16S rRNA Gene-Based Detection of Tetrachloroethene-DechlorinatingDesulfuromonasandDehalococcoidesSpecies

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Abstract
Members of the generaDesulfuromonasandDehalococcoidesreductively dechlorinate tetrachloroethene (PCE) and trichloroethene. Two primer pairs specific to hypervariable regions of the 16S rRNA genes of theDehalococcoidesgroup (comprisingDehalococcoides ethenogenesandDehalococcoidessp. strain FL2) and the acetate-oxidizing, PCE-dechlorinatingDesulfuromonasgroup (comprisingDesulfuromonassp. strain BB1 andDesulfuromonas chloroethenica) were designed. The detection threshold of a nested PCR approach using universal bacterial primers followed by a second PCR with theDesulfuromonasdechlorinator-targeted primer pair was 1 × 103BB1 cells added per gram (wet weight) of sandy aquifer material. Total community DNA isolated from sediments of three Michigan rivers and six different chloroethene-contaminated aquifer samples was used as template in nested PCR. All river sediment samples yielded positive signals with the BB1- and theDehalococcoides-targeted primers. One chloroethene-contaminated aquifer tested positive with theDehalococcoides-targeted primers, and another contaminated aquifer tested positive with theDesulfuromonasdechlorinator-targeted primer pair. Restriction fragment analysis of the amplicons could discriminate strain BB1 from other knownDesulfuromonasspecies. Microcosm studies confirmed the presence of PCE-dechlorinating, acetate-oxidizingDesulfuromonasand hydrogenotrophicDehalococcoidesspecies in samples yielding positive PCR signals with the specific primers.