got rid of90.67%, the effect is remarkable.Oil pollution experienced a rapid degradation within12days, labile components of crude oil have been used up, degradation of refractory components still needs longer time. Oil-degrading bacteria joined in this study formed the dominant species in the open system.The entire process of bioremediation does not require new dosing.