The effect of the electric field on lag phase, β-galactosidase production and plasmid stability of a recombinant saccharomyces cerevisiae strain growing on lactose

Inês Castro, Carla Oliveira, Lucília Domingues, José A. Teixeira, António A. Vicente

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Ethanol and β-galactosidase production from cheese whey may significantly contribute to minimise environmental problems while producing value from low-cost raw materials. In this work, the recombinant Saccharomyces cerevisiae NCYC869-A3/pVK1. 1 flocculent strain expressing the lacA gene (coding for β-galactosidase) of Aspergillus niger under ADHI promoter and terminator was used. This strain shows high ethanol and β-galactosidase productivities when grown on lactose. Batch cultures were performed using SSlactose medium with 50 g L -1 lactose in a 2-L bioreactor under aerobic and microaerophilic conditions. Temperature was maintained at 30 °C and pH 4. 0. In order to determine the effect of an electric field in the fermentation profile, titanium electrodes were placed inside the bioreactor and different electric field values (from 0. 5 to 2 V cm -1) were applied. For all experiments, β-galactosidase activity, biomass, protein, lactose, glucose, galactose and ethanol concentrations were measured. Finally, lag phase duration and specific growth rate were calculated. Significant changes in lag phase duration and biomass yield were found when using 2 V cm -1. Results show that the electric field enhances the early stages of fermentation kinetics, thus indicating that its application may improve industrial fermentations' productivity. The increase in electric field intensity led to plasmid instability thus decreasing β-galactosidase production.
Original languageEnglish
Pages (from-to)3014-3020
Number of pages7
JournalFood and Bioprocess Technology
Volume5
Issue number8
DOIs
Publication statusPublished - Nov 2012
Externally publishedYes

Keywords

  • β-galactosidase
  • Electric field
  • Growth parameters
  • Plasmid stability
  • Recombinant S. cerevisiae strain

Fingerprint

Dive into the research topics of 'The effect of the electric field on lag phase, β-galactosidase production and plasmid stability of a recombinant saccharomyces cerevisiae strain growing on lactose'. Together they form a unique fingerprint.

Cite this