title: Use of a genetically engineered Escherichia coli strain to produce 1,2-dihydroxy-4'-chlorobiphenyl.
abstract: Genetically engineered kanamycin-resistant Escherichia coli HB101 containing the mutant chimeric plasmid pAW6194-T17 specifying biphenyl dioxygenase and dihydrodiol dehydrogenase and lacking the ability to produce active 3-phenylcatechol dioxygenase was used to produce 1,2-dihydroxy-4'-chlorobiphenyl (DHCB) from 4-chlorobiphenyl. Resting-cell suspensions of genetically engineered E. coli in mineral salts medium (pH 7.0) containing 880 microM 4-chlorobiphenyl produced 110 microM DHCB. The Km for 4-chlorobiphenyl was 3.3 mM. Biotransformation of DHCB from 4-chlorobiphenyl was maximum when cells (2.5 mg of protein per ml) were incubated with shaking (150 rpm) at pH 7.0 and 30 degrees C for 6 h. The enzymatically produced DHCB was a suitable substrate for assaying 3-phenylcatechol dioxygenase activity. Biologically produced DHCB showed UV and mass spectra similar to those of chemically synthesized DHCB. The bioconversion rate of ortho-substituted chlorobiphenyl was slower than that of the para- or meta-substituted chlorobiphenyl.
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, Michigan 48309-4401.
authors.forename: A A
authors.initials: AA
authors.lastname: Khan
authors.forename: S K
authors.initials: SK
authors.lastname: Walia
mesh_terms: D001711:Biotransformation; D001713:Biphenyl Compounds / Q000737:chemistry / Q000378:metabolism*; D002396:Catechols / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005285:Fermentation; D005818:Genetic Engineering; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013058:Mass Spectrometry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D001713:Biphenyl Compounds; D002396:Catechols; C074625:1,2-dihydroxy-4'-chlorobiphenyl; C006983:4-chlorobiphenyl