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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

CF biodegradation by DHM-1 in MSM with one dose of B12(at t = 0) and two doses of corn syrup (arrows); WC = water control. Error bars represent the data range for duplicate bottles; when not visible, the bars are smaller than the symbols.
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Figure 2: CF biodegradation by DHM-1 in MSM with one dose of B12(at t = 0) and two doses of corn syrup (arrows); WC = water control. Error bars represent the data range for duplicate bottles; when not visible, the bars are smaller than the symbols.

Mentions: The ability of the DHM-1 enrichment culture to biodegrade CF concentrations above 500 mg/L was evaluated. Approximately 1000 mg/L (i.e., 900 μmol/bottle) was transformed in 85 days and 2000 mg/L (i.e., 1800 μmol/bottle) in 180 days (Figure 2). Accumulation of DCM and CS2 was negligible (<0.5 and 1.0 μmol/bottle, respectively). WC results indicated that diffusive loss of CF was minor. Activity on CF ceased at 4000 mg/L (i.e., 3600 μmol/bottle), which is approximately 50% of the aqueous solubility of CF at 20°C. Growth of DHM-1 on corn syrup, however, was not adversely affected by the high concentrations of CF. Protein concentrations increased to 89, 97 and 128 μg/mL for treatments that received 1000, 2000 and 4000 mg/L of CF, respectively; this is similar to previously reported levels for DHM-1 in the absence of CF, and in the presence of CF at 500 mg/L (Shan et al. [2010a]). Although growth of DHM-1 in the presence of CT or CFC-11 was not monitored, an increase in the turbidity of the MSM a few days after inoculation suggested that DHM-1 also grows on corn syrup in the presence of CT and CFC-11.


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

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

CF biodegradation by DHM-1 in MSM with one dose of B12(at t = 0) and two doses of corn syrup (arrows); WC = water control. Error bars represent the data range for duplicate bottles; 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 2: CF biodegradation by DHM-1 in MSM with one dose of B12(at t = 0) and two doses of corn syrup (arrows); WC = water control. Error bars represent the data range for duplicate bottles; when not visible, the bars are smaller than the symbols.
Mentions: The ability of the DHM-1 enrichment culture to biodegrade CF concentrations above 500 mg/L was evaluated. Approximately 1000 mg/L (i.e., 900 μmol/bottle) was transformed in 85 days and 2000 mg/L (i.e., 1800 μmol/bottle) in 180 days (Figure 2). Accumulation of DCM and CS2 was negligible (<0.5 and 1.0 μmol/bottle, respectively). WC results indicated that diffusive loss of CF was minor. Activity on CF ceased at 4000 mg/L (i.e., 3600 μmol/bottle), which is approximately 50% of the aqueous solubility of CF at 20°C. Growth of DHM-1 on corn syrup, however, was not adversely affected by the high concentrations of CF. Protein concentrations increased to 89, 97 and 128 μg/mL for treatments that received 1000, 2000 and 4000 mg/L of CF, respectively; this is similar to previously reported levels for DHM-1 in the absence of CF, and in the presence of CF at 500 mg/L (Shan et al. [2010a]). Although growth of DHM-1 in the presence of CT or CFC-11 was not monitored, an increase in the turbidity of the MSM a few days after inoculation suggested that DHM-1 also grows on corn syrup in the presence of CT and CFC-11.

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