title: Metabolic engineering of Saccharomyces cerevisiae for lactose/whey fermentation.
abstract: Lactose is an interesting carbon source for the production of several bio-products by fermentation, primarily because it is the major component of cheese whey, the main by-product of dairy activities. However, the microorganism more widely used in industrial fermentation processes, the yeast Saccharomyces cerevisiae, does not have a lactose metabolization system. Therefore, several metabolic engineering approaches have been used to construct lactose-consuming S. cerevisiae strains, particularly involving the expression of the lactose genes of the phylogenetically related yeast Kluyveromyces lactis, but also the lactose genes from Escherichia coli and Aspergillus niger, as reviewed here. Due to the existing large amounts of whey, the production of bio-ethanol from lactose by engineered S. cerevisiae has been considered as a possible route for whey surplus. Emphasis is given in the present review on strain improvement for lactose-to-ethanol bioprocesses, namely flocculent yeast strains for continuous high-cell-density systems with enhanced ethanol productivity.
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, Braga, Portugal. luciliad@deb.uminho.pt
authors.forename: Lucília
authors.initials: L
authors.lastname: Domingues
authors.forename: Pedro M R
authors.initials: PM
authors.lastname: Guimarães
authors.forename: Carla
authors.initials: C
authors.lastname: Oliveira
mesh_terms: D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D007785:Lactose / Q000378:metabolism*; D060847:Metabolic Engineering; D008894:Milk Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins; D000431:Ethanol; D007785:Lactose