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Fed-batch Production (fed-batch + production)
Selected AbstractsFed-batch production of tetanus toxin by Clostridium tetaniBIOTECHNOLOGY PROGRESS, Issue 1 2010Fernando Fratelli Abstract This study deals with the effects of the initial nitrogen source (NZ Case TT) level and the protocol of glucose addition during the fed-batch production of tetanus toxin by Clostridium tetani. An increase in the initial concentration of NZ Case TT (NZ0) accelerated cell growth, increased the consumption of the nitrogen source as well as the final yield of tetanus toxin, which achieved the highest values (50,60 Lf/mL) for NZ0 , 50 g/L. The addition of glucose at fixed times (16, 56, and 88 h) ensured a toxin yield (,60 Lf/mL) about 33% higher than those of fed-batch runs with addition at fixed concentration (,45 Lf/mL) and about 300% higher than those obtained in reference batch runs nowadays used at industrial scale. The results of this work promise to substantially improve the present production of tetanus toxin and may be adopted for human vaccine production after detoxification and purification. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Enhanced glutathione production by using low-pH stress coupled with cysteine addition in the treatment of high cell density culture of Candida utilisLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2008G. Liang Abstract Aims:, To investigate the effects of pH stress coupled with cysteine addition on glutathione (GSH) production in the treatment of high cell density culture of Candida utilis. Methods and Results:, We have previously observed that most Candida utilis cells remained viable after being subjected to pH at 1·2 for 3 h and that some intracellular GSH leaked into the medium. A cysteine addition strategy was applied in fed-batch production of GSH. A single cysteine addition resulted in higher GSH yield than two separate additions without pH stress. An increase in intracellular GSH content triggered inhibition of ,-glutamylcysteine synthetase (,-GCS). A strategy that combines cysteine addition with low-pH stress was developed to relieve the inhibition of ,-GCS. Conclusion:, Without pH stress, single shot and double shot cysteine addition yielded a total GSH of 1423 and 1325 mg l,1. In comparison, a low-pH stress counterpart resulted in a total GSH of 1542 and 1730 mg l,1, respectively. With low-pH stress, we observed GSH secretion into the medium at 673 and 558 mg l,1 and an increase in the ,-GCS activity by 1·2- and 1·5-fold, respectively. The specific GSH production yield increased from 1·76% to 1·91% (w/w) for single shot, and 1·64% to 2·14% for double shots. Significance and Impact of the Study:, Low-pH shift was applied to alleviate the feedback inhibition of intracellular GSH on ,-GCS activity by secreting GSH into the medium. This strategy is coupled with cysteine addition to enhance GSH production in Candida utilis. [source] Neural Optimization of Fed-batch Streptokinase Fermentation in a Non-ideal BioreactorTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2002Pratap R. PatnaikArticle first published online: 19 MAY 200 Abstract Microbial fermentations involving two or more kinds of competing cells and operating under realistic conditions are difficult to monitor, model and optimize by model-based methods. They deviate from ideal behavior in two significant aspects: incomplete dispersion in the broth and the influx of disturbances. The approach here has been to optimize the filtered noise and dispersion on-line through neural networks. This method has been applied to the fed-batch production of streptokinase (SK). The culture has two kinds of cells , active (or productive) and inactive , and their growth is inhibited by the substrate and the primary metabolite (lactic acid). Using simulated data, the fermentation was optimized by a system of three neural networks, updated continually during successive time intervals. Such sequential optimization with dynamic filtering of inflow noise generated better cell growth and SK activity than static optimization and even an ideal fermentation. Les fermentations microbiennes faisant intervenir deux ou plusieurs sortes de cellules en compétition et se déroulant dans des conditions réelles, sont difficiles à surveiller, à modéliser et à optimiser par des méthodes basées sur des modèles. De telles fermentations s'écartent du comportement idéal dans deux voies importantes : la dispersion incomplète dans le bouillon et la venue de perturbations. Notre approche consiste ici à optimiser le bruit filtré et la dispersion en continu par des réseaux neuronaux. Cette méthode a été appliquée à la production à alimentation discontinue de streptokinase (SK). La culture comporte deux sortes de cellules , actives (ou productives) ou inactives , et leur croissance est inhibée par le substrat et la métabolite primaire (acide lactique). À l'aide de données simulées, la fermentation a été optimisée par un système de trois réseaux neuronaux, qui ont été mis à jour continuellement à des intervalles de temps successifs. Une telle optimisation séquentielle avec filtrage dynamique du bruit génère une meilleure croissance des cellules et activité du SK que l'optimisation statique et même la fermentation idéale. [source] Fed-batch production of tetanus toxin by Clostridium tetaniBIOTECHNOLOGY PROGRESS, Issue 1 2010Fernando Fratelli Abstract This study deals with the effects of the initial nitrogen source (NZ Case TT) level and the protocol of glucose addition during the fed-batch production of tetanus toxin by Clostridium tetani. An increase in the initial concentration of NZ Case TT (NZ0) accelerated cell growth, increased the consumption of the nitrogen source as well as the final yield of tetanus toxin, which achieved the highest values (50,60 Lf/mL) for NZ0 , 50 g/L. The addition of glucose at fixed times (16, 56, and 88 h) ensured a toxin yield (,60 Lf/mL) about 33% higher than those of fed-batch runs with addition at fixed concentration (,45 Lf/mL) and about 300% higher than those obtained in reference batch runs nowadays used at industrial scale. The results of this work promise to substantially improve the present production of tetanus toxin and may be adopted for human vaccine production after detoxification and purification. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] N-linked glycosylation is an important parameter for optimal selection of cell lines producing biopharmaceutical human IgGBIOTECHNOLOGY PROGRESS, Issue 1 2009Patrick H. C. van Berkel Abstract We studied the variations in N-linked glycosylation of human IgG molecules derived from 105 different stable cell lines each expressing one of the six different antibodies. Antibody expression was based on glutamine synthetase selection technology in suspension growing CHO-K1SV cells. The glycans detected on the Fc fragment were mainly of the core-fucosylated complex type containing zero or one galactose and little to no sialic acid. The glycosylation was highly consistent for the same cell line when grown multiple times, indicating the robustness of the production and glycan analysis procedure. However, a twofold to threefold difference was observed in the level of galactosylation and/or non-core-fucosylation between the 105 different cell lines, suggesting clone-to-clone variation. These differences may change the Fc-mediated effector functions by such antibodies. Large variation was also observed in the oligomannose-5 glycan content, which, when present, may lead to undesired rapid clearance of the antibody in vivo. Statistically significant differences were noticed between the various glycan parameters for the six different antibodies, indicating that the variable domains and/or light chain isotype influence Fc glycosylation. The glycosylation altered when batch production in shaker was changed to fed-batch production in bioreactor, but was consistent again when the process was scaled from 400 to 5,000 L. Taken together, the observed clone-to-clone glycosylation variation but batch-to-batch consistency provides a rationale for selection of optimal production cell lines for large-scale manufacturing of biopharmaceutical human IgG. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | ||||||||||