Kim T J, Lee Y D, Kim H S
Department of Biotechnology, Korea Advanced Institute of Science and Technology, Yusung-Gu, Taejon 305-701, Korea.
Biotechnol Bioeng. 1993 Jan 5;41(1):88-94. doi: 10.1002/bit.260410112.
Cyclodextrin glycosyltransferase (CGTase) was found to be severely inhibited by cyclodextrins. In order to increase the conversion yield by reducing product inhibition and reuse the CGTase in the production of cyclodextrins from milled corn starch, an ultrafiltration membrane bioreactor system was employed. In a batch operation with ultrafiltration, the conversion yield was increased 57% compared with that without ultrafiltration. Operating conditions for the continuous production of cyclodextrins in the membrane bioreactor were optimized by taking into consideration the filtration rate and the conversion yield as follows: initial starch concentration, 7% (w/v); starch feeding rate, 240 mg/h; CGTase loading, 350 units/initial gram starch. When cyclodextrins were continuously produced in the membrane bioreactor under optimized conditions, 340 units of CGTase was require to produce 1 g of cyclodextrins for 48 h, while in the case of conventional batch operation, 1 g of cyclodextrins was produced for 24 h by 1410 units of CGTase.
人们发现环糊精糖基转移酶（CGTase）会受到环糊精的严重抑制。为了通过减少产物抑制来提高转化率，并在以磨碎玉米淀粉生产环糊精的过程中重复使用CGTase，采用了超滤膜生物反应器系统。在超滤的间歇操作中，转化率比未进行超滤时提高了57%。通过考虑过滤速率和转化率，对膜生物反应器中环糊精连续生产的操作条件进行了如下优化：初始淀粉浓度为7%（w/v）；淀粉进料速率为240 mg/h；CGTase负载量为350单位/初始克淀粉。在优化条件下于膜生物反应器中连续生产环糊精时，生产1克环糊精48小时需要340单位的CGTase，而在传统间歇操作的情况下，生产1克环糊精24小时需要1410单位的CGTase。
