Kinetics of the microbial reductive dechlorination of pentachloroaniline.
The microbial reductive dechlorination kinetics of pentachloroaniline (PCA) and less chlorinated anilines (CAs) were investigated with a mixed, fermentative/ methanogenic culture. Batch dechlorination assays were performed with all available CAs at an initial concentration of 3 microM, and an incubation temperature of 22 degrees C. Dechlorination of PCA, two tetrachloroanilines (2,3,4,5- and 2,3,5,6-TeCA), five trichloroanilines (2,3,4-, 2,3,5-, 2,4,5-, 2,4,6-, and 3,4,5-TrCA), and one dichloroaniline (3,5-DCA; low extent) was observed but none of the five remaining dichloroanilines and three monochloroanilines were dechlorinated by the enrichment culture during batch assays. The dechlorination rates (k') and half-saturation coefficients (Kc) were measured using nonlinear regression based on the integrated Michaelis-Menten equation under conditions of electron donor saturation and assuming constant biomass concentration over the relatively short batch incubation period. At an initial concentration of CAs of about 3 microM, the values of k' and Kc ranged from 0.25 to 1.19 microM/day and from 0.11 to 1.72 microM, respectively, corresponding to half-lives in the range of 1.5-8.5 days. Model simulations of the sequential dechlorination reactions based on a branched-chain Michaelis-Menten model and using independently measured k' and Kc values matched the experimental data very well.
Tas
Didem Okutman
DO
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, USA.
Thomson
Ivy N
IN
Löffler
Frank E
FE
Pavlostathis
Spyros G
SG
D000814:Aniline Compounds / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D018533:Biomass; D002713:Chlorine / Q000378:metabolism*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity
D000814:Aniline Compounds; D004785:Environmental Pollutants; D002713:Chlorine; C027673:2,3,4,5,6-pentachloroaniline