Title

Microbial Oxidation of 1,2-Dichloroethane under Anoxic Conditions with Nitrate as Electron Acceptor in Mixed and Pure Cultures

Publication Date

6-1-2006

Document Type

Article

Abstract

Many organisms have been found to readily oxidize the prevalent contaminant 1,2-dichloroethane (1,2-DCA) to CO2 under aerobic conditions. Some organisms have also been isolated that can reduce 1,2-DCA to ethene via dihaloelimination under anaerobic, fermentative conditions. However, none have been described that can metabolize 1,2-DCA under anoxic, nitrate-reducing conditions. In microcosms prepared from aquifer material and groundwater samples from a contaminated site in eastern Louisiana, USA, 1,2-DCA was observed to degrade with nitrate as the terminal electron acceptor. Nitrate-dependent enrichment cultures were developed from these microcosms that sustained rapid 1,2-DCA degradation rates of up to 500 μM day−1. This degradation was tightly coupled to complete reduction of nitrate via nitrite to nitrogen gas. A novel 1,2-DCA-degrading organism belonging to the Betaproteobacteria (affiliated with the genus Thauera) was isolated from this enrichment culture. However, degradation rates were much slower in cultures of the isolate than observed in the parent mixed culture. Complete mineralization of 1,2-DCA to CO2 was linked to cell growth and to nitrate reduction in both enrichment and isolated cultures. Monochloroacetate, a putative metabolite of 1,2-DCA degradation, could also be mineralized by these cultures.

Publication Title

FEMS Microbial Ecology

Volume

56

Issue

3

First Page

355

Last Page

364

DOI

10.1111/j.1574-6941.2006.00077.x

Version

pre-print, post-print with restrictions

This document is currently not available here.

Find in your library

Share

COinS