Abstract
Abstract Inulin and inulin-containing materials are good substrates for bioethanol production. In order to construct genetically stable recombinant yeast cells carrying the inulinase gene for bioethanol production from inulin, a new 18S rDNA integration vector was constructed in this study. After the INU1 gene encoding exo-inulinase was ligated into the 18S rDNA integration vector, transformed into uracil mutant of Saccharomyces sp. W0 and integrated into its chromosomes, the transformant MguINU1-04 obtained could produce 34.8 U cm −3 of inulinase activity within 72 h. The transformant could stably produce high activity of inulinase after five sequential batch cultivations. During 5-l fermentation, ethanol concentration in the fermentation medium containing 30.0% inulin was 14.7% (v/v) and the ethanol productivity was over 0.386 g of ethanol per g of inulin. When the tuber meal of Jerusalem artichoke (50.0%) was fermented into ethanol by the transformant MguINU1-04, 12.6% (v/v) ethanol was produced within 120 h and the ethanol productivity was over 0.331 g of ethanol per g of sugar. Therefore, inulin and inulin in the tuber meal of Jerusalem artichoke could be directly converted into high concentrations of ethanol by the engineered Saccharomyces sp. W0 carrying the inulinase gene.
Published Version
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