【摘要】 维生素B12广泛应用于医药、食品和畜牧业,主要由微生物发酵得到。脱氮假单胞菌(Pseudomonas denitrificans)和费氏丙酸杆菌(Propionibacterium freudenreichii)是主要的生产菌种。与之相应,维生素B12存在好氧和厌氧2条生物合成途径,生物合成过程十分复杂,2条合成途径大体相同又各有特点。维生素B12发酵产量的提高有待于菌种的改良和发酵工艺的改进。了解维生素B12生物合成途径和代谢调控机制具有重要意义,可为育种工作提供理论基础。更多还原

【Abstract】 Vitamin B_ 12 is widely used for medicine and food additive. Vitamin B_ 12 is produced mainly by fermentation either by an aerobic bacterium, Pseudomonas denitrificans, or an aerotolerant bacterium, Propionibacterium freudenreichii. Biosynthesis of V_ B_ 12 is complex. The aerobic pathways are described and compared in this article. Strain improvement and optimization of fermentation condition is important for V_ B_ 12 production. Elucidation of the biosynthesis and the regulatory mechanisms of the pathway are meaningful for microbial breeding.更多还原