Coupled Adsorption and Biodegradation of Trichloroethylene on Biochar from Pine Wood Wastes: A Combined Approach for a Sustainable Bioremediation Strategy

Towards chlorinated solvents, the effectiveness of the remediation strategy can be improved by combining a biological approach (e.g., anaerobic reductive dechlorination) with chemical/physical treatments (e.g., adsorption). A coupled adsorption and biodegradation (CAB) process for trichloroethylene (TCE) removal is proposed in a biofilm–biochar reactor (BBR) to assess whether biochar from pine wood (PWB) can support a dechlorinating biofilm by combining the TCE (100 µM) adsorption. The BBR operated for eight months in parallel with a biofilm reactor (BR)—no PWB (biological process alone), and with an abiotic biochar reactor (ABR)—no dechlorinating biofilm (only an adsorption mechanism). Two flow rates were investigated. Compared to the BR, which resulted in a TCE removal of 86.9 ± 11.9% and 78.73 ± 19.79%, the BBR demonstrated that PWB effectively adsorbs TCE and slows down the release of its intermediates. The elimination of TCE was quantitative, with 99.61 ± 0.79% and 99.87 ± 0.51% TCE removal. Interestingly, the biomarker of the reductive dechlorination process, Dehalococcoides mccartyi, was found in the BRR (9.2 × 105 16S rRNA gene copies/g), together with the specific genes tceA, bvcA, and vcrA (8.16 × 106, 1.28 × 105, and 8.01 × 103 gene copies/g, respectively). This study suggests the feasibility of biochar to support the reductive dechlorination of D. mccartyi, opening new frontiers for field-scale applications.

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Unexpected Specificity of Interspecies Cobamide Transfer from Geobacter spp. to Organohalide-Respiring Dehalococcoides mccartyi Strains

Applied and Environmental Microbiology ◽

10.1128/aem.01535-12 ◽

2012 ◽

Vol 78 (18) ◽

pp. 6630-6636 ◽

Cited By ~ 80

Author(s):

Jun Yan ◽

Kirsti M. Ritalahti ◽

Darlene D. Wagner ◽

Frank E. Löffler

Keyword(s):

Reductive Dechlorination ◽

De Novo ◽

Synthetic Medium ◽

Geobacter Sulfurreducens ◽

Rrna Gene ◽

Content Type ◽

Reductive Dehalogenase ◽

Dehalococcoides Mccartyi ◽

Gene Copies ◽

Pure Cultures

ABSTRACTDehalococcoides mccartyistrains conserve energy from reductive dechlorination reactions catalyzed by corrinoid-dependent reductive dehalogenase enzyme systems.Dehalococcoideslacks the ability forde novocorrinoid synthesis, and pure cultures require the addition of cyanocobalamin (vitamin B12) for growth. In contrast,Geobacter lovleyi, which dechlorinates tetrachloroethene tocis-1,2-dichloroethene (cis-DCE), and the nondechlorinating speciesGeobacter sulfurreducenshave complete sets of cobamide biosynthesis genes and produced 12.9 ± 2.4 and 24.2 ± 5.8 ng of extracellular cobamide per liter of culture suspension, respectively, during growth with acetate and fumarate in a completely synthetic medium.G. lovleyi-D. mccartyistrain BAV1 or strain FL2 cocultures provided evidence for interspecies corrinoid transfer, andcis-DCE was dechlorinated to vinyl chloride and ethene concomitant withDehalococcoidesgrowth. In contrast, negligible increase inDehalococcoides16S rRNA gene copies and insignificant dechlorination occurred inG. sulfurreducens-D. mccartyistrain BAV1 or strain FL2 cocultures. Apparently,G. lovleyiproduces a cobamide that complementsDehalococcoides' nutritional requirements, whereasG. sulfurreducensdoes not. Interestingly,Dehalococcoidesdechlorination activity and growth could be restored inG. sulfurreducens-Dehalococcoidescocultures by adding 10 μM 5′,6′-dimethylbenzimidazole. Observations made with theG. sulfurreducens-Dehalococcoidescocultures suggest that the exchange of the lower ligand generated a cobalamin, which supportedDehalococcoidesactivity. These findings have implications forin situbioremediation and suggest that the corrinoid metabolism ofDehalococcoidesmust be understood to faithfully predict, and possibly enhance, reductive dechlorination activities.

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Correlations between maximum reductive dechlorination rates and specific biomass parameters in Dehalococcoides mccartyi consortia enriched on chloroethenes PCE, TCE, and cis-1,2-DCE

FEMS Microbiology Ecology ◽

10.1093/femsec/fiab064 ◽

2021 ◽

Author(s):

B Matturro ◽

M Majone ◽

F Aulenta ◽

S Rossetti

Keyword(s):

16S Rrna ◽

Reductive Dechlorination ◽

Correlation Factor ◽

16S Rrna Genes ◽

Rrna Genes ◽

Rrna Gene ◽

Activity Levels ◽

Dehalococcoides Mccartyi ◽

Gene Copies ◽

Specific Biomass

Abstract One of the challenges to implementing the modeling of the biological reductive dechlorination (RD) process is the evaluation of biological parameters that represent the abundance/activity levels of the microorganisms involved in the biodegradation of chloroethenes. Here we report a combined analysis of kinetic and specific biomass parameters conducted on three dechlorinating consortia enriched on PCE, TCE, and cis-1,2-DCE. In these consortia, Dehalococcoides mccartyi (Dhc) represented ≥ 70% of the bacterial population identified via 16S rRNA gene amplicon sequencing. Quantitative biomolecular methods were used to generate specific biomass parameters targeting either the Dhc population (16S rRNA genes or cells) or specific genes encoding RD process-involved reductive dehalogenases. The correlation factor between the abundance of active Dhc cells or tceA gene copies and maximum RD rates allowed to predict an increment of 7E+09 of active Dhc cells or 5E+09 tceA gene copies L−1 under controlled conditions. Diversely, the utilization of gene transcripts as biomass parameters for RD modeling did not provide reliable correlations with kinetic performances. This study provides valuable insights for further modeling of the RD process through the utilization of specific biomass parameters.

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A Microcosm Treatability Study for Evaluating Wood Mulch-Based Amendments as Electron Donors for Trichloroethene (TCE) Reductive Dechlorination

Water ◽

10.3390/w13141949 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1949

Author(s):

Edoardo Masut ◽

Alessandro Battaglia ◽

Luca Ferioli ◽

Anna Legnani ◽

Carolina Cruz Viggi ◽

...

Keyword(s):

Electron Donor ◽

Environmental Sustainability ◽

Reductive Dechlorination ◽

Environmental Remediation ◽

Low Cost ◽

Chlorinated Solvents ◽

Electron Donors ◽

Chlorinated Ethenes ◽

Dehalococcoides Mccartyi ◽

Wood Mulch

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes.

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Metagenomic Analysis Reveals Microbial Interactions at the Biocathode of a Bioelectrochemical System Capable of Simultaneous Trichloroethylene and Cr(VI) Reduction

Frontiers in Microbiology ◽

10.3389/fmicb.2021.747670 ◽

2021 ◽

Vol 12 ◽

Author(s):

Bruna Matturro ◽

Marco Zepilli ◽

Agnese Lai ◽

Mauro Majone ◽

Simona Rossetti

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Amplicon Sequencing ◽

Microbial Interactions ◽

Metagenomic Analysis ◽

Rrna Gene ◽

Shotgun Metagenomics ◽

Dehalococcoides Mccartyi ◽

Hydrogenotrophic Methanogenesis ◽

Gene Copies

Bioelectrochemical systems (BES) are attractive and versatile options for the bioremediation of organic or inorganic pollutants, including trichloroethylene (TCE) and Cr(VI), often found as co-contaminants in the environment. The elucidation of the microbial players’ role in the bioelectroremediation processes for treating multicontaminated groundwater is still a research need that attracts scientific interest. In this study, 16S rRNA gene amplicon sequencing and whole shotgun metagenomics revealed the leading microbial players and the primary metabolic interactions occurring in the biofilm growing at the biocathode where TCE reductive dechlorination (RD), hydrogenotrophic methanogenesis, and Cr(VI) reduction occurred. The presence of Cr(VI) did not negatively affect the TCE degradation, as evidenced by the RD rates estimated during the reactor operation with TCE (111±2 μeq/Ld) and TCE/Cr(VI) (146±2 μeq/Ld). Accordingly, Dehalococcoides mccartyi, the primary biomarker of the RD process, was found on the biocathode treating both TCE (7.82E+04±2.9E+04 16S rRNA gene copies g−1 graphite) and TCE/Cr(VI) (3.2E+07±2.37E+0716S rRNA gene copies g−1 graphite) contamination. The metagenomic analysis revealed a selected microbial consortium on the TCE/Cr(VI) biocathode. D. mccartyi was the sole dechlorinating microbe with H2 uptake as the only electron supply mechanism, suggesting that electroactivity is not a property of this microorganism. Methanobrevibacter arboriphilus and Methanobacterium formicicum also colonized the biocathode as H2 consumers for the CH4 production and cofactor suppliers for D. mccartyi cobalamin biosynthesis. Interestingly, M. formicicum also harbors gene complexes involved in the Cr(VI) reduction through extracellular and intracellular mechanisms.

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Chlorinated electron acceptor availability selects for specificDehalococcoidespopulations in dechlorinating enrichment cultures and in groundwater

10.1101/175182 ◽

2017 ◽

Cited By ~ 1

Author(s):

A. Pérez-de-Mora ◽

A. Lacourt ◽

M.L. McMaster ◽

X. Liang ◽

S.M. Dworatzek ◽

...

Keyword(s):

Electron Acceptor ◽

Groundwater Remediation ◽

Driving Forces ◽

Major Influence ◽

Rrna Gene ◽

Reductive Dehalogenase ◽

Dehalococcoides Mccartyi ◽

Gene Copies ◽

Field Samples ◽

The Uk

AbstractIndividualDehalococcoides mccartyi (Dhc)strains differ primarily from one another by the number and identity of the reductive dehalogenase homologous catalytic subunit A (rdhA) genes contained within their respective genomes. While thousands ofrdhAgenes have been sequenced, the activity of the corresponding proteins have been identified in only a handful of cases. Most effort has focused on identifying the enzymes that dechlorinate substrates including trichloroethene (TCE), cis-dichloroethene (cDCE) and vinyl chloride (VC) relevant to groundwater remediation. The associatedrdhAgenes, namelytceA, bvcA,andvcrA, along with theD. mccartyi16S rRNA gene are often used to track growth and dechlorinating activity in DNA extracted from field samples. In this study, we augmented the typical suite of three characterizedrdhAgenes to include an additional 12 uncharacterizedrdhAsequences identified in the metagenome in the mixedDhc-containing culture KB-1 to track population shifts within the culture and at two bioaugmented field sites. Quantitative PCR assays were developed for the 15 selectedD. mccartyi rdhAgenes and evaluated using 11 different sub-cultures of KB-1, each enriched on different chlorinated ethenes and ethanes. The proportion ofrdhAgene copies relative toDhc16S gene copies indicated the presence of multiple distinctDhcpopulations in each culture. The specific electron acceptor amended to each culture had a major influence on the distribution ofD. mccartyipopulations and their associatedrdhAgenes. We also surveyed the abundance ofrdhAgenes in samples obtained from two bioaugmented field sites. Growth of the dominantD. mccartyipopulation in the KB-1 inoculum was detected in the UK site samples. At both field sites, the measurement of relativerdhAabundances revaled significantD. mccartyipopulation shifts over time as dechlorination progressed from TCE through cDCE to VC and ethene, indicating that the selective pressure of the most abundant chlorinated electron acceptor that was observed in lab cultures was also occurring in the populations in the field. Understanding driving forces behindD. mccartyipopulation selection and activity is improving predictability of remediation performance at chlorinated solvent contaminated sites.

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Effects of the Feeding Solution Composition on a Reductive/Oxidative Sequential Bioelectrochemical Process for Perchloroethylene Removal

Processes ◽

10.3390/pr9030405 ◽

2021 ◽

Vol 9 (3) ◽

pp. 405

Author(s):

Edoardo Dell’Armi ◽

Marco Zeppilli ◽

Bruna Matturro ◽

Simona Rossetti ◽

Marco Petrangeli Papini ◽

...

Keyword(s):

Reductive Dechlorination ◽

Nitrate Reduction ◽

Coulombic Efficiency ◽

Reducing Power ◽

Mineral Medium ◽

Process Conditions ◽

Microbial Electrolysis Cells ◽

Dehalococcoides Mccartyi ◽

In Series ◽

Synthetic Groundwater

Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants due to their improper use in several industrial activities. Specialized microorganisms are able to perform the reductive dechlorination (RD) of high-chlorinated CAHs such as perchloroethylene (PCE), while the low-chlorinated ethenes such as vinyl chloride (VC) are more susceptible to oxidative mechanisms performed by aerobic dechlorinating microorganisms. Bioelectrochemical systems can be used as an effective strategy for the stimulation of both anaerobic and aerobic microbial dechlorination, i.e., a biocathode can be used as an electron donor to perform the RD, while a bioanode can provide the oxygen necessary for the aerobic dechlorination reaction. In this study, a sequential bioelectrochemical process constituted by two membrane-less microbial electrolysis cells connected in series has been, for the first time, operated with synthetic groundwater, also containing sulphate and nitrate, to simulate more realistic process conditions due to the possible establishment of competitive processes for the reducing power, with respect to previous research made with a PCE-contaminated mineral medium (with neither sulphate nor nitrate). The shift from mineral medium to synthetic groundwater showed the establishment of sulphate and nitrate reduction and caused the temporary decrease of the PCE removal efficiency from 100% to 85%. The analysis of the RD biomarkers (i.e., Dehalococcoides mccartyi 16S rRNA and tceA, bvcA, vcrA genes) confirmed the decrement of reductive dechlorination performances after the introduction of the synthetic groundwater, also characterized by a lower ionic strength and nutrients content. On the other hand, the system self-adapted the flowing current to the increased demand for the sulphate and nitrate reduction, so that reducing power was not in defect for the RD, although RD coulombic efficiency was less.

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Intragenomic and intraspecific heterogeneity in rrs may surpass interspecific variability in a natural population of Veillonella

Microbiology ◽

10.1099/mic.0.038224-0 ◽

2010 ◽

Vol 156 (7) ◽

pp. 2080-2091 ◽

Cited By ~ 28

Author(s):

Anne-Laure Michon ◽

Fabien Aujoulat ◽

Laurent Roudière ◽

Olivier Soulier ◽

Isabelle Zorgniotti ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Gene Diversity ◽

Natural Populations ◽

Variable Region ◽

Housekeeping Gene ◽

Single Copy ◽

Population Based ◽

Rrna Gene ◽

Gene Copies

As well as intraspecific heterogeneity, intragenomic heterogeneity between 16S rRNA gene copies has been described for a range of bacteria. Due to the wide use of 16S rRNA gene sequence analysis for taxonomy, identification and metagenomics, evaluating the extent of these heterogeneities in natural populations is an essential prerequisite. We investigated inter- and intragenomic 16S rRNA gene heterogeneity of the variable region V3 in a population of 149 clinical isolates of Veillonella spp. of human origin and in 13 type or reference Veillonella strains using PCR-temporal temperature gel electrophoresis (TTGE). 16S rRNA gene diversity was high in the studied population, as 45 different banding patterns were observed. Intragenomic heterogeneity was demonstrated for 110 (74 %) isolates and 8 (61.5 %) type or reference strains displaying two or three different gene copies. Polymorphic nucleotide positions accounted for 0.5–2.5 % of the sequence and were scattered in helices H16 and H17 of the rRNA molecule. Some of them changed the secondary structure of H17. Phylotaxonomic structure of the population based on the single-copy housekeeping gene rpoB was compared with TTGE patterns. The intragenomic V3 heterogeneity, as well as recombination events between strains or isolates of different rpoB clades, impaired the 16S rRNA-based identification for some Veillonella species. Such approaches should be conducted in other bacterial populations to optimize the interpretation of 16S rRNA gene sequences in taxonomy and/or diversity studies.

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Six species of nontuberculous mycobacteria carry non-identical 16S rRNA gene copies

Journal of Microbiological Methods ◽

10.1016/j.mimet.2018.08.012 ◽

2018 ◽

Vol 155 ◽

pp. 34-36

Author(s):

Keita Takeda ◽

Kinuyo Chikamatsu ◽

Yuriko Igarashi ◽

Yuta Morishige ◽

Yoshiro Murase ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Nontuberculous Mycobacteria ◽

Rrna Gene ◽

Gene Copies

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Parameter Determination for Reductive Dechlorination of Chlorinated Solvents

Transport in Porous Media ◽

10.1007/s11242-006-0001-4 ◽

2006 ◽

Vol 65 (3) ◽

pp. 411-424 ◽

Cited By ~ 2

Author(s):

Antónia Balážová ◽

Marián Slodička ◽

Roger Van Keer

Keyword(s):

Reductive Dechlorination ◽

Chlorinated Solvents ◽

Parameter Determination

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Development of an efficient PCR-based diagnosis protocol for the identification of the pinewood nematode, Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae)

Nematology ◽

10.1163/1568541041217915 ◽

2004 ◽

Vol 6 (2) ◽

pp. 279-285 ◽

Cited By ~ 39

Author(s):

Jae Soon Kang ◽

Kwang Sik Choi ◽

Sang Chul Shin ◽

Il Sung Moon ◽

Sang Gil Lee ◽

...

Keyword(s):

Intergenic Spacer ◽

Nematode Species ◽

Bursaphelenchus Xylophilus ◽

5S Rrna ◽

Rrna Gene ◽

Pinewood Nematode ◽

Pine Wood ◽

5S Rrna Gene ◽

Primer Sets ◽

Species Specific

Abstract Pine wood wilt disease caused by the pine wood nematode, Bursaphelenchus xylophilus , has been a serious problem in the southern regions of Korea. Efficient diagnosis of B. xylophilus from infected pine wood specimens is critical for the management of this pest. Traditional microscopic examination often results in an erroneous identification because a closely related non-pathogenic species, B. mucronatus, has a great degree of morphological similarity to B. xylophilus. In an attempt to search for reliable molecular markers for the discrimination of these species, we have cloned the 5S rRNA genomic DNA fragments containing both coding and intergenic spacer (IGS) regions from B. xylophilus and B. mucronatus through a homology-probing PCR strategy. Sequence analyses revealed that coding sequences of the 5S rRNA gene from the two species are almost identical (98.3% homology) but that the IGS sequences differ substantially between the species. Based on the IGS sequence differences (69.7% homology), we designed species-specific primer sets and developed a PCR-based diagnosis protocol for the identification and discrimination of the two nematode species on a molecular basis.

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