Degradation Mechanism of 4-Chlorobiphenyl by Consortium of Pseudomonas sp. Strain CB-3 and Comamonas sp. Strain CD-2

Curr Microbiol. 2020 Jan;77(1):15-23. doi: 10.1007/s00284-019-01791-9. Epub 2019 Oct 24.

Abstract

Polychlorinated biphenyls (PCBs) are types of lasting environmental pollutants which are widely used in various industries. 4-chlorobiphenyl (4CBP) is a PCB which is harmful to the environment as well as humans. Two strains, CB-3 and CD-2, were isolated from the polluted soil of a chemical factory and could completely degrade 50 mg/L 4CBP within 12 h by co-culture. The consortium comprising strains CB-3 and CD-2 was effective in the degradation of 4CBP. 4CBP was degraded initially by strain CB-3 to accumulate 4-chlorobenzoate (4CBA) and further oxidised by strain CD-2. Based on 16S rRNA gene sequence analysis and phenotypic typing, strain CB-3 and strain CD-2 were identified as Pseudomonas sp. and Comamonas sp., respectively. The substrate spectra experiment showed that strain CB-3 could degrade PCBs with no more than three chlorine atoms. A gene cluster of biphenyl metabolism was found in the genome of strain CB-3. Besides, a dechlorination gene cluster and a gene cluster of protocatechuate (PCA) metabolic were found in the genome of strain CD-2. These gene clusters are supposed to be involved in 4CBP degradation. The ability of strains CB-3 and CD-2 to degrade 4CBP in soil was assessed by soil experiment, and 4CBP at the initial concentration of 10 mg/kg was 80.5% removed within 15 days.

MeSH terms

  • Biodegradation, Environmental
  • Biphenyl Compounds / metabolism*
  • Chlorobenzoates / metabolism
  • Comamonas / metabolism
  • Multigene Family / genetics
  • Pseudomonas / metabolism
  • RNA, Ribosomal, 16S / genetics
  • Temperature

Substances

  • Biphenyl Compounds
  • Chlorobenzoates
  • RNA, Ribosomal, 16S
  • 4-chlorobenzoic acid
  • 4-chlorobiphenyl