title: Kinetics of the microbial reductive dechlorination of pentachloroaniline.
abstract: 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.
authors.affiliation: School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, USA.
authors.forename: Didem Okutman
authors.initials: DO
authors.lastname: Tas
authors.forename: Ivy N
authors.initials: IN
authors.lastname: Thomson
authors.forename: Frank E
authors.initials: FE
authors.lastname: Löffler
authors.forename: Spyros G
authors.initials: SG
authors.lastname: Pavlostathis
mesh_terms: 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
chemical_list: D000814:Aniline Compounds; D004785:Environmental Pollutants; D002713:Chlorine; C027673:2,3,4,5,6-pentachloroaniline