title: Production of chlorphenesin galactoside by whole cells of β-galactosidase-containing Escherichia coli.
abstract: We investigated the transgalactosylation reaction of chlorphenesin (CPN) using β-galactosidase (β-gal)-containing Escherichia coli (E. coli) cells, in which galactose from lactose was transferred to CPN. The optimal CPN concentration for CPN galactoside (CPN-G) synthesis was observed at 40 mM under the conditions that lactose and β-gal (as E. coli cells) were 400 g/l and 4.8 U/ml, respectively, and the pH and temperature were 7.0 and 40oC, respectively. The time-course profile of CPN-G synthesis under these optimal conditions showed that CPN-G synthesis from 40 mM CPN reached a maximum of about 27 mM at 12 h. This value corresponded to an about 67% conversion of CPN to CPN-G, which was 4.47-5.36-fold higher than values in previous reports. In addition, we demonstrated by thin-layer chromatography to detect the sugar moiety that galactose was mainly transferred from lactose to CPN. Liquid chromatography-mass spectrometry revealed that CPN-G and CPN-GG (CPN galactoside, which accepted two galactose molecules) were definitively identified as the synthesized products using β-gal-containing E. coli cells. In particular, because we did not use purified β-gal, our β-gal-containing E. coli cells might be practical and cost-effective for enzymatically synthesizing CPN-G. It is expected that the use of β-gal-containing E. coli will be extended to galactose derivatization of other drugs to improve their functionality.
authors.affiliation: Department of Biotechnology, Korea National University of Transportation, Jeungpyung, Chungbuk 368-701, Korea.
authors.forename: Sang-Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Hyang-Yeol
authors.initials: HY
authors.lastname: Lee
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Jung
mesh_terms: D001711:Biotransformation; D002743:Chlorphenesin / Q000378:metabolism*; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism*; D005690:Galactose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007785:Lactose / Q000378:metabolism; D013058:Mass Spectrometry; D053858:Metabolic Networks and Pathways; D013696:Temperature; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001616:beta-Galactosidase; D002743:Chlorphenesin; D007785:Lactose; D005690:Galactose