Effect of substrate concentration on the biotransformation of carbon tetrachloride and 1,1,1-trichloroethane under anaerobic condition

Doong, Ruey‐an; Wu, Shang-Chuen

doi:10.1016/0043-1354(95)00211-1

Cited by 22 publications

(7 citation statements)

References 22 publications

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“…At approximately 8 L/gmol/min, it represents a threefold decrease in maximum specific transformation activity from the nitrate-limiting experiments. This is consistent with the result of Doong and Wu (1996b), who also saw reduced CT transformation rates in cultures provided with lower concentrations of acetate. The effect of using different consortia on the acetate-limited CF yield, however, is less certain.…”

Section: Discussionsupporting

confidence: 93%

Biotransformation of carbon tetrachloride by various acetate- and nitrate-limited denitrifying consortia

Sherwood

Petersen

Skeen

1999

Biotechnol. Bioeng.

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Section: Discussionsupporting

confidence: 93%

Biotransformation of carbon tetrachloride by various acetate- and nitrate-limited denitrifying consortia

Sherwood

Petersen

Skeen

1999

Biotechnol. Bioeng.

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“…This paper describes the complete biological cometabolic transformation of TCA to CA and the conditions necessary for this complete transformation. In general, the rate of cometabolic dechlorination processes increases with an increase in electron donor concentration (Doong and Wu 1996;Wrenn and Rittmann 1996). Here we report that, not only the rate of dechlorination, but also the nature of the products depend on the electron donor concentration.…”

Section: Discussionmentioning

confidence: 61%

Complete transformation of 1,1,1-trichloroethane to chloroethane by a methanogenic mixed population

Best¹,

Hage²,

Doddema³

et al. 1999

Applied Microbiology and Biotechnology

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Complete transformation of 1,1,1-trichloroethane to chloroethane by a methanogenic mixed population de Best, JH; Hage, A; Doddema, HJ; Janssen, DB; Harder, W Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract A methanogenic mixed population in a packed-bed reactor completely transformed 1,1,1-trichloroethane (10 lM) to chloroethane by a cometabolic process. Chloroethane was not further transformed. Acetate and methanol served as electron donors. Complete transformation of 1,1,1-trichloroethane to chloroethane only occurred when sucient electron donor was fed into the reactor. Otherwise, besides chloroethane, 1,1-dichloroethane was also found as a product. The products of 1,1,1-trichloroethane transformation also depended on the type of electron donor present. With acetate, the degree of dechlorination was higher, i.e. more 1,1,1-trichloroethane was transformed to chloroethane than with methanol. In an enrichment culture obtained from the reactor contents, 1,1,1-trichloroethane was only transformed to 1,1-dichloroethane and was not further metabolized. Methanol, acetate, formate, ethanol, 2-propanol, trimethylamine and H 2 , but not dimethylamine and methylamine, served as electron donors for 1,1,1-trichloroethane transformation by this enrichment culture. Both nitrate and nitrite inhibited 1,1,1-trichloroethane transformation; while nitrate completely inhibited 1,1,1-trichloroethane dechlorination, some conversion did occur in the presence of nitrite. The product(s) of this conversion remain unknown, since no chlorinated hydrocarbons were detected.

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“…Benzoate (C 6 H 5 COO − ) and acetate (CH 3 COO − ) were evaluated as primary substrates for inducing the transformation of CT. Benzoate has been shown to be an effective substrate for inducing the anaerobic transformation of perchloroethylene (C 2 Cl 4 ) (Beeman et al 1994) and may ferment to produce hydrogen as a potential electron acceptor for dehalogenation reactions (Yang and McCarty 1998). Conversely, acetate has been used extensively in CT biotransformation studies (Stensel and Dejong 1994; Truex et al 1994; Petersen et al 1994; Doong and Wu 1996, among others). The specific objectives of this study were to (1) evaluate the effect that different primary electron acceptors present in Hanford ground water had on CT transformation; (2) compare the effectiveness of benzoate to that of acetate as the primary substrate driving CT transformation; (3) observe the extent of CF production as a result of CT biotransformation under the different electron donor/acceptor conditions; (4) detect possible problems resulting from microbial stimulation such as flow impediment due to excessive biological growth; (5) evaluate a flow/batch scenario as a means to increase the effective residence time in small‐scale column experiments; and (6) determine spatial variability in CT transformation rates.…”

Section: Introductionmentioning

confidence: 99%

Column Studies of Anaerobic Carbon Tetrachloride Biotransformation with Hanford Aquifer Material

Niemet¹,

Semprini²

2005

Groundwater Monitoring Rem

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Continuous-flow and batch experiments were conducted using a column reactor system containing Hanford Aquifer material in order to assess the potential of in situ bioremediation of carbon tetrachloride (CT) at the Hanford site in southcentral Washington state. Benzoate and acetate were evaluated as primary substrates both in the presence and absence of nitrate as a potential electron acceptor. Each of the four resulting test conditions was first run under continuous-flow mode until a pseudo-steady state was achieved and then switched to batch mode. The longer residence time of the batch portion of the test resulted in more complete transformations and helped elucidate zones of variable activity within the column. Reductions in CT concentration and chloroform (CF) production were observed in all test conditions. Benzoate generally supported faster and more complete CT transformations than acetate, even though substrate use and denitrification was more rapid for acetate. Sulfate was present in all cases; yet, sulfate reduction was never observed, even during extended absences of nitrate and nitrite. CT transformation was most rapid near the point of injection, with rates decreasing toward the effluent end of the column. These results indicate that the microbial population at Hanford is capable of transforming CT in the subsurface. However, methods to control the production of CF may be necessary before this technology can be successfully implemented in the field.

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Effect of substrate concentration on the biotransformation of carbon tetrachloride and 1,1,1-trichloroethane under anaerobic condition

Cited by 22 publications

References 22 publications

Biotransformation of carbon tetrachloride by various acetate- and nitrate-limited denitrifying consortia

Biotransformation of carbon tetrachloride by various acetate- and nitrate-limited denitrifying consortia

Complete transformation of 1,1,1-trichloroethane to chloroethane by a methanogenic mixed population

Column Studies of Anaerobic Carbon Tetrachloride Biotransformation with Hanford Aquifer Material

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