CENSUS – Chlorinated Propanes

Detect and quantify bacteria responsible for biodegradation of chlorinated propanes

Chlorinated propanes like 1,2,3-trichloropropane (TCP) and 1,2-dichloropropane (DCP) were used as industrial solvents and are still used as intermediates in the synthesis of other chlorinated chemicals including epichlorohydrin, carbon tetrachloride, and tetrachloroethene.  DCP was once commonly used as a soil fumigant for root-parasitic nematodes and insecticide for stored grain.

Under anaerobic conditions, some Dehalococcoides and Dehalogenimonas strains are capable of utilizing chlorinated propanes as growth supporting electron acceptors.  In Dehalococcoides strains and Dehalogenimonas spp., DCP undergoes dichloroelimination mediated by a dichloropropane dehalogenase to form propene (Ritalahti and Löffler 2004).  Dehalogenimonas isolated characterized to date appear to specialize in the dichlorelimination of a variety of chlorinated alkanes including TCP and DCP.  Reductive dechlorination of TCP produces an unstable intermediate (allyl chloride) which can by hydrolyzed to form allyl alcohol or undergo reactions with sulfide-reducing agents for form allyl sulfides (Yan et al. 2009).

CENSUS Targets for Chlorinated Propanes

Target

MI Code

      Relevance / Data Interpretation

 

Dehalogenimonas

               DHG Dehalogenimonas is a recently described bacterial genus of the phylum Chloroflexi which also includes the well-known chloroethene-respiring Dehalococcoides spp.  The Dehalogenimonas isolates characterized to date utilize a variety of vicinally chlorinated alkanes including chlorinated propanes (1,2,3-TCP and 1,2-DCP) and chlorinated ethanes (1,1,2,2-TeCA, 1,1,2-TCA, and 1,2-DCA).
 Dehalococcoides

 

DHC

 

While the range of compounds utilized varies by strain, some Dehalococcoides strains are capable of reductive dechlorination of DCP to propene.
 

Dichloropropane dehalogenase

 

 

1,2 DCP

 

 

Functional gene encoding the enzyme responsible for dechlorination of 1,2-DCP

 

 

Ritalahti KM, Löffler FE (2004) Populations Implicated in Anaerobic Reductive Dechlorination of 1,2-Dichloropropane in Highly Enriched Bacterial Communities. Applied and Environmental Microbiology 70 (7):4088-4095. doi:10.1128/aem.70.7.4088-4095.2004.

Yan J, Rash BA, Rainey FA, Moe WM (2009) Isolation of novel bacteria within the Chloroflexi capable of reductive dechlorination of 1,2,3-trichloropropane. Environmental Microbiology 11 (4):833-843. doi:10.1111/j.1462-2920.2008.01804.