Enhanced production of Aspergillus ficuum endoinulinase in Saccharomyces cerevisiae by using the SUC2-deletion mutation

The inuB gene, encoding an Aspergillus ficuum endoinulinase, was expressed by the Kluyveromyces Marxianus INU1 promoter in Saccharomyces cerevisiae to produce an enzyme free of an exoinulinase and an extracellular invertase. The recombinant yeast strain produced the enzyme at the concentration of 83 .0 U/ml with 2% glucose as a carbon source and 2% fructose as an inducer ad ded after 12 h of initiation of culture. Two Delta suc2 mutants produced hi gher amounts of the enzyme by 13-49 U/ml than SUC2 wild types. The molecula r weight of the secreted enzyme was 67 kDa as measured by SDS-PAGE and West ern blot analysis, which was larger by 1-3 kDa than those of the purified e nzymes. The purified enzyme has been reported to be a mixture of two polype ptides of 64 kDa and 66 kDa in molecular weight. (C) 2001 Elsevier Science Inc. All rights reserved.