| 摘要 |
PCT No. PCT/US86/01571 Sec. 371 Date Jun. 2, 1987 Sec. 102(e) Date Jun. 2, 1987 PCT Filed Aug. 1, 1986 PCT Pub. No. WO87/00863 PCT Pub. Date Feb. 12, 1987.An enzyme for conversion of 2,5-diketo-D-gluconate (2,5-DKG) to 2-keto-L-gulonic acid (2-KLG) and a genetically modified organism that expresses all the fermentation enzymes needed to convert glucose to 2-KLG (a precursor to ascorbic acid) using the new enzyme are described. Preferably, the organism is Erwinia citreus, or a mutated strain of Erwinia citreus, unable to use 2,5-DKG or 2-KLG as a sole carbon source, into which the gene for a 2,5-DKG reductase, produced by Corynebacterium sp., SHS 752001, has been inserted. The preferred transformed organism expresses the fermentation enzymes Erwinia citreus normally expresses for fermentation of glucose to 2,5-DKG and, in addition, an enzyme Corynebacterium sp. SHS 752001 expresses for fermentation of 2,5-DKG to 2-KLG. |
