Park Yong-Cheol, Kim Sung-Gun, Park Kyungmoon, Lee Kelvin H, Seo Jin-Ho
Interdisciplinary Program for Biochemical Engineering and Biotechnology, School of Agricultural Biotechnology, Seoul National University, Seoul, 151-742, Korea.
Appl Microbiol Biotechnol. 2004 Dec;66(3):297-302. doi: 10.1007/s00253-004-1678-3.
D-ribose, a five-carbon sugar, is used as a key intermediate for the production of various biomaterials, such as riboflavin and inosine monophosphate. A high D-ribose-producing Bacillus subtilis SPK1 strain was constructed by the chemical mutation of the transketolase-deficient strain, B. subtilis JY1. Batch fermentation of B. subtilis SPK1 with 20 g l(-1) xylose and 20 g l(-1) glucose resulted in 4.78 g l(-1) dry cell mass, 23.0 g l(-1) D-ribose concentration, and 0.72 g l(-1) h(-1) productivity, corresponding to a 1.5- to 1.7-fold increase when compared with values for the parental strain. A late-exponential phase was chosen as the best point for switching to a fed-batch process. Optimized fed-batch fermentation of B. subtilis SPK1, feeding a mixture of 200 g l(-1) xylose and 50 g l(-1) glucose after the late-exponential phase reduced the residual xylose and glucose concentrations to less than 7.0 g l(-1) and gave the best results of 46.6 g l(-1) D-ribose concentration and 0.88 g l(-1) h(-1) productivity which were 2.0- and 1.2-fold higher than the corresponding values in a simple batch fermentation.
D -核糖是一种五碳糖，用作生产各种生物材料（如核黄素和肌苷一磷酸）的关键中间体。通过对转酮醇酶缺陷型菌株枯草芽孢杆菌JY1进行化学诱变，构建了高产D -核糖的枯草芽孢杆菌SPK1菌株。用20 g l(-1)木糖和20 g l(-1)葡萄糖对枯草芽孢杆菌SPK1进行分批发酵，得到4.78 g l(-1)的干细胞质量、23.0 g l(-1)的D -核糖浓度和0.72 g l(-1) h(-1)的生产率，与亲本菌株的值相比提高了1.5至1.7倍。选择指数后期作为切换到补料分批培养过程的最佳时间点。对枯草芽孢杆菌SPK1进行优化补料分批发酵，在指数后期加入200 g l(-1)木糖和50 g l(-1)葡萄糖的混合物，将残留木糖和葡萄糖浓度降低到7.0 g l(-1)以下，得到了最佳结果，D -核糖浓度为46.6 g l(-1)，生产率为0.88 g l(-1) h(-1)，分别比简单分批发酵中的相应值高2.0倍和1.2倍。
