ENRICHMENT OF MICROORGANISMS ABLE TO TRANSFORM 1,2,3-TRICHLOROBENZENE FROM PRISTINE MARINE SUBSURFACE SEDIMENTS

In this study, 1,2,3-trichlorobenzene was transformed to 1,3-dichlorobenzene in cultures inoculated with pristine sediments (4 meters below seafloor) from the Chilean continental margin. Dehalogenating microorganisms were enriched by sequential transfers and characterized. 16S rRNA gene amplicon sequencing of microbial communities in sediment cultures and transfers indicated that bacteria affiliated with the family Peptococcaceae, phylum Firmicutes, were involved in the transformation of 1,2,3-trichlorobenzene. Biochemical inhibition studies suggested dehalogenation was catalysed by corrinoid-containing enzymes as described for most respiratory reductive dehalogenases. Biochemical activity assays and cultivation indicated the potential for debromination by the microorganisms in transferred sediment cultures. Altogether, this study contributes to the understanding of the ecological role of organohalide-respiration as respiratory process in marine sediments and the bacteria involved.