Community structure of highly efficient phenol degrading bacteria and phenol metabolites

By using activated sludge from the anaerobic tank of a coking plant, a highly efficient phenol-degrading bacterial (PDB) community was successfully obtained through separation and domestication, and its effect on microbial degradation of phenol was investigated. The results showed that the degradation effect of PDB community on phenol was affected by the substrate concentration. The degradation rate reached 100% when the phenol concentration was lower than 700 mg/L. However, when the concentration of phenol increased to 1 300 mg/L, the degradation rate decreased to 41.6%. When the concentration of phenol exceeded 1 700 mg/L, the PDB community could basically unable to grow. High-throughput sequencing revealed that the species richness within the PDB community was high. Proteobacteria, Firmicutes, and Bacteroidota were dominant phyla, while Serratia sp., Bacillus sp., and Muribaculaceae sp. were core dominant genera of PDB. Metabolites analyzed by gas chromatography-mass spectrometry (GC-MS) revealed that the pathway for phenol degradation by PDB community was through ortho-cleavage, resulting in acidic intermediate products that subsequently decomposed into chain-like small molecular substances.