Phylogenetic characterization of a mixed microbial community capable of degrading carbon tetrachloride

Two bacterial communities (NO92 and GBS) capable of degrading carbon tetrac hloride (CT) were enriched from in-house CT-contaminated water. These commu nities are able to degrade CT in the presence of toluene. To characterize t he community structure and diversity, one enrichment (NO92) was subjected t o 16S ribosomal RNA (rRNA) gene-based molecular analysis. The 16S rRNA gene s were amplified from the bulk genomic community DNA and. cloned into plasm id vectors. Unique 16S rRNA gene clones, i.e., phylotypes, were detected by four tetrameric restriction enzymes. Together, 123 16S rRNA gene clones we re obtained; thirty-one showed different restriction fragment length polymo rphism (RFLP) patterns. About 73% of the clones belong to two dominant RFLP patterns. Phylogenetic analysis based on the partial 16S rRNA gene sequenc es of 10 major phylotypes showed that all the phylotypes that were sequence d were affiliated with the high G+C Gram-positive bacteria. Whereas seven o f the phylotypes (similar to 80% of the clones) were closely related to Rho dococcus, the other three (similar to 5% of the clones) were related to Cur tobacterium. These results suggest that this CT-degrading community is dive rse but is predominated by closely related bacterial groups.