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Dehalococcoides

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Dehalococcoides
Scientific classification
Domain:
Bacteria
Phylum:
Chloroflexi
Class:
Dehalococcoidia
Genus:
Dehalococcoides
Maymo-Gatell et al. 1997
Species

Dehalococcoides is a genus of bacteria within class Dehalococcoidia that obtain energy via the oxidation of hydrogen and subsequent reductive dehalogenation of halogenated organic compounds in a mode of anaerobic respiration called organohalide respiration.[1] They are well known for their great potential to remediate halogenated ethenes and aromatics. They are the only bacteria known to transform highly chlorinated dioxins, PCBs. In addition, they are the only known bacteria to transform tetrachloroethene (perchloroethene, PCE) to ethene.

Microbiology

The first member of the genus Dehalococcoides was described in 1997 as Dehalococcoides ethenogenes strain 195. Additional Dehalococcoides members were later described as strains CBDB1,[2] BAV1, FL2, VS, and GT. In 2012 all yet-isolated Dehalococcoides strains were summarized under the new taxonomic name D. mccartyi.[3]

Activities

Dehalococcoides are obligately organohalide-respiring bacteria,[3] meaning that they can only grow by using halogenated compounds as electron acceptors. Currently, hydrogen (H2) is often regarded as the only known electron donor to support growth of dehalococcoides bacteria.[4][5][6] However, studies have shown that utilizing various electron donors such as formate,[7] and methyl viologen,[5] have also been effective in promoting growth for various species of dehalococcoides. In order to perform reductive dehalogenation processes, electrons are transferred from electron donors through dehydrogenases, and ultimately utilized to reduce halogenated compounds,[3] many of which are human-synthesized chemicals acting as pollutants.[8] Furthermore, it has been shown that a majority of reductive dehalogenase activities lie within the extracellular and membranous components of D. ethenogenes, indicating that dechlorination processes may function semi-independently from intracellular systems.[5] Currently, all known dehalococcoides strains require acetate for producing cellular material, however, the underlying mechanisms are not well understood as they appear to lack fundamental enzymes that complete biosynthesis cycles found in other organisms.[6]

Dehalococcoides can transform many highly toxic and/or persistent compounds. This includes tetrachloroethene (PCE) and trichloroethene (TCE) which are transformed to non-toxic ethene, and chlorinated dioxins, vinyl chloride, benzenes, polychlorinated biphenyls (PCBs), phenols and many other aromatic contaminants.[9][10][11]

Applications

Dehalococcoides can uniquely transform many highly toxic and/or persistent compounds that are not transformed by any other known bacteria, in addition to halogenated compounds that other common organohalide respirers utilize.[8][12] For example, common compounds such as chlorinated dioxins, benzenes, PCBs, phenols and many other aromatic substrates can be reduced into less harmful chemical forms.[8] However, dehalococcoides are currently the only known dechlorinating bacteria with the unique ability to degrade the highly recalcitrant, tetrachloroethene (PCE) and tricholoroethene (TCE) compounds into less-toxic forms that are more suitable for environmental conditions, and thus utilized in bioremediation.[8][13][7] Their capacity to grow by using contaminants allows them to proliferate in contaminated soil or groundwater, offering promise for in situ decontamination efforts.

The process of transforming halogenated pollutants to non-toxic compounds involves different reductive enzymes. D. mccartyi strain BAV1 is able to reduce vinyl chloride, a toxic contaminant that usually originates from landfills, to ethene by using a special vinyl chloride reductase thought to be coded for by the bvcA gene.[14] A chlorobenzene reductive dehalogenase has also been identified in the strain CBDB1.[15]

Several companies worldwide now use Dehalococcoides-containing mixed cultures in commercial remediation efforts. In mixed cultures, other bacteria present can augment the dehalogenation process by producing metabolic products that can be used by Dehalococcoides and others involved in the degradation process.[9][16] For example, Dehalococcoides sp. strain WL can work alongside Dehalobacter in a step-wise manner to degrade vinyl chloride: Dehalobacter converts 1,1,2-TCA to vinyl chloride, which is subsequently degraded by Dehalococcoides.[17] Also, the addition of electron acceptors is needed - they are converted to hydrogen in situ by other bacteria present, which can then be used as an electron source by Dehalococcoides.[12][9] MEAL (a methanol, ethanol, acetate, and lactate mixture) is documented to have been used as substrate.[18] In the US, BAV1 was patented for the in situ reductive dechlorination of vinyl chlorides and dichloroethenes in 2007.[19] D. mccartyi in high-density dechlorinating bioflocs have also been used in ex situ bioremediation.[20]

Although dehalococcoides have been shown to reduce contaminants such as PCE and TCE, it appears that individual species have various dechlorinating capabilities which contributes to the degree that these compounds are reduced. This could have implications on the effects of bioremediation tactics.[13] For example, particular strains of dehalococcoides have shown preference to produce more soluble, carcinogenic intermediates such as 1,2–dichloroethene isomers and vinyl chloride that contrasts against bioremediation goals, primarily due to their harmful nature.[4][8] Therefore, an important aspect of current bioremediation tactics involves the utilization of multiple dechlorinating organisms to promote symbiotic relationships within a mixed culture to ensure complete reduction to less-toxic ethene.[13] As a result, studies have focused upon metabolic pathways and environmental factors that regulate reductive dehalogenative processes in order to better implement dehalococcoides for bioremediation tactics.[8]

However, not all members of Dehalococcoides can reduce all halogenated contaminants. Certain strains cannot use PCE or TCE as electron acceptors (e.g. CBDB1) and some cannot use vinyl chloride as an electron acceptor (e.g. FL2).[14] D. mccartyi strains 195 and SFB93 are inhibited by high concentrations of acetylene (which builds up in contaminated groundwater sites as a result of TCE degradation) via changes in gene expression that likely disrupt normal electron transport chain function.[9] When selecting Dehalococcoides strains for bioremediation use, it is important to consider their metabolic capabilities and their sensitivities to different chemicals.

Protocols for setting up microcosoms in lab

This protocol consists of two steps, sampling at site and subsequent setting up of microcosms.

A. Sampling at sites.

Choose those sites which may be contaminated by TCE or PCE before. Collect some sludge sample into a sealed container and bring it back to the anaerobic chamber ASAP.

1) Set the targeted sites first, and prepare enough 50-ml sterile falcon tubes (at least 2-3 tubes per site) and label them with permanent marker. 2) Bring spatula, 70% ethanol spray bottle, gloves, tissue, water (for wash hands after sampling-optional), and bags for solid samples to the sites. For liquid samples, it may be helpful to bring the pipette (10-ml) or autoclaved sealed duran bottles flushed with N2 as headspace. Label it properly. Bring an ice box for temporary storage if possible. 3) During sampling, ensure minimal exposure to oxygen, e.g., For liquid samples, fill tubes up as full as possible with liquid samples and if possible, avoid capping tubes in air. For solid samples, fill up tube with liquid sample or ultrapure water (for solid, dry sample). Minimize cross contamination between samples as much as possible. 4) Keep the microcosms at 4 °C when back to the lab. Setting up the microcosms as soon as possible. If not, better to freeze the samples at -20 °C.

Before experiment, check whether the anaerobic chamber is in good condition for working and the outlet pressure for both N2 and anaerobic mixed gas should be at 10 psi.

B. Setting up microcosms at lab

1) Wash enough serum bottles (according to the number of microcosms) with ultrapure water and dry it in the oven at about 100 °C for 1 h. Rinse the black stoppers, put it into a glass beaker then dry it at 60-70 °C for 2 h. 2) Cover the serum bottles (or 60 ml serum bottles) individually and the beaker (containing stoppers) with aluminum foil. Then go to autoclave. Be reminded to set the control bottles together with the sampling bottles in duplicate). After autoclave, mark the serum bottles and label them on the tape properly. 3) Prepare 2000 ml of medium according to Table 4 (at least 120 ml of medium for each microcosm). Under flushing of N2 (minimum flow rate, about 1 psi), bring the medium solution to boil fully (100 °C). Once the solution starts to boil, let it boil for another 10min before removing it from the heater.

4) Cool the medium solution to room temperature under higher flow rate of N2 (about 4-5 psi). Next, add the reducing agents in Table 5 to the medium solution quickly so as not to introduce too much O2 into the medium.

5) Mix the solution (using magnetic stir bar) to fully dissolve the chemicals. Medium should turn colourless.

6) Insert a pH probe into the solution. Adjust the pH through different flowrate of N2/CO2. Let the pH rise until 7.2 – 7.3.

7) When pH meter shows the desired pH, seal the three-neck round bottom flask with stoppers (rubber or glass) and parafilm the necks to maintain anaerobic conditions. Next, autoclave the flask at 121°C, 20 min, 210 kPa.

8) Once done, transfer the flask along with the necessary items: e.g. spatula, tissue, oxygen indicator, 60-ml syringe for media dispensing, catalyst panel and a small beaker, 70% ethanol spray bottle, gloves (one pair of gloves for each microcosm to prevent cross-contamination), autoclaved serum bottles, aluminum caps, black butyl rubber stoppers, crimper, biohazard/trash bag, vitamin inside the disposable syringe, paper for the working bench, and other stuff deemed necessary) into the anaerobic chamber. Loosen the caps of spray bottle (ethanol) or water bottle if applicable. Punch holes on aluminum foils for serum bottles/stopper beaker with disposable needle to allow residual O2 in the bottles to be vacuumed.

9) Check whether the water level inside the anaerobic chamber in between the 2 black lines. If not, adjust the water level by removing extra water or adding necessary amount of ultra pure water.

10) Place them into the side chamber and close the door, then press “autocycle”. Once ready, the chamber panel will indicate “anaerobic” (light on). Then place two arms inside the gloves and ensure good sealing (no leakage). Use foot to replace the air inside the arm with N2 or mixed gas by stepping on the “Vacuum” followed by “Gas” foot panel. Repeat this cycle for 2-3 times. Then enter the main chamber with two arms by gently loosing the two front doors simultaneously.

11) Once enter the main anaerobic chamber, replace the present “old” catalyst in the anaerobic chamber with the “new” one. Remove the extra water from the small beaker inside the main chamber or change a new beaker.

12) Open the oxygen indicator. Wait until it turns relatively clear then start work inside the chamber. During this process, put one layer of bench-work paper inside the chamber to maintain the cleanliness of the main chamber. Wipe the working area with 70% alcohol.

13) Sterilize gloves. Add the required amount of filter-sterilized vitamins directly into the medium in the three-neck flask and gently shake to ensure minimal agitation (to reduce the chance for media to turn pink). Transfer (about 10 g if solid and 10 ml if liquid) microcosm material (e.g. soil, sediment) into the autoclaved serum bottles using spatula (solid) or syringe/manually pouring (liquid). Sterilize the gloves or change to a new pair of gloves when handling with different microcosms.

14) Add the required amount of medium (about 25-ml for 60-ml serum bottle, 40-100 ml for 160 ml serum bottle) into the serum bottles using a 60-ml syringe and seal with rubber septa and finally crimp using crimper. It is advisable to allow the medium in the flask to ideally turn clear before dispensing to the serum bottles INSIDE the anaerobic chamber.

15) When done, remove everything that does not belong in the chamber (e.g. any trash and old catalyst panel) and clean up any mess.

16) Add the substrate in the fume hood (outside the chamber) if the substrate is toxic, e.g. TCE (with disposable syringe and needles).

How to prepare medium in lab to grow Dehalococcoides spp. anaerobically I. Reagents Table 1: Trace element solution (1000×) Chemicals used Amount ml g HCl (25% solution, w/w) 10 - FeCl2.4H2O - 1.5 CoCl2.6H2O - 0.19 MnCl2.4H2O - 0.1 ZnCl2 - 0.07 H3BO3 - 0.006 Na2MoO4.2H2O - 0.036 NiCl2.6H2O - 0.024 CuCl2.2H2O - 0.002


Table 2: Se/W Solution (1000×) Chemicals used Amount ml g Na2SeO3.5H2O - 0.006 Na2WO4.2H2O - 0.008 NaOH - 0.5


Table 3: Salts Solution (100×) Chemicals used Amount (1 x g/L) Amount (100xg/L) Amount (g/100ml)

NaCl 1.0 100.0 10.0 MgCl2.6H2O 0.5 50.0 5.0 KH2PO4 0.2 20.0 2.0 NH4Cl 0.3 30.0 3.0 KCl 0.3 30.0 3.0 CaCl2.2H2O 0.015 1.5 0.15

Table 4: Medium Solution (carbon source: acetate 5 mM) for 1000 ml Chemicals used Amount (1L) ml g 100 x salt solutions 10 - Trace element (1000×) 1 - Se/W Solution (1000×) 1 - TES (10mM) - 2.292 Resazurin (0.1% solution) 0.25 - Sodium acetate (5 mM) - 0.6804 milli-Q water Top up - (carbon source can be lactate which needs to be added after autoclave or acetate which can be added after boiling)

Table 5: Reductants and buffering agent Chemicals used Amount (1L) ml g 0.2mM L-cysteine - 0.0242 0.2mM Na2S.9H2O - 0.048 0.5mM DL-dithiothreitol (DTT) - 0.0771 30mM NaHCO3 - 2.52

Table 6: Vitamin and Vitamin B12 Solution (1000×) Chemicals used Amount (1L) ml mg Biotin - 20 Folic acid - 20 Pyridoxine Hydrochloride - 100 Riboflavin - 50 Thiamin - 50 Nicotinic acid - 50 Pantothenic acid - 50 p-aminobenzoic acid - 50 Thioctic acid - 50 Vitamin B12 - 1

Table 7: Preparation of additional vitamin B12 solution Vitamin B12 50mg 0.05 0.01mg


How to prepare the medium

Step 1: Preparation of medium solution

Prepare trace element solution according to Table 1. Prepare Se/W solution according to Table 2. Prepare 100ml salt solution according to Table 3. Prepare 200ml of medium according to Table 4. Under flushing of N2 (minimum flow rate), bring the medium solution to boil fully (100 degree C). Once the solution starts to boil, let it boil for another 10min before removing it from the heater. Cool the medium solution to room temperature under higher flow rate of N2. Next, add the chemicals in Table 5 to the medium solution quickly so as not to introduce too much O2 into the medium. Shake the solution to fully dissolve the chemicals. Medium should turn colourless. Insert a pH probe into the solution. Let the pH rise until 7.2 – 7.3. Adjust the pH through different flowrate of N2/CO2. Flush the test tubes with N2/CO2 (80/20). Flush the syringe used for dispensing by drawing N2/CO2 from the medium solution 2 to 3 times. Once the pH rises to 7.2, start to dispense 9ml of medium into test tubes. Take note not to draw air into the syringe. Close the tubes with blue rubber stopper and crimped sealed with aluminium caps to ensure no leakage. Maintain the pH of the medium during dispensing to be 7.2-7.3 by flushing with N2/CO2 (90/10) once the pH rise above 7.3. Autoclave the test tubes at 121oC, 20min, 210 kPa. The medium solution should be clear after autoclave. Discard any medium solution that is pink a day after autoclave.

Step 2: Preparation of vitamins solution and vitamin B12

Prepare a 200x vitamins solution according to Table 6. Also, prepare a 200x vitamin B12 solution by dissolving 0.02mg in 1L of DI water Shake well to dissolve the contents. Use aluminium foil to wrap the bottle as the vitamins solution are light sensitive. Adjust the pH of the vitamins solution using 10M NaOH to 7.5 Prepare two 160ml bottles flushed with N2, close with rubber stopper and sealed with aluminium cap, autoclave at 121oC, 20 min, 210kPa Due to heat sensitivity of the vitamins solution, sterilise the vitamins solution and vitamin B12 by filtering the solution through a sterile filter into the autoclaved 160ml bottle (flushed with N2). Wrap the two 160ml bottle filled with sterilized vitamins solution and vitamin B12 with aluminium foil and store in refrigerator.

Step 3: Addition of vitamins solution and vitamin B12 and TCE to the medium test tubes

Perform the addition of vitamins solution in the class II biosafety cabinet. "On" the biosafety cabinet and ensure that the air flow is stable (green region) Swap the working surface with 70% ethanol to disinfect. Prepare a bottle flushed with N2, autoclaved for reducing. Disinfect the surface of the 2 bottle of vitamins solution and vitamin B12 with 70% ethanol, flame the ethanol swapped surface to burn off completely. Repeat the disinfection step in step 5 for the medium test tubes. Using disposable 1ml syringe attached to a new needle (let it be needle 1), reduce the syringe 2-3 times by drawing N2 from the autoclaved bottle. Invert the vitamins solution and insert the needle fully through the rubber stoppers and draw 1ml of vitamin solutions. Remove the needle and attach the same syringe to a sterile 0.2µm filter with a new needle (let it be needle 2). Filter the vitamins solution in the syringe through the sterile filter. Detach the sterile filter and needle (taking care not to contaminate) and fix the same syringe back to needle 1. Invert the vitamins solution bottle and draw another 1ml. Detach needle 1 and fix to previous sterile filter attached to needle 2. Push the syringe to get rid of any air bubbles trapped. Invert the vitamins solution bottle and insert needle 2 into the medium test tubes and add 0.05ml to each test tubes. Invert the test tubes immediately after withdrawing the needle to minimize possible leakage of the rubber stopper. After the addition of vitamins, proceed to add TCE to each of the medium test tubes. Perform the addition of TCE in the fume hood (ensure exhaust is working well). Add a drop (equivalent to 2µl TCE) into each of the medium test tubes. Label the test tubes according to the no. of drops of TCE added. Leave the test tubes overnight at room temperature and observe for any changes in medium colour to pink.

Step 4: Inoculation of mixed culture to the medium test tubes

Proceed the inoculation for those test tubes that remain clear after overnight (indication of absence of O2) Prepare 2 sets of medium test tubes for duplicate results until dilution (-6). Total no. of medium test tubes needed is 12. Perform the inoculation in the biosafety cabinet "On" the biosafety cabinet and ensure that the air flow is stable (green region) Swap the working surface with 70% ethanol to disinfect. Using disposable 1ml syringe attached to a new needle, reduce the syringe 2-3 times by drawing N2 from the autoclaved bottle. Disinfect the surface of the mixed culture bottle with 70% ethanol, flame the ethanol swapped surface to burn off completely. Repeat the disinfection step in step 6 for the medium test tubes. Invert the mixed culture bottle and draw 2ml of mixed culture with the syringe. Inoculate 1ml each into two medium test tubes. Invert the inoculated test tubes a few times to mix well. Using a new syringe and needle, invert the first inoculated test tube and withdraw 1ml of solution and transfer to the 2nd medium test tube (dilution 10-1). Invert the 2nd medium test tube a few times before drawing 1ml for transfer to the 3rd test tube. Continue the serial dilution step for the rest of the medium test tubes using the same syringe and needle until dilution 10-6. Label the dilution factor on the test tube. Repeat step 11 to 13 for the duplicate set. Incubate the inoculated test tubes at 30oC with the stopper down.


Step 5: Using Gas Chromatograph (GC) equipped with FID to detect the activity of ananerobic bacterium

Chorinated aliphatic hydrocarbons including PCE, TCE, cis-TCE, trans-DCE, 1,1-DCE were purchased from Sigma-Aldrich-Fluka. Prepare a standard MIX containing all the 5 chemicals above by adding 2µl of each chemical into the same autoclaved blank medium. Prepare another 5 standards by adding 2µl of each chemical individually into each bottle. By trial and error, develop a method in the GC which can detect the chemicals present in the standards. Using a sterile 1ml syringe, draw suitable volume (e.g. 50µl or 100µl depending on the concentration) from the headspace of the standard MIX into the GC and record down the retention time, peak area and peak height. Repeat the same for the other individual standards of the 5 chemicals. Measure the initial concentration of the TCE in the headspace of the medium bottles by drawing suitable volumes for GC analysis. Monitor the dechlorinating activity of the inoculated medium bottles weekly by GC-FID analysis. Compare the results with the standards.

Note: this protocol can be used for any Dehalococcoides spp.

== How to obtain Dehalococcoides isolates ==


Series dilution to extinction method in both liquid medium and agar shake. The key to obtain the pure culture is to apply antibiotic (ampicillin) to the medium, both liquid and solid agar.

Genomes

Several strains of Dehalococcoides sp. has been sequenced.[21][22][23] They contain between 14 and 36 reductive dehalogenase homologous (rdh) operons each consisting of a gene for the active dehalogenases (rdhA) and a gene for a putative membrane anchor (rdhB). Most rdh-operons in Dehalococcoides genomes are preceded by a regulator gene, either of the marR-type (rdhR) or a two-component system (rdhST). Dehalococcoides have very small genomes of about 1.4-1.5 Mio base pairs. This is one of the smallest value for free-living organisms.

Biochemistry

Dehalococcoides strains do not seem to encode quinones but respire with a novel protein-bound electron transport chain.[24]

See also

References

  1. ^ "Dehalococcoides". NCIB Taxonomy Browser.
  2. ^ Adrian L, Szewzyk U, Wecke J, Görisch H (2000). "Bacterial dehalorespiration with chlorinated benzenes". Nature. 408 (6812): 580–583. doi:10.1038/35046063. PMID 11117744.
  3. ^ a b c Loffler, F. E.; Yan, J.; Ritalahti, K. M.; Adrian, L.; Edwards, E. A.; Konstantinidis, K. T.; Muller, J. A.; Fullerton, H.; Zinder, S. H.; Spormann, A. M. (2012). "Dehalococcoides mccartyi gen. nov., sp. nov., obligately organohalide-respiring anaerobic bacteria relevant to halogen cycling and bioremediation, belong to a novel bacterial class, Dehalococcoidia classis nov., order Dehalococcoidales ord. nov. and family Dehalococcoidaceae fam. nov., within the phylum Chloroflexi". International Journal of Systematic and Evolutionary Microbiology. 63 (Pt 2): 625–635. doi:10.1099/ijs.0.034926-0. ISSN 1466-5026. PMID 22544797.
  4. ^ a b Cheng, Dan; He, Jianzhong (15 September 2009). "Isolation and Characterization of "Dehalococcoides" sp. Strain MB, Which Dechlorinates Tetrachloroethene to trans-1,2-Dichloroethene". Applied and Environmental Microbiology. 75 (18): 5910–5918. doi:10.1128/AEM.00767-09. PMC 2747852. PMID 19633106.
  5. ^ a b c Nijenhuis, Ivonne; Zinder, Stephen H. (1 March 2005). "Characterization of Hydrogenase and Reductive Dehalogenase Activities of Dehalococcoides ethenogenes Strain 195". Applied and Environmental Microbiology. 71 (3): 1664–1667. doi:10.1128/AEM.71.3.1664-1667.2005. PMC 1065153. PMID 15746376.
  6. ^ a b Tang, Yinjie J.; Yi, Shan; Zhuang, Wei-Qin; Zinder, Stephen H.; Keasling, Jay D.; Alvarez-Cohen, Lisa (15 August 2009). "Investigation of Carbon Metabolism in "Dehalococcoides ethenogenes" Strain 195 by Use of Isotopomer and Transcriptomic Analyses". Journal of Bacteriology. 191 (16): 5224–5231. doi:10.1128/JB.00085-09.
  7. ^ a b Mayer-Blackwell, Koshlan; Azizian, Mohammad F.; Green, Jennifer K.; Spormann, Alfred M.; Semprini, Lewis (7 February 2017). "Survival of Vinyl Chloride Respiring dehalococcoides mccartyi under Long-Term Electron Donor Limitation". Environmental Science & Technology. 51 (3): 1635–1642. doi:10.1021/acs.est.6b05050.
  8. ^ a b c d e f Maphosa, Farai; Lieten, Shakti H.; Dinkla, Inez; Stams, Alfons J.; Smidt, Hauke; Fennell, Donna E. (2 October 2012). "Ecogenomics of microbial communities in bioremediation of chlorinated contaminated sites". Frontiers in Microbiology. 3: 351. doi:10.3389/fmicb.2012.00351. PMC 3462421. PMID 23060869.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  9. ^ a b c d Mao, Xinwei; Oremland, Ronald S.; Liu, Tong; Gushgari, Sara; Landers, Abigail A.; Baesman, Shaun M.; Alvarez-Cohen, Lisa (2017-02-21). "Acetylene Fuels TCE Reductive Dechlorination by Defined Dehalococcoides/Pelobacter Consortia". Environmental Science & Technology. 51 (4): 2366–2372. doi:10.1021/acs.est.6b05770. ISSN 0013-936X.
  10. ^ Lu, Gui-Ning; Tao, Xue-Qin; Huang, Weilin; Dang, Zhi; Li, Zhong; Liu, Cong-Qiang (2010). "Dechlorination pathways of diverse chlorinated aromatic pollutants conducted by Dehalococcoides sp. strain CBDB1". Science of the Total Environment. 408 (12): 2549–2554. doi:10.1016/j.scitotenv.2010.03.003.
  11. ^ Fennell, Donna E.; Nijenhuis, Ivonne; Wilson, Susan F.; Zinder, Stephen H.; Häggblom, Max M. (2004-04-01). "Dehalococcoides ethenogenes Strain 195 Reductively Dechlorinates Diverse Chlorinated Aromatic Pollutants". Environmental Science & Technology. 38 (7): 2075–2081. doi:10.1021/es034989b. ISSN 0013-936X.
  12. ^ a b Maymó-Gatell, Xavier; Chien, Yueh-tyng; Gossett, James M.; Zinder, Stephen H. (1997-06-06). "Isolation of a Bacterium That Reductively Dechlorinates Tetrachloroethene to Ethene". Science. 276 (5318): 1568–1571. doi:10.1126/science.276.5318.1568. ISSN 0036-8075. PMID 9171062.
  13. ^ a b c Grostern, Ariel; Edwards, Elizabeth A. (2006). "Growth of Dehalobacter and Dehalococcoides spp. during Degradation of Chlorinated Ethanes". Applied and Environmental Microbiology. 72 (1): 428–436. doi:10.1128/AEM.72.1.428-436.2006. PMC 1352275. PMID 16391074.
  14. ^ a b Krajmalnik-Brown, Rosa; Hölscher, Tina; Thomson, Ivy N.; Saunders, F. Michael; Ritalahti, Kirsti M.; Löffler, Frank E. (2004-10-01). "Genetic Identification of a Putative Vinyl Chloride Reductase in Dehalococcoides sp. Strain BAV1". Applied and Environmental Microbiology. 70 (10): 6347–6351. doi:10.1128/aem.70.10.6347-6351.2004. ISSN 0099-2240. PMC 522117. PMID 15466590.
  15. ^ Adrian, Lorenz; Rahnenführer, Jan; Gobom, Johan; Hölscher, Tina (2007-12-01). "Identification of a Chlorobenzene Reductive Dehalogenase in Dehalococcoides sp. Strain CBDB1". Applied and Environmental Microbiology. 73 (23): 7717–7724. doi:10.1128/aem.01649-07. ISSN 0099-2240. PMC 2168065. PMID 17933933.
  16. ^ Duhamel, Melanie; Edwards, Elizabeth A. (2006-12-01). "Microbial composition of chlorinated ethene-degrading cultures dominated by Dehalococcoides". FEMS Microbiology Ecology. 58 (3): 538–549. doi:10.1111/j.1574-6941.2006.00191.x. ISSN 0168-6496. PMID 17117995.
  17. ^ Grostern, Ariel; Edwards, Elizabeth A. (2006-01-01). "Growth of Dehalobacter and Dehalococcoides spp. during Degradation of Chlorinated Ethanes". Applied and Environmental Microbiology. 72 (1): 428–436. doi:10.1128/aem.72.1.428-436.2006. ISSN 0099-2240. PMC 1352275. PMID 16391074.
  18. ^ McKinsey, P.C. (February 20, 2003). "Bioremediation of Trichloroethylene-Contaminated Sediments Augmented with a Dehalococcoides Consortia". Retrieved October 8, 2017.
  19. ^ Loeffler, Frank (May 3, 2007). "United States Patent Application 20070099284". Retrieved 2017-10-09.
  20. ^ Fajardo-Williams, Devyn (2015). "Coupling Bioflocculation of Dehalococcoides to High-Dechlorination Rates for Ex situ and In situ Bioremediation". ProQuest.
  21. ^ Kube, M.; Beck, A.; Zinder, SH.; Kuhl, H.; Reinhardt, R.; Adrian, L. (Oct 2005). "Genome sequence of the chlorinated compound-respiring bacterium Dehalococcoides species strain CBDB1". Nat Biotechnol. 23 (10): 1269–73. doi:10.1038/nbt1131. PMID 16116419.
  22. ^ Seshadri, R.; Adrian, L.; Fouts, DE.; Eisen, JA.; Phillippy, AM.; Methe, BA.; Ward, NL.; Nelson, WC.; et al. (Jan 2005). "Genome sequence of the PCE-dechlorinating bacterium Dehalococcoides ethenogenes". Science. 307 (5706): 105–8. doi:10.1126/science.1102226. PMID 15637277.
  23. ^ Pöritz, M.; Goris, T.; Wubet, T.; Tarkka, MT.; Buscot, F.; Nijenhuis, I.; Lechner, U.; Adrian, L. (Jun 2013). "Genome sequences of two dehalogenation specialists – Dehalococcoides mccartyi strains BTF08 and DCMB5 enriched from the highly polluted Bitterfeld region". FEMS Microbiol Lett. 343 (2): 101–4. doi:10.1111/1574-6968.12160. PMID 23600617.
  24. ^ Kublik, Anja; Deobald, Darja; Hartwig, Stefanie; Schiffmann, Christian L.; Andrades, Adarelys; von Bergen, Martin; Sawers, R. Gary; Adrian, Lorenz (2016-09-01). "Identification of a multi-protein reductive dehalogenase complex in Dehalococcoides mccartyi strain CBDB1 suggests a protein-dependent respiratory electron transport chain obviating quinone involvement". Environmental Microbiology. 18 (9): 3044–3056. doi:10.1111/1462-2920.13200. ISSN 1462-2920. PMID 26718631.
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