Screening Of Low Temperature Petroleum Hydrocarbon Degrading Bacteria And Bioremediation Of Petroleum Contaminated Soil

Petroleum is one of the indispensable energy resources in the production and life of human society.While it is exploited and utilized,it also leads to many environmental problems.In the exploitation and utilization of oil,leakage accidents often occur,which leads to the serious problem of soil pollution caused by oil.Microbial remediation technology is one of the most environmentally friendly and potential technologies for the treatment of oil-contaminated soil,which has attracted widespread attention.This study from kelamayi oil field near by oil pollution in soil for a long time,under the low temperature environment after enrichment,separation and purification are 5 strains with obvious strains colony characteristics,the screening of strains through the biodegradation of petroleum hydrocarbon compound sieve,preliminary screening of 5 bacteria strains were found on the degradation of petroleum hydrocarbons has a certain capacity,Name them XK15-1,XK15-2,XK15-3,XK15-4,and XK15-5.Through morphological,physiological and biochemical characteristics and 16 S r DNA sequence analysis,the five strains screened were identified to the species genus.Strain XK15-1 was Pseudomonas monteilii,strain XK15-2 was Stenotrophomonas pavanii,strain XK15-3 was Agrobacterium tumefaciens,strain XK15-3 was Agrobacterium tumefaciens.The strain XK15-4 was Dietzia maris,and the strain XK15-5 was Sphingomonas pseudosanguinis.The results showed that the degradation rates of XK15-1,XK15-2,XK15-3,XK15-4 and XK15-5 on petroleum hydrocarbons were 34.88%,31.77%,44.94%,15.34% and 39.70%,respectively.The degradation characteristics of three strains XK15-1,XK15-3 and XK15-5 with higher degradation rates were studied.The results showed that the optimal initial p H of XK15-1,XK15-3 and XK15-5 were all in neutral environment,the optimal inoculation amount was 15%,the optimal petroleum hydrocarbon concentration was 5 g/L,and the optimal salinity was 1%.The strains XK15-1,XK15-3 and XK15-5 were mixed,and the degradation characteristics of the mixed bacteria with higher degradation rate were studied.The degradation rates of the compound bacteria K3 and K4 were 53.89% and 55.62%,respectively,which were higher than that of the single strain.The degradation rates of the compound bacteria K1 and K2 were lower than that of the single strain.The optimal inoculation amount of the compound bacteria K3 and K4 was 12%,the optimal p H value was 7.0 and 7.5,and the optimal salinity was 2% and 1%,respectively.A pilot study on bioremediation of oil-contaminated soil was carried out by using the screened strains.The results showed that the degradation rates of petroleum hydrocarbons by XK15-1,XK15-3 and XK15-5 were 16.26%,22.13% and 19.20%,respectively.The degradation rates of the complex flora K3 and K4 were 26.40% and 28.53%.The obtained low temperature petroleum hydrocarbon degrading bacteria can be used as bioremediation strains of petroleum contaminated soil under low temperature environment,which provides a certain reference basis for the use of microbial remediation of petroleum contaminated soil under low temperature environment.