title: Microbial hexachlorobenzene dechlorination under three reducing conditions.
abstract: The potential dechlorination of hexachlorobenzene (HCB) in medium by 1,2,3-trichlorobenzene (TCB)-adapted mixed culture under three reducing conditions was investigated. It was found that strongest to weakest HCB dechlorination occurred in the order of methanogenic conditions > sulfate-reducing conditions > denitrifying conditions. Under denitrifying conditions, no dechlorination was observed during the first 20 days of incubation. Biotransformation occurred in this order: HCB-->pentachlorobenzene (PCB)-->1,2,3,5-tetrachlorobenzene (TeCB)-->1,3,5-TCB + 1,2,4-TCB-->1,3-dichlorobenzene (DCB), HCB dechlorination was delayed following treatment with ferric chloride and manganese dioxide, but enhanced by the addition of lactate and pyruvate under methanogenic or sulfate-reducing conditions, the addition of acetate had no significant effect on HCB dechlorination under any of the three reducing conditions. Sequential dechlorination was observed at concentrations of 2-50 mg/L, but at a significantly slower rate at the highest concentrations.
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan, Republic of China.
authors.forename: B V
authors.initials: BV
authors.lastname: Chang
authors.forename: C J
authors.initials: CJ
authors.lastname: Su
authors.forename: S Y
authors.initials: SY
authors.lastname: Yuan
mesh_terms: D001673:Biodegradation, Environmental; D002712:Chlorides; D002722:Chlorobenzenes / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005659:Fungicides, Industrial / Q000737:chemistry*; D006581:Hexachlorobenzene / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry; D017014:Methanobacterium; D010087:Oxides / Q000737:chemistry; D016999:Sulfur-Reducing Bacteria
chemical_list: D002712:Chlorides; D002722:Chlorobenzenes; D005290:Ferric Compounds; D005659:Fungicides, Industrial; D017895:Manganese Compounds; D010087:Oxides; C009947:1,2,4-trichlorobenzene; C036720:trichlorobenzene; D006581:Hexachlorobenzene; C042146:1,3-dichlorobenzene; C003060:pentachlorobenzene; C030387:1,2,3,5-tetrachlorobenzene; C016552:manganese dioxide; C024555:ferric chloride