Saccharomyces cerevisiae cells secreting an Aspergillus niger beta-galactosidase grow on whey permeate.
We describe the construction of a lactose-utilizing Saccharomyces cerevisiae that expresses the cDNA for a secreted, thermostable beta-galactosidase (lacA) from Aspergillus niger. Yeast cells expressing the lacA gene from the yeast ADH1 promotor on a multicopy plasmid secrete up to 40% of the total beta-galactosidase activity into the growth medium. The secreted product is extensively N-glycosylated, and cells expressing the lacA gene grow on whey permeate (4% w/v lactose) with a doubling time of 1.6 hours. Such strains may offer a solution to the increasing problem of waste whey disposal.
Centre for Biotechnology, Imperial College of Science and Technology, London, U.K.
V
V
Kumar
S
S
Ramakrishnan
T T
TT
Teeri
J K
JK
Knowles
B S
BS
Hartley
D000426:Alcohol Dehydrogenase / Q000235:genetics; D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods; D003470:Culture Media; D004271:DNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D005800:Genes, Fungal; D005822:Genetic Vectors; D007700:Kinetics; D008894:Milk Proteins; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D000067816:Whey Proteins; D001616:beta-Galactosidase / Q000235:genetics* / Q000378:metabolism
D003470:Culture Media; D004271:DNA, Fungal; D008894:Milk Proteins; D011994:Recombinant Proteins; D000067816:Whey Proteins; D000426:Alcohol Dehydrogenase; D001616:beta-Galactosidase