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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

Impact of pH on biodegradation rates for CF by DHM-1 and the length of the lag phase prior to the onset of biodegradation. Error bars in both directions indicate the 95% confidence interval, based on results from triplicate bottles at each pH.
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Figure 4: Impact of pH on biodegradation rates for CF by DHM-1 and the length of the lag phase prior to the onset of biodegradation. Error bars in both directions indicate the 95% confidence interval, based on results from triplicate bottles at each pH.

Mentions: Maximum CF biodegradation rates for DHM-1 increased with increasing pH from 5.0 to 7.7 (Figure 4). There appeared to be a plateau in the pH range from 6.4 to 7.3, while the rate at pH 7.7 almost doubled relative to that in the circumneutral pH region, reaching 50 mg/L/d. The activity of DHM-1 diminished substantially below pH 6.0 and ceased at pH of 5.0. Lag times (i.e., the time prior to the onset of a maximum rate) decreased as pH increased.


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

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

Impact of pH on biodegradation rates for CF by DHM-1 and the length of the lag phase prior to the onset of biodegradation. Error bars in both directions indicate the 95% confidence interval, based on results from triplicate bottles at each pH.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Impact of pH on biodegradation rates for CF by DHM-1 and the length of the lag phase prior to the onset of biodegradation. Error bars in both directions indicate the 95% confidence interval, based on results from triplicate bottles at each pH.
Mentions: Maximum CF biodegradation rates for DHM-1 increased with increasing pH from 5.0 to 7.7 (Figure 4). There appeared to be a plateau in the pH range from 6.4 to 7.3, while the rate at pH 7.7 almost doubled relative to that in the circumneutral pH region, reaching 50 mg/L/d. The activity of DHM-1 diminished substantially below pH 6.0 and ceased at pH of 5.0. Lag times (i.e., the time prior to the onset of a maximum rate) decreased as pH increased.

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