A Novel Parallel Shaken Bioreactor System for Continuous Operation

Akgün, Ali; Maier, B.; Preis, Diana; Roth, Birthe; Klingelhöfer, Renata; Büchs, Jochen

doi:10.1021/bp034289a

Cited by 30 publications

(32 citation statements)

References 14 publications

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“…If derived through anaplerosis, the OAA [1][2][3][4] (where [1][2][3][4] indicates that carbon atoms 1 to 4 of OAA are considered) molecule will have a mass distribution that is a combination of a PEP 1-3 molecule and a CO 2 molecule. If derived through the glyoxylate shunt, half of the molecules will be a combination of pyruvate 2-3 (Pyr 2-3 ) and OAA 1-2 and half a combination of OAA [3][4] and Pyr [2][3] .…”

Section: Methodsmentioning

confidence: 99%

“…If OAA molecules are derived through the TCA cycle, they will have the same mass distribution as a 2-oxoglutarate 2-5 (OGA 2-5 ) fragment. The labeling pattern of OAA [1][2][3][4] can therefore be expressed as follows:…”

Section: Methodsmentioning

confidence: 99%

“…For this purpose, we assumed various degrees of reversibility for this reaction and assessed the quality of the fit for f 1 , f 2 , and the fraction of labeled CO 2 by comparing the measured and calculated mass distribution vectors for OAA [1][2][3][4] . The best solution was always the absence of reversibility.…”

Section: Vol 72 2006 Growth Rate Dependence Of Metabolic Fluxes 1165mentioning

confidence: 99%

“…Small-scale continuous-culture devices, in contrast, are used mostly in evolutionary biology with typical working volumes of 30 to 100 ml (7). A notable exception is the recently developed shake flask system for continuous operation on a 30-to 40-ml scale, which can be used for the determination of microbial growth kinetics and product formation (1).…”

mentioning

confidence: 99%

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Nonlinear Dependency of Intracellular Fluxes on Growth Rate in Miniaturized Continuous Cultures ofEscherichia coli

Nanchen

Schicker

Sauer

2006

Appl Environ Microbiol

144

212

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A novel mini-scale chemostat system was developed for the physiological characterization of 10-ml cultures. The parallel operation of eight such mini-scale chemostats was exploited for systematic 13 C analysis of intracellular fluxes over a broad range of growth rates in glucose-limited Escherichia coli. As expected, physiological variables changed monotonously with the dilution rate, allowing for the assessment of maintenance metabolism. Despite the linear dependence of total cellular carbon influx on dilution rate, the distribution of almost all major fluxes varied nonlinearly with dilution rate. Most prominent were the distinct maximum of glyoxylate shunt activity and the concomitant minimum of tricarboxylic acid cycle activity at low to intermediate dilution rates of 0.05 to 0.2 h ؊1 . During growth on glucose, this glyoxylate shunt activity is best understood from a network perspective as the recently described phosphoenolpyruvate (PEP)-glyoxylate cycle that oxidizes PEP (or pyruvate) to CO 2 . At higher or extremely low dilution rates, in vivo PEP-glyoxylate cycle activity was low or absent. The step increase in pentose phosphate pathway activity at around 0.2 h ؊1 was not related to the cellular demand for the reduction equivalent NADPH, since NADPH formation was 20 to 50% in excess of the anabolic demand at all dilution rates. The results demonstrate that mini-scale continuous cultivation enables quantitative and parallel characterization of intra-and extracellular phenotypes in steady state, thereby greatly reducing workload and costs for stable-isotope experiments.The flexible nature of metabolic networks is based on an extensive set of biochemical reactions whose activity is modulated by complex regulatory networks that operate at multiple levels. The core of this intricate network consists of about 100 central metabolic reactions that synthesize biosynthetic building blocks and regenerate cofactors from a wide variety of substrates. To understand the behavior and regulation of such networks, quantitative data on intracellular fluxes under different conditions and with defined mutants are required. A common problem with mutants, however, is their often dramatic differences in growth rates (2,11,50), such that detected flux differences may be nonspecific, growth rate-related phenomena (4, 29, 46).To ensure highly comparable conditions, continuous cultures are the method of choice because, unlike with batch cultures, a defined steady-state growth rate that equals the externally controlled dilution rate is maintained (17, 31). The labor and cost associated with continuous cultures in controlled bioreactors, however, preclude systematic experiments on any larger scale. For bioprocess development in batch and fed-batch cultures, parallel reactor systems are becoming available (for a recent review, see reference 49), and microtiter plate-based cultivation devices were successfully used for quantitative batch experiments (2, 6, 11, 21, 51). Small-scale continuous-culture devices, in contrast, are used mostly...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Vol 72 2006 Growth Rate Dependence Of Metabolic Fluxes 1165mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Nonlinear Dependency of Intracellular Fluxes on Growth Rate in Miniaturized Continuous Cultures ofEscherichia coli

Nanchen

Schicker

Sauer

2006

Appl Environ Microbiol

144

212

View full text Add to dashboard Cite

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“…Until lately shake flask experiments could be performed only in the batch mode of operation. The COSBIOS device (Continuously Operated Shaking Bioreactor System) introduced by Akgün et al (2004) broadens the field of application to continuous cultures. In continuous cultures under steady-state conditions the environment is well defined and the results obtained are generally more reliable and reproducible Sipkema et al (1998).…”

Section: Introductionmentioning

confidence: 99%

Scale‐up from shake flasks to fermenters in batch and continuous mode with Corynebacterium glutamicum on lactic acid based on oxygen transfer and pH

Seletzky

Noak

Fricke

et al. 2007

Biotech & Bioengineering

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Scale-up from shake flasks to fermenters has been hampered by the lack of knowledge concerning the influence of operating conditions on mass transfer, hydromechanics, and power input. However, in recent years the properties of shake flasks have been described with empirical models. A practical scale-up strategy for everyday use is introduced for the scale-up of aerobic cultures from shake flasks to fermenters in batch and continuous mode. The strategy is based on empirical correlations of the volumetric mass transfer coefficient (k(L) a) and the pH. The accuracy of the empirical k(L) a correlations and the assumptions required to use these correlations for an arbitrary biological medium are discussed. To determine the optimal pH of the culture medium a simple laboratory method based on titration curves of the medium and a mechanistic pH model, which is solely based on the medium composition, is applied. The effectiveness of the scale-up strategy is demonstrated by comparing the behavior of Corynebacterium glutamicum on lactic acid in shake flasks and fermenters in batch and continuous mode. The maximum growth rate (micro(max) = 0.32 h(-1)) and the oxygen substrate coefficient (Y O2 /S= 0.0174 mol/l) of C. glutamicum on lactic acid were equal for shake flask, fermenter, batch, and continuous cultures. The biomass substrate yield was independent of the scale, but was lower in batch cultures (Y(X/S) = 0.36 g/g) than in continuous cultures (Y(X/S) = 0.45 g/g). The experimental data (biomass, respiration, pH) could be described with a simple biological model combined with a mechanistic pH model.

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Biominiaturization of Bioreactors

Hanson

Rao

2010

Encyclopedia of Industrial Biotechnology

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Bioprocess development largely parallels the drug discovery process. Screening a large number of experimental conditions in the early stages, is required. As scales increase through the pilot to the manufacturing stage, process conditions get more stringent in terms of variation. Ideally, one would like the same quality of process information, independent of scale. Traditionally, early stage experiments to optimize growth media and cultivation parameters have been carried out in flasks and liter‐scale bioreactors. This has often resulted in slow development timelines due to a lack of information in the former and the low‐throughput nature of the latter. To circumvent these drawbacks in traditional technologies, much effort has been directed toward developing small‐scale culturing platforms with monitoring and control capabilities that would mimic production conditions. Such systems would enable more experiments to be carried out simultaneously without compromising the quality of information obtained. In this review, traditional as well as novel systems with monitoring and control capabilities are discussed. We have focused on their application in culture and, in many cases, comparison to larger scale systems. Many small‐scale systems have performances comparable to lab‐scale bioreactors. These advances should allow for much more efficient process development as well as impact other areas such as bioprospecting, where hitherto “uncultivable” species may now be grown by screening samples for growth under matrices of conditions that were previously impractical. Another area of impact will be to allow industry to more readily incorporate process analytical technologies.

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A Novel Parallel Shaken Bioreactor System for Continuous Operation

Cited by 30 publications

References 14 publications

Nonlinear Dependency of Intracellular Fluxes on Growth Rate in Miniaturized Continuous Cultures ofEscherichia coli

Nonlinear Dependency of Intracellular Fluxes on Growth Rate in Miniaturized Continuous Cultures ofEscherichia coli

Scale‐up from shake flasks to fermenters in batch and continuous mode with Corynebacterium glutamicum on lactic acid based on oxygen transfer and pH

Biominiaturization of Bioreactors

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