Unesco Chinese Center of Marine Biotechnology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Mar Biotechnol (NY). 2013 Feb;15(1):26-36. doi: 10.1007/s10126-012-9452-5. Epub 2012 May 6.
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.
在这项研究中，一些 ATP-柠檬酸裂解酶基因 (ACL1) 在产脂肪酵母解脂耶罗维亚酵母 SWJ-1b 中被删除，同时异柠檬酸裂解酶基因 (ICL1) 的拷贝数增加，该酵母展示了重组菊粉酶。结果发现，转化子 30 中的脂质含量和异柠檬酸大大减少，柠檬酸产量大大提高。还发现，转化子 30 中的 ACL1 基因表达和 ATP-柠檬酸裂解酶活性下降，而 ICL1 基因表达和异柠檬酸裂解酶活性增强。在 2-L 发酵中，转化子 30 可从 10.0%菊粉中在 214 h 内获得 84.0 g/L 的柠檬酸和 1.8 g/L 的异柠檬酸。结果表明，发酵液中仅残留 0.36%的还原糖和 1.0%的总糖，这表明转化子 30 利用 89.6%的总糖用于柠檬酸生产和细胞生长。
