title: Biodegradation of hexachlorobenzene by a constructed microbial consortium.
abstract: A consortium comprised of an engineered Escherichia coli DH5α and a natural pentachlorophenol (PCP) degrader, Sphingobium chlorophenolicum ATCC 39723, was assembled for degradation of hexachlorobenzene (HCB), a persistent organic pollutant. The engineered E. coli strain, harbouring a gene cassette (camA (+) camB (+) camC) that encodes the F87W/Y96F/L244A/V247L mutant of cytochrome P-450cam (CYP101), oxidised HCB to PCP. The resulting PCP was then further completely degraded by ATCC 39723. The results showed that almost 40 % of 4 μM HCB was degraded by the consortium at a rate of 0.033 nmol/mg (dry weight)/h over 24 h, accompanied by transient accumulation and immediate consumption of the intermediate PCP, detected by gas chromatography. In contrast, in the consortium comprised of Pseudomonas putida PaW340 harbouring camA (+) camB (+) camC and ATCC 39723, PCP accumulated in PaW340 cells but could not be further degraded, which may be due to a permeability barrier of Pseudomonas PaW340 for PCP transportation. The strategy of bacterial co-culture may provide an alternative approach for the bioremediation of HCB contamination.
authors.affiliation: School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, 68 Xuefu South Road, Changqing Garden, Wuhan, 430023, Hubei, China, yandz6808@163.com.
authors.forename: Da-Zhong
authors.initials: DZ
authors.lastname: Yan
authors.forename: Ling-Qi
authors.initials: LQ
authors.lastname: Mao
authors.forename: Cun-Zhi
authors.initials: CZ
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
mesh_terms: D001673:Biodegradation, Environmental; D019475:Camphor 5-Monooxygenase / Q000235:genetics* / Q000378:metabolism; D002849:Chromatography, Gas; D018920:Coculture Techniques; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005818:Genetic Engineering; D006581:Hexachlorobenzene / Q000378:metabolism*; D059013:Microbial Consortia; D009154:Mutation; D010416:Pentachlorophenol / Q000378:metabolism*; D042301:Sphingomonadaceae / Q000378:metabolism*
chemical_list: D006581:Hexachlorobenzene; D010416:Pentachlorophenol; D019475:Camphor 5-Monooxygenase