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Characteristics of Saccharomyces cerevisiae gal1 Δ and gal1 Δ hxk2 Δ mutants expressing recombinant proteins from the GAL promoter
Author(s) -
Ah Kang Hyun,
Kyu Kang Woo,
Go SuMin,
Rezaee Abbas,
Hari Krishna Sajja,
Ki Rhee Sang,
Kim JeongYoon
Publication year - 2005
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20240
Subject(s) - saccharomyces cerevisiae , recombinant dna , heterologous , mutant , strain (injury) , biochemistry , delta , chemistry , galactose , biology , microbiology and biotechnology , yeast , gene , anatomy , engineering , aerospace engineering
Galactose can be used not only as an inducer of the GAL promoters, but also as a carbon source by Saccharomyces cerevisiae , which makes recombinant fermentation processes that use GAL promoters complicated and expensive. To overcome this problem during the cultivation of the recombinant strain expressing human serum albumin (HSA) from the GAL10 promoter, a gal1 Δ mutant strain was constructed and its induction kinetics investigated. As expected, the gal1 Δ strain did not use galactose, and showed high levels of HSA expression, even at extremely low galactose concentrations (0.05–0.1 g/L). However, the gal1 Δ strain produced much more ethanol, in a complex medium containing glucose, than the GAL1 strain. To improve the physiological properties of the gal1 Δ mutant strain as a host for heterologous protein production, a null mutation of either MIG1 or HXK2 was introduced into the gal1 Δ mutant strain, generating gal1 Δ mig1 Δ and gal1 Δ hxk2 Δ double strains. The gal1 Δ hxk2 Δ strain showed a decreased rate of ethanol synthesis, with an accelerated rate of ethanol consumption, compared to the gal1 Δ strain, whereas the gal1 Δ mig1 Δ strain showed similar patterns to the gal1 Δ strain. Furthermore, the gal1 Δ hxk2 Δ strain secreted much more recombinant proteins (HSA and HSA fusion proteins) than the other strains. The results suggest that the gal1 Δ hxk2 Δ strain would be useful for the large‐scale production of heterologous proteins from the GAL10 promoter in S. cerevisiae. © 2005 Wiley Periodicals, Inc.