초록
<P>In this study, some of the ATP-citrate lyase genes (ACL1) were deleted and the copy number of the iso-citrate lyase gene (ICL1) was increased in the marine-derived yeast Yarrowia lipolytica SWJ-1b displaying the recombinant inulinase. It was found that lipid content and iso-citric acid in the transformant 30 obtained were greatly reduced and citric acid production was greatly enhanced. It was also found that the ACL1 gene expression and ATP-citrate lyase activity in the transformant 30 were declined and the ICL1 gene expression and iso-citrate lyase activity were promoted. During the 2-l fermentation, 84.0?g/l of citric acid and 1.8?g/l of iso-citric acid in the fermented medium were attained from 10.0?% of inulin by the transformant 30 within 214?h. The results showed that only 0.36?% of the residual reducing sugar and 1.0?% of the residual total sugar were left in the fermented medium, suggesting that 89.6?% of the total sugar was used for citric acid production and cell growth by the transformant 30.</P>