Ethanol production from inulin and unsterilized meal of Jerusalem artichoke tubers by Saccharomyces sp. W0 expressing the endo-inulinase gene from Arthrobacter sp.

After the endo-inulinase gene from Arthrobacter sp. was ligated the expression vectors pMIDSC31 and pMIRSC31, the endo-inulinase gene was inserted into the chromosomal DNA of Saccharomyces sp. W0. It was found that the inulinase activity of the recombinant yeast D5 in which the endo-inulinase gene was inserted into the delta sequence was higher than that of the recombinant yeast R1 in which the endo-inulinase gene was inserted into 18S rDNA sequence. More ethanol from inulin was produced by the recombinant yeast D5 than by the recombinant yeast R1. But Saccharomyces sp. W0 produced the lowest inulinase activity and concentration of ethanol. During the 3-l fermentation, the recombinant yeast D5 could produce 13.6 ml of ethanol per 100ml of the fermented medium from 30% inulin. The recombinant yeast D5 could actively convert the unsterilized meal of Jerusalem artichoke tubers, yielding 10.1 ml of ethanol per 100ml of the fermented medium.