Characterization and Performance of Lactate-Feeding Consortia for Reductive Dechlorination of Trichloroethene.

Jiangwei Li,Shijie Bai,Xiaoyong Yang,Xu Liao,Anyi Hu,Qian Sun,Chang-Ping Yu

doi:10.3390/microorganisms9040751

Abstract

Understanding the underlying mechanism that drives the microbial community mediated by substrates is crucial to enhance the biostimulation in trichloroethene (TCE)-contaminated sites. Here, we investigated the performance of stable TCE-dechlorinating consortia by monitoring the variations in TCE-related metabolites and explored their underlying assembly mechanisms using 16S rDNA amplicon sequencing and bioinformatics analyses. The monitoring results indicated that three stable TCE-dechlorinating consortia were successfully enriched by lactate-containing anaerobic media. The statistical analysis results demonstrated that the microbial communities of the enrichment cultures changed along with time and were distinguished by their sample sources. The deterministic and stochastic processes were simultaneously responsible for shaping the TCE-dechlorinating community assembly. The indicator patterns shifted with the exhaustion of the carbon source and the pollutants, and the tceA-carrying Dehalococcoides, as an indicator for the final stage samples, responded positively to TCE removal during the incubation period. Pseudomonas, Desulforhabdus, Desulfovibrio and Methanofollis were identified as keystone populations in the TCE-dechlorinating process by co-occurrence network analysis. The results of this study indicate that lactate can be an effective substrate for stimulated bioremediation of TCE-contaminated sites, and the reduction of the stochastic forces or enhancement of the deterministic interventions may promote more effective biostimulation.

Highlights

Introduction published maps and institutional affilChloroethenes, such as trichloroethene (TCE), are halogenated aliphatic organic compounds that have been widely used as ingredients in industrial cleaning solutions and as “universal” degreasing agents due to their unique properties and solvent effects [1]
Due to its improper usage and indiscriminate disposal, TCE has been frequently detected with its concentration above 10 parts per billion [2], and has severely accumulated in certain anaerobic subsurface environments [3] and is often emitted into the atmosphere in vapor form, stripped either from groundwater or wastewater treatment plants (WWTPs) [4,5], which poses a serious risk to human health and can result in the generation of vinyl chloride (VC), a known human carcinogen [6], via natural or induced reduction processes [1,7]
On transferring the samples to a fresh medium, TCE dechlorination to cDCE and tDCE was evident in each microcosm, and with this transformation completed in 28 days and 41 days in the LCS

Summary

Introduction

Chloroethenes, such as trichloroethene (TCE), are halogenated aliphatic organic compounds that have been widely used as ingredients in industrial cleaning solutions and as “universal” degreasing agents due to their unique properties and solvent effects [1]. Due to the persistent nature of TCE in the environment, the development of effective and economical methods for its remediation has become a prime concern for researchers, and various physical and chemical methods have been developed and applied iations. Due to its improper usage and indiscriminate disposal, TCE has been frequently detected with its concentration above 10 parts per billion [2], and has severely accumulated in certain anaerobic subsurface environments [3] and is often emitted into the atmosphere in vapor form, stripped either from groundwater or wastewater treatment plants (WWTPs) [4,5], which poses a serious risk to human health and can result in the generation of vinyl chloride (VC), a known human carcinogen [6], via natural or induced reduction processes [1,7].

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