6533b822fe1ef96bd127d548
RESEARCH PRODUCT
Hydrogen-producingEscherichia colistrains overexpressing lactose permease: FT-IR analysis of the lactose-induced stress
Uldis KalnenieksUldis KalnenieksMarita GavareMarita GavareTalis JuhnaIlze DimantaInese StrazdinaInese StrazdinaMara GrubeMara GrubeJanis Liepinssubject
Lactose permeasebiologyProcess Chemistry and TechnologyMutantBiomedical Engineeringlac operonBioengineeringGeneral MedicineLac repressormedicine.disease_causeApplied Microbiology and Biotechnologylaw.inventionchemistry.chemical_compoundBiochemistrychemistrylawDrug DiscoverymedicineRecombinant DNAAlpha-lactalbuminbiology.proteinMolecular MedicineLactoseEscherichia coliBiotechnologydescription
The lactose permease gene (lacY) was overexpressed in the septuple knockout mutant of Escherichia coli, previously engineered for hydrogen production from glucose. It was expected that raising the lactose transporter activity would elevate the intracellular lactose concentration, inactivate the lactose repressor, induce the lactose operon, and as a result stimulate overall lactose consumption and conversion. However, overexpression of the lactose transporter caused a considerable growth delay in the recombinant strain on lactose, resembling to some extent the "lactose killing" phenomenon. Therefore, the recombinant strain was subjected to selection on lactose-containing media. Selection on plates with 3% lactose yielded a strain with a decreased content of the recombinant plasmid but with an improved ability to grow and produce hydrogen on lactose. Macromolecular analysis of its biomass by means of Fourier transform-infrared spectroscopy demonstrated that increase of the cellular polysaccharide content might contribute to the adaptation of E. coli to lactose stress.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-02-26 | Biotechnology and Applied Biochemistry |