title: Alcohol production from cheese whey permeate using genetically modified flocculent yeast cells.
abstract: Alcoholic fermentation of cheese whey permeate was investigated using a recombinant flocculating Saccharomyces cerevisiae, expressing the LAC4 (coding for beta-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus enabling for lactose metabolization. Data on yeast fermentation and growth on cheese whey permeate from a Portuguese dairy industry is presented. For cheese whey permeate having a lactose concentration of 50 gL(-1), total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. Using a continuously operating 5.5-L bioreactor, ethanol productivity near 10 g L(-1) h(-1) (corresponding to 0.45 h(-1) dilution rate) was obtained, which raises new perspectives for the economic feasibility of whey alcoholic fermentation. The use of 2-times concentrated cheese whey permeate, corresponding to 100 gL(-1) of lactose concentration, was also considered allowing for obtaining a fermentation product with 5% (w/v) alcohol.
authors.affiliation: Centro de Engenharia Biológica-IBQF, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Domingues
authors.forename: N
authors.initials: N
authors.lastname: Lima
authors.forename: J A
authors.initials: JA
authors.lastname: Teixeira
mesh_terms: D002611:Cheese; D003470:Culture Media; D029968:Escherichia coli Proteins; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D007716:Kluyveromyces / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008894:Milk Proteins / Q000378:metabolism; D009004:Monosaccharide Transport Proteins; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D027981:Symporters
chemical_list: D003470:Culture Media; D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D026901:Membrane Transport Proteins; D008894:Milk Proteins; D009004:Monosaccharide Transport Proteins; D027981:Symporters; D000431:Ethanol; C021499:lactose permease