Microbial ecology of chlorinated solvent biodegradation

Abstract

This study focused on the microbial ecology of tetrachloroethene (PCE) degradation to trichloroethene, cis-1,2-dichloroethene and vinyl chloride to evaluate the relationship between the microbial community and the potential accumulation or degradation of these toxic metabolites. Multiple soil microcosms supplied with different organic substrates were artificially contaminated with PCE. A thymidine analogue, bromodeoxyuridine (BrdU), was added to the microcosms and incorporated into the DNA of actively replicating cells. We compared the total and active bacterial communities during the 50-day incubations by using phylogenic microarrays and 454 pyrosequencing to identify microorganisms and functional genes associated with PCE degradation to ethene. By use of this integrative approach, both the key community members and the ecological functions concomitant with complete PCE degradation could be determined, including the presence and activity of microbial community members responsible for producing hydrogen and acetate, which are critical for Dehalococcoides-mediated PCE degradation. In addition, by correlation of chemical data and phylogenic microarray data, we identified several bacteria that could potentially oxidize hydrogen. These results demonstrate that PCE degradation is dependent on some microbial community members for production of appropriate metabolites, while other members of the community compete for hydrogen in soil at low redox potentials.

The change of microbial community from chlorinated solvent-contaminated groundwater after biostimulation using the metagenome analysis

“…We can concluded from this study: (1) the investigated microbial groundwater community was highly complex, and only a limited number of dominant species were present; (2) Ethene was detected at the contaminated sites, which indicated the occurrence of complete dechlorination of PCE/TCE; (3) It is likely that anaerobic and aerobic degradation of PCE/TCE can be stimulated using the indigenous dechlorinating consortia present at the contaminated site as inferred from the metagenome data.…”

“…Desulfovibrio has also been detected in TCE-consortia enriched on variety of electron donors [27]. Desulfuomonas is responsible for the reductive dechlorination of TCE [28] and could biodegrade PCE completely to ethene [1]. Dechloromonas spp.…”

“…Tetrachloroethene (PCE) and trichloroethene (TCE) are pollutants found in large quantities in industrial areas around the world [1]. They tend to accumulate at the bottom of aquifers originating from dense non-aqueous phase liquids (DNAPLs) that serve as reservoirs for long-term solubilization.…”

“…They tend to accumulate at the bottom of aquifers originating from dense non-aqueous phase liquids (DNAPLs) that serve as reservoirs for long-term solubilization. These pollutants can be degraded by microorganisms in a variety of ways, including reductive dechlorination under anaerobic conditions [1]. Incomplete biodegradation of PCE/TCE by some reductively dechlorinating bacteria [2] can cause the accumulation of cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC), which are toxic metabolites.…”

Metagenomic and Metatranscriptomic Analyses Reveal the Structure and Dynamics of a Dechlorinating Community Containing Dehalococcoides mccartyi and Corrinoid-Providing Microorganisms under Cobalamin-Limited Conditions

“…Metagenomics or 16S rRNA gene amplicon sequencing, sometimes followed by metatranscriptomics, has been successfully applied to a wide range of environmental microbiomes, including ocean surface waters (33,34), acid mine drainage (35), permafrost (32), and microbial fuel cells (36). Microbial compositions and functional genes of Dehalococcoidescontaining dechlorinating communities have been reported in several metagenomic studies (19,36,37), and the active community members and the genes involved in carbon metabolism in the community have been investigated by BrdU-incorporated DNA sequencing (38). Metatranscriptomics sequencing can further provide insights into a comprehensive profile of functional activity and dynamics, which is important for identifying the roles played by the supportive microorganisms in dechlorinating communities under various environmental conditions.…”