生物
人口
流式细胞术
碘化丙啶
膜透性
膜
色谱法
化学
生物化学
分子生物学
程序性细胞死亡
社会学
人口学
细胞凋亡
作者
Torben Christiansen,Søren Michaelsen,Mogens Wümpelmann,Jens Nielsen
摘要
Abstract The growth and product formation of a Savinase‐producing Bacillus clausii were investigated in high‐cell‐density fed‐batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all feed profiles applied and, in addition, there was a time‐dependent decrease in specific productivity. The specific glucose uptake rate increased with time for constant specific growth rate indicating that the maintenance requirements increased with time, possibly due to a decreasing K + concentration. The physiological state of the cells was monitored during the cultivations using a flow cytometry assay based on the permeability of the cell membrane to propidium iodide. In the latter parts of the fed‐batch cultures with a linear feed profile, a large portion of the cell population was found to have a permeable membrane, indicating a large percentage of dead cells. By assuming that only cells with a nonpermeable membrane contributed to growth and product formation, the physiological properties of this subpopulation were calculated. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 344–352, 2003.
科研通智能强力驱动
Strongly Powered by AbleSci AI