Characterisation of the gas–liquid mass transfer in shaking bioreactors

Maier, Ulrike; Büchs, Jochen

doi:10.1016/s1369-703x(00)00107-8

Cited by 210 publications

(150 citation statements)

References 10 publications

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“…) in the biological system at a culture volume of 0.5 ml is similar to that in 250-ml Erlenmeyer flasks filled with 25 ml of medium under identical shaking conditions (40 mmol liter Ϫ1 h Ϫ1 [15]). By applying methods developed for the evaluation of the mass transfer resistance of the sterile plug in shaking flasks (10,16), the minimum concentration in the headspace of the wells (representing the mass transfer resistance of our lid) was estimated.…”

mentioning

confidence: 95%

Methods for Intense Aeration, Growth, Storage, and Replication of Bacterial Strains in Microtiter Plates

Duetz

Rüedi

Hermann

et al. 2000

Appl Environ Microbiol

317

259

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Miniaturized growth systems for heterogeneous culture collections are not only attractive in reducing demands for incubation space and medium but also in making the parallel handling of large numbers of strains more practicable. We report here on the optimization of oxygen transfer rates in deep-well microtiter plates and the development of a replication system allowing the simultaneous and reproducible sampling of 96 frozen glycerol stock cultures while the remaining culture volume remains frozen. Oxygen transfer rates were derived from growth curves of Pseudomonas putida and from rates of oxygen disappearance due to the cobalt-catalyzed oxidation of sulfite. Maximum oxygen transfer rates (38 mmol liter ؊1 h ؊1 , corresponding to a mass transfer coefficient of 188 h ؊1 ) were measured during orbital shaking at 300 rpm at a shaking diameter of 5 cm and a culture volume of 0.5 ml. A shaking diameter of 2.5 cm resulted in threefold-lower values. These high oxygen transfer rates allowed P. putida to reach a cell density of approximately 9 g (dry weight) liter ؊1 during growth on a glucose mineral medium at culture volumes of up to 1 ml. The growth-and-replication system was evaluated for a culture collection consisting of aerobic strains, mainly from the genera Pseudomonas, Rhodococcus, and Alcaligenes, using mineral media and rich media. Cross-contamination and excessive evaporation during vigorous aeration were adequately prevented by the use of a sandwich cover of spongy silicone and cotton wool on top of the microtiter plates.The general practice during screening of large microbial strain collections for new enzyme activities or bioactive compounds is that each strain is handled individually. The labor and time involved in separately reviving the stock cultures on agar plates and the subsequent inoculation of tubes or Erlenmeyer flasks are major limiting factors in the progress of such screening projects. This bottleneck might be alleviated if large numbers of microbial strains could be handled in parallel rather than in sequence, preferably in a format that is compatible with current standards in the manipulation of large numbers of liquid samples, e.g., in 96-or 384-well microtiter plates.Until now, the use of microtiter plates for the growth and maintenance of microbial strains has been mainly limited to clonal libraries in Escherichia coli (9,11,20) and yeasts (2, 18). For this purpose, the apparent drawbacks of growth in microtiter plates-low aeration rates and small working volumesare generally less relevant since E. coli and yeasts can grow anaerobically. Furthermore, small amounts of biomass generally suffice as the use of high-copy-number vectors ensures high levels of the desired gene or gene product. The resulting mixed aerobic-anaerobic growth, however, can lead to undesirable variations in biomass levels from well to well, especially since oxygen diffusion rates for an individual well may be affected by its position in the microtiter plate. Such well-to-well variations are especially troublesome in...

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confidence: 95%

Methods for Intense Aeration, Growth, Storage, and Replication of Bacterial Strains in Microtiter Plates

Duetz

Rüedi

Hermann

et al. 2000

Appl Environ Microbiol

317

259

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“…Using a simple model we simulated the oxygen dynamics within the culture setup where only diffusion and respiration rates were taken into account. The diffusion model is formulated as an equation of gas transfer (Maier and Büchs, 2001) from the headspace into the liquid phase (culture medium, where oxygen flux diffusion is proportional to oxygen saturation and concentration and where we experimentally estimated the diffusion rate to be 0.18 h −1 ). Using the oxygraph based respiration rates (0.25 mM O 2 h −1 ) we estimated that cultures should be oxygen depleted after 1 h (data not shown).…”

Section: Respiration Rates Dynamicsmentioning

confidence: 99%

Increased bacterial growth efficiency with environmental variability: results from DOC degradation by bacteria in pure culture experiments

Eichinger¹,

Sempéré²,

Grégori³

et al. 2010

Biogeosciences

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Abstract. This paper assesses how considering variation in DOC availability and cell maintenance in bacterial models affects Bacterial Growth Efficiency (BGE) estimations. For this purpose, we conducted two biodegradation experiments simultaneously. In experiment one, a given amount of substrate was added to the culture at the start of the experiment whilst in experiment two, the same amount of substrate was added, but using periodic pulses over the time course of the experiment. Three bacterial models, with different levels of complexity, (the Monod, Marr-Pirt and the dynamic energy budget -DEB -models), were used and calibrated using the above experiments. BGE has been estimated using the experimental values obtained from discrete samples and from model generated data. Cell maintenance was derived experimentally, from respiration rate measurements. The results showed that the Monod model did not reproduce the experimental data accurately, whereas the Marr-Pirt and DEB models demonstrated a good level of reproducibility, probably because cell maintenance was built into their formula. Whatever estimation method was used, the BGE value was always higher in experiment two (the periodically pulsed substrate) as compared to the initially one-pulsed-substrate experiment. Moreover, BGE values estimated without considering cell maintenance (Monod model and empirical formula) were always smaller than BGE values obtained from models taking cell maintenance into account. Since BGE is commonly estimated using constant experimental systems and ignoreCorrespondence to: R. Sempéré (richard.sempere@univmed.fr) maintenance, we conclude that these typical methods underestimate BGE values. On a larger scale, and for biogeochemical cycles, this would lead to the conclusion that, for a given DOC supply rate and a given DOC consumption rate, these BGE estimation methods overestimate the role of bacterioplankton as CO 2 producers.

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“…Models for plug resistance can be found in the literature [19], [20]. OTR in shaking bioreactors was studied by Maier et al [20], [21]. Oxygen limitation is considered by Büchs [4] as a phenomenon in shake flasks, which should be avoided.…”

Section: Introductionmentioning

confidence: 99%

Novel dynamic model for aerated shaking bioreactors

Tabrizi

Amoabediny

Moshiri

et al. 2011

Biotech and App Biochem

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Abstract.A novel mathematical model of aerated shaking bioreactors is developed and its accuracy is evaluated with experimental data. Corynebacterium glutamicum (DM 1730) and Arxula adeninivorans (WT LS3) are used as model microorganisms. In order to get the experimental data, shake flasks of 250 mL and filling volume of 15 mL, together with online measurement tools for measuring oxygen transfer rate and tools for measuring dry biomass concentration, are used. This mathematical model may be regarded as a key tool for computational simulations or developing model-based control approaches for necessary automation and optimization purposes. Moreover, the error evaluation presented in this paper should be taken into account when using the model. The squared Pearson product-moment correlation coefficient (r 2 ) and average deviation of error are used as two statistical criteria to quantify the accuracy and consistency of the model.

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Characterisation of the gas–liquid mass transfer in shaking bioreactors

Cited by 210 publications

References 10 publications

Methods for Intense Aeration, Growth, Storage, and Replication of Bacterial Strains in Microtiter Plates

Methods for Intense Aeration, Growth, Storage, and Replication of Bacterial Strains in Microtiter Plates

Increased bacterial growth efficiency with environmental variability: results from DOC degradation by bacteria in pure culture experiments

Novel dynamic model for aerated shaking bioreactors

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