Li J K, Asali E C, Humphrey A E, Horvath J J
Center for Molecular Bioscience and Biotechnology, Lehigh University, Bethlehem, Pennsylvania 18015.
Biotechnol Prog. 1991 Jan-Feb;7(1):21-7. doi: 10.1021/bp00007a004.
Four key cellular metabolic fluorophores--tryptophan, pyridoxine, NAD(P)H, and riboflavin--were monitored on-line by a multiple excitation fluorometric system (MEFS) and a modified SLM 8000C scanning spectrofluorometer in three model yeast fermentation systems--bakers' yeast growing on glucose, Candida utilis growing on ethanol, and Saccharomyces cerevisiae RTY110/pRB58 growing on glucose. The measured fluorescence signals were compared with cell concentration, protein concentration, and cellular activity. The results indicate that the behavior and fluorescence intensity of various fluorophores differ in the various fermentation systems. Tryptophan fluorescence is the best signal for the monitoring of cell concentration in bakers' yeast and C. utilis fermentations. Pyridoxine fluoresce is the best signal for the monitoring of cell concentration in the S. cerevisiae RTY110/pRB58 fermentation. In bakers' yeast fermentations the pyridoxine fluorescence signal can be used to monitor cellular activity. The NAD(P)H fluorescence signal is a good indicator of cellular activity in the C. utilis fermentation. For this fermentation NAD(P)H fluorescence can be used to control ethanol feeding in a fed-batch process.
通过多激发荧光系统（MEFS）和改良的SLM 8000C扫描荧光分光光度计，在线监测了三种酵母发酵模型系统（在葡萄糖上生长的面包酵母、在乙醇上生长的产朊假丝酵母以及在葡萄糖上生长的酿酒酵母RTY110/pRB58）中的四种关键细胞代谢荧光团——色氨酸、吡哆醇、NAD(P)H和核黄素。将测得的荧光信号与细胞浓度、蛋白质浓度和细胞活性进行了比较。结果表明，不同发酵系统中各种荧光团的行为和荧光强度有所不同。色氨酸荧光是监测面包酵母和产朊假丝酵母发酵中细胞浓度的最佳信号。吡哆醇荧光是监测酿酒酵母RTY110/pRB58发酵中细胞浓度的最佳信号。在面包酵母发酵中，吡哆醇荧光信号可用于监测细胞活性。NAD(P)H荧光信号是产朊假丝酵母发酵中细胞活性的良好指标。对于这种发酵，NAD(P)H荧光可用于控制分批补料过程中的乙醇进料。
