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

AMB Express (2014-11-18)
Huifeng Shan, Han Wang, Rong Yu, Priya Jacob, David L Freedman
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.

MATERIALS
Product Number
Brand
Product Description

Supelco
Dichloromethane solution, contains 10 % (v/v) methanol
Sigma-Aldrich
Carbon nanofibers, graphitized (iron-free), composed of conical platelets, D × L 100 nm × 20-200 μm
Sigma-Aldrich
Carbon nanofibers, graphitized, platelets(conical), >98% carbon basis, D × L 100 nm × 20-200 μm
Sigma-Aldrich
Carbon nanofibers, pyrolitically stripped, platelets(conical), >98% carbon basis, D × L 100 nm × 20-200 μm
Carbon - Vitreous, foam, 275x330mm, 0.05g.cmué, porosity 96.5%, 24 pores/cm
Carbon - Vitreous, foil, 8x8mm, thickness 0.5mm, glassy carbon
Carbon - Vitreous, tube, 100mm, outside diameter 10mm, inside diameter 3mm, wall thickness 3.5mm, glassy carbon
Carbon - Vitreous, tube, 50mm, outside diameter 10mm, inside diameter 3mm, wall thickness 3.5mm, glassy carbon
Carbon - Vitreous, foil, 50x50mm, thickness 1.0mm, glassy carbon
Carbon - Vitreous, foam, 300x300mm, thickness 30mm, bulk density 0.05g/cm3, porosity 96.5%
Carbon - Vitreous, foam, 150x150mm, 0.05g.cmué, porosity 96.5%, 24 pores/cm
Carbon - Vitreous, foil, 100x100mm, thickness 1.0mm, glassy carbon
Carbon - Vitreous, rod, 200mm, diameter 10mm, glassy carbon
Carbon - Vitreous, foil, 100x100mm, thickness 6.0mm, glassy carbon
Carbon - Vitreous, foil, 25x25mm, thickness 0.5mm, glassy carbon
Carbon - Vitreous, foil, 50x50mm, thickness 4.0mm, glassy carbon
Carbon - Vitreous, rod, 100mm, diameter 3.0mm, glassy carbon
Carbon - Vitreous, rod, 200mm, diameter 3.0mm, glassy carbon
Carbon - Vitreous, foil, 25x25mm, thickness 4.0mm, glassy carbon
Carbon - Vitreous, foam, 150x150mm, thickness 3.2mm, bulk density 0.05g/cm3, porosity 96.5%
Carbon - Vitreous, rod, 200mm, diameter 5.0mm, glassy carbon
Carbon - Vitreous, rod, 200mm, diameter 7.0mm, glassy carbon
Carbon - Vitreous, foil, 10x10mm, thickness 4.0mm, glassy carbon
Carbon - Vitreous, foil, 10x10mm, thickness 1.0mm, glassy carbon
Carbon - Vitreous, rod, 50mm, diameter 1.0mm, glassy carbon
Carbon - Vitreous, rod, 100mm, diameter 1.0mm, glassy carbon
Carbon - Vitreous, foam, 275x330mm, thickness 3.2mm, bulk density 0.05g/cm3, porosity 96.5%
Carbon - Vitreous, rod, 200mm, diameter 1.0mm, glassy carbon
Carbon - Vitreous, rod, 100mm, diameter 5.0mm, glassy carbon
Carbon - Vitreous, foil, 100x100mm, thickness 2.0mm, glassy carbon