title: Improvement in organic solvent tolerance by double disruptions of proV and marR genes in Escherichia coli.
abstract: OBJECTIVE
  To investigate the involvement of osmoprotectant transporters in organic solvent tolerance in Escherichia coli and to construct an E. coli strain with high organic solvent tolerance.
  
  
  RESULTS
  The organic solvent tolerance of ΔbetT, ΔproV, ΔproP or ΔputP single-gene knockout mutants of E. coli K-12 strain was examined. Among these mutants, the organic solvent tolerance of the ΔproV mutant remarkably increased compared with that of the parent strain. It has been known that a marR mutation confers tolerance on E. coli to organic solvents. A ΔproV and ΔmarR double-gene mutant was more tolerant to organic solvents than the ΔproV or ΔmarR single-gene mutant. The n-hexane amount accumulated in E. coli cells was examined after incubation in an n-hexane-aqueous medium two-phase system. The intracellular n-hexane level in the ΔproV and ΔmarR double-gene mutant was kept lower than those of the parent strain, ΔproV mutant and ΔmarR mutant.
  
  
  CONCLUSIONS
  The organic solvent tolerance level in E. coli highly increased by dual disruption of proV and marR.
  
  
  CONCLUSIONS
  This study suggests a new strategy for increasing the organic solvent tolerance level in E. coli to improve the usability of the whole-cell biocatalysts in two-phase systems employing organic solvents.
authors.affiliation: Bio-Nano Electronic Research Center, Toyo University, Kawagoe, Saitama, Japan. dokyu@toyo.jp
authors.forename: N
authors.initials: N
authors.lastname: Doukyu
authors.forename: K
authors.initials: K
authors.lastname: Ishikawa
authors.forename: R
authors.initials: R
authors.lastname: Watanabe
authors.forename: H
authors.initials: H
authors.lastname: Ogino
mesh_terms: D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D055786:Gene Knockout Techniques; D005798:Genes, Bacterial; D006586:Hexanes / Q000494:pharmacology*; D008074:Lipoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D033902:Periplasmic Binding Proteins / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D012997:Solvents / Q000494:pharmacology*
chemical_list: C083497:AcrA protein, E coli; D029968:Escherichia coli Proteins; D006586:Hexanes; D008074:Lipoproteins; C080004:MarR protein, E coli; D026901:Membrane Transport Proteins; C053437:PROX protein, E coli; D033902:Periplasmic Binding Proteins; D012097:Repressor Proteins; D012997:Solvents; C026385:n-hexane