Structure of Toluene-degradation Anaerobic Denitrification Microbial Community in Coking Contaminated Soil

With a greater amount of attention paid to the pollution of the environment caused by coal processing, methods using soil microorganism repairing to improve coking contaminated soil becomes more and more significant. The biodegradation of toluene or benzoate and the nitrate-reducing process were analyzed in coking contaminated soil by the addition of toluene or benzoate as the sole carbon source as well as energy source in enrichment solution under nitrate-reducing, then the structural diversity of anaerobic denitrification microbial community of degradation toluene or benzoate was compared by high throughput sequencing. The molar ratio of toluene or benzoate to nitrate was 1∶8.7 or 1∶5.9, respectively, a reasonable approximation of the theoretical stoichiometric ratios. After 120 days of enrichment, the main bacteria in the coking soil is Proteobacteria, and the advantage phylum of phenol degradation in soil enrichment under the condition of nitrate reduction is Firmicutes, while for benzoate it is Proteobacteria. α-, and γ-proteobacteria, Bacilli is the dominant class in toluene-degrading bacteria, and the dominant class in the degradation of benzoate is β-proteobacteria. The results show that Exiguobacterium is the predominant genus of toluene-degrading bacteria, while Azoarcus is the dominant species in benzoate.