Study On Degradation Characteristics Of Crude Oil And Toluene By Environmental Pollution Degrading Bacterium TG-1

Crude oil leakage and the problem of crude oil pollution in saline soil are becoming more and more serious.Microbial activity is inhibited under high-concentration crude oil and high-salt conditions,and it is difficult to apply bioremediation technology widely.After continuous enrichment and cultivation,the crude oil-degrading bacteria were separated,and a crude oil-degrading bacterium TG-1 was isolated,which was identified as Rhodococcus;the strain can grow with alkanes and benzene series as the sole carbon source;cultivated in inorganic salts The degradation rate of 6%mass concentration crude oil in the base is as high as 95.6%in7d,and the degradation rates of linear paraffins,pristane and phytan are all above 90%;in 1%-6%(10-60g/L)salt At the concentration,the degradation rate of crude oil is more than 65%;the degradation rate of crude oil is 79.3%and 60.7%for 15d crude oil salinized soil with salt concentration of 3%and 5%,respectively.The strain TG-1shows good salt tolerance and high efficiency of crude oil degradation,it has the potential to repair crude oil contaminated saline soil.In order to further explore the genes with degradation potential in TG-1,genome-wide analysis was carried out.It was found that tg-1 has a complete and single toluene degradation pathway.Subsequent experiments show that the toluene degradation efficiency of TG-1 is low,but Fe³⁺can greatly improve the toluene degradation efficiency of TG-1.At the concentration of 1mg/L,the degradation rate of TG-1 toluene increased the most by Fe³⁺(at 16 h,the degradation rate of toluene increased from 61.9%to 87.2%).A total of 345differentially expressed genes(DEGs)were detected by transcriptome analysis,including 213 up-regulated genes and 132 down-regulated genes.KEGG enrichment analysis showed that there were significant differences in the expression of toluene degradation genes.Then,fluorescence quantitative PCR confirmed that Fe³⁺had timeliness in promoting toluene degradation genes.This explains the promotion mechanism of Fe³⁺on toluene degradation,which will provide reference value for the subsequent bioremediation application of strain TG-1.