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Biodegradation of high concentrations of halomethanes by a fermentative enrichment culture.

Shan H, Wang H, Yu R, Jacob P, Freedman DL - AMB Express (2014)

Bottom Line: CT (15 mg/L) and CFC-11 (25 mg/L) were also biodegraded without significant accumulation of halomethane daughter products.The highest rate of CF biodegradation occurred at pH 7.7; activity decreased substantially below pH 6.0.Overall, the results suggest that DHM-1 may be effective for bioaugmentation in source zones contaminated with thousands of milligrams per liter of CF and tens of milligrams per liter of CT and CFC-11.

View Article: PubMed Central - HTML - PubMed

Affiliation: PeroxyChem Environmental Solutions (East Asia), Room 5B16, West Wing, Hanwei Plaza, 7 Guanghua Road, Chaoyang District, Beijing 100004, China.

ABSTRACT
A fermentative enrichment culture (designated DHM-1) that grows on corn syrup was evaluated for its ability to cometabolically biodegrade high concentrations of chloroform (CF), carbon tetrachloride (CT), and trichlorofluoromethane (CFC-11). When provided with corn syrup and vitamin B12 (0.03 mol B12 per mol CF), DHM-1 grew and biodegraded up to 2,000 mg/L of CF in 180 days, with only minor transient accumulation of dichloromethane and chloromethane. CT (15 mg/L) and CFC-11 (25 mg/L) were also biodegraded without significant accumulation of halomethane daughter products. The rate of CF biodegradation followed a Michaelis-Menten-like pattern with respect to the B12 concentration; one-half the maximum rate (66 mg CF/L/d) occurred at 0.005 mol B12 per mol CF. DHM-1 was able to biodegrade 500 mg/L of CF at an inoculum level as low as 10(-8) mg protein/L. The highest rate of CF biodegradation occurred at pH 7.7; activity decreased substantially below pH 6.0. DHM-1 biodegraded mixtures of CT, CFC-11, and CF, although CFC-11 inhibited CF biodegradation. Evidence for compete defluorination of CFC-11 was obtained based on a fluoride mass balance. Overall, the results suggest that DHM-1 may be effective for bioaugmentation in source zones contaminated with thousands of milligrams per liter of CF and tens of milligrams per liter of CT and CFC-11.

No MeSH data available.


Related in: MedlinePlus

Behavior of a mixture of halomethanes in controls (a, b and c) and (d) live bottles with DHM-1 and corn syrup + B12in MSM. ↓ = addition of corn syrup; ◊ = addition of B12; ⇩ = reinoculation with DHM-1; WC = water controls, MC + B12=mediacontrol with B12, and AC = autoclaved control with B12. Averages forduplicate bottles are shown. Error bars in panel d represent the datarange; when not visible, the bars are smaller than the symbols.
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Figure 7: Behavior of a mixture of halomethanes in controls (a, b and c) and (d) live bottles with DHM-1 and corn syrup + B12in MSM. ↓ = addition of corn syrup; ◊ = addition of B12; ⇩ = reinoculation with DHM-1; WC = water controls, MC + B12=mediacontrol with B12, and AC = autoclaved control with B12. Averages forduplicate bottles are shown. Error bars in panel d represent the datarange; when not visible, the bars are smaller than the symbols.

Mentions: When CT, CFC-11, and CF (11, 24, and 500 mg/L, respectively) were added at the same time, the pattern of transformation was similar to the two-component mixtures. CT (12 μmol/bottle) transformation was completed first, followed by CFC-11 (57 μmol/bottle) and then CF (456 μmol/bottle) (Figure 7d). One difference between the live treatments shown in Figures 6 and 7d is the pattern of B12 addition. With the two-component mixtures (Figure 6), B12 was added only at the start. With the three-component mixture (Figure 7d), the same molar ratio of B12 was applied, although the additions were timed to coincide with the beginning of transformation of each compound. Accumulation of CS2, DCM, CM, HCFC-21, and HCFC-31 was negligible. Results for controls are shown in Figure 7, panels a, b and c. Nearly complete transformation of CT occurred by day 113 in the media control and AC, versus no significant losses from the WC. Approximately 33% and 11% of CFC-11 was removed in the autoclaved and media controls, respectively, while loss of CFC-11 in WC was minor. Losses of CF in all of the controls were minor. These results demonstrated that transformation of CF was exclusively a biotic process, while abiotic processes contributed to transformation of CT and CFC-11. However, transformation of CT and CFC-11 was considerably faster in the presence of live cells, and DHM-1 was able to achieve complete transformation of a mixture of CT, CFC-11 and CF at high initial concentrations in less than four months in MSM.


Biodegradation of high concentrations of halomethanes by a fermentative enrichment culture.

Shan H, Wang H, Yu R, Jacob P, Freedman DL - AMB Express (2014)

Behavior of a mixture of halomethanes in controls (a, b and c) and (d) live bottles with DHM-1 and corn syrup + B12in MSM. ↓ = addition of corn syrup; ◊ = addition of B12; ⇩ = reinoculation with DHM-1; WC = water controls, MC + B12=mediacontrol with B12, and AC = autoclaved control with B12. Averages forduplicate bottles are shown. Error bars in panel d represent the datarange; when not visible, the bars are smaller than the symbols.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230812&req=5

Figure 7: Behavior of a mixture of halomethanes in controls (a, b and c) and (d) live bottles with DHM-1 and corn syrup + B12in MSM. ↓ = addition of corn syrup; ◊ = addition of B12; ⇩ = reinoculation with DHM-1; WC = water controls, MC + B12=mediacontrol with B12, and AC = autoclaved control with B12. Averages forduplicate bottles are shown. Error bars in panel d represent the datarange; when not visible, the bars are smaller than the symbols.
Mentions: When CT, CFC-11, and CF (11, 24, and 500 mg/L, respectively) were added at the same time, the pattern of transformation was similar to the two-component mixtures. CT (12 μmol/bottle) transformation was completed first, followed by CFC-11 (57 μmol/bottle) and then CF (456 μmol/bottle) (Figure 7d). One difference between the live treatments shown in Figures 6 and 7d is the pattern of B12 addition. With the two-component mixtures (Figure 6), B12 was added only at the start. With the three-component mixture (Figure 7d), the same molar ratio of B12 was applied, although the additions were timed to coincide with the beginning of transformation of each compound. Accumulation of CS2, DCM, CM, HCFC-21, and HCFC-31 was negligible. Results for controls are shown in Figure 7, panels a, b and c. Nearly complete transformation of CT occurred by day 113 in the media control and AC, versus no significant losses from the WC. Approximately 33% and 11% of CFC-11 was removed in the autoclaved and media controls, respectively, while loss of CFC-11 in WC was minor. Losses of CF in all of the controls were minor. These results demonstrated that transformation of CF was exclusively a biotic process, while abiotic processes contributed to transformation of CT and CFC-11. However, transformation of CT and CFC-11 was considerably faster in the presence of live cells, and DHM-1 was able to achieve complete transformation of a mixture of CT, CFC-11 and CF at high initial concentrations in less than four months in MSM.

Bottom Line: CT (15 mg/L) and CFC-11 (25 mg/L) were also biodegraded without significant accumulation of halomethane daughter products.The highest rate of CF biodegradation occurred at pH 7.7; activity decreased substantially below pH 6.0.Overall, the results suggest that DHM-1 may be effective for bioaugmentation in source zones contaminated with thousands of milligrams per liter of CF and tens of milligrams per liter of CT and CFC-11.

View Article: PubMed Central - HTML - PubMed

Affiliation: PeroxyChem Environmental Solutions (East Asia), Room 5B16, West Wing, Hanwei Plaza, 7 Guanghua Road, Chaoyang District, Beijing 100004, China.

ABSTRACT
A fermentative enrichment culture (designated DHM-1) that grows on corn syrup was evaluated for its ability to cometabolically biodegrade high concentrations of chloroform (CF), carbon tetrachloride (CT), and trichlorofluoromethane (CFC-11). When provided with corn syrup and vitamin B12 (0.03 mol B12 per mol CF), DHM-1 grew and biodegraded up to 2,000 mg/L of CF in 180 days, with only minor transient accumulation of dichloromethane and chloromethane. CT (15 mg/L) and CFC-11 (25 mg/L) were also biodegraded without significant accumulation of halomethane daughter products. The rate of CF biodegradation followed a Michaelis-Menten-like pattern with respect to the B12 concentration; one-half the maximum rate (66 mg CF/L/d) occurred at 0.005 mol B12 per mol CF. DHM-1 was able to biodegrade 500 mg/L of CF at an inoculum level as low as 10(-8) mg protein/L. The highest rate of CF biodegradation occurred at pH 7.7; activity decreased substantially below pH 6.0. DHM-1 biodegraded mixtures of CT, CFC-11, and CF, although CFC-11 inhibited CF biodegradation. Evidence for compete defluorination of CFC-11 was obtained based on a fluoride mass balance. Overall, the results suggest that DHM-1 may be effective for bioaugmentation in source zones contaminated with thousands of milligrams per liter of CF and tens of milligrams per liter of CT and CFC-11.

No MeSH data available.


Related in: MedlinePlus