Oxygen Absorption Rates in Shaken Flasks

Auro, Michael A.; Hodge, Howard M.; Roth, Norman G.

doi:10.1021/ie50572a024

Cited by 34 publications

(12 citation statements)

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“…However, assignment of ''increased product titer'' to ''improved strain or medium'' requires suitable and reproducible experimental conditions (Peter et al, 2004). To date, some typical engineering parameters have been described in shake flasks to ensure defined reaction conditions: The oxygen transfer rate (Anderlei and Büchs, 2001;Anderlei et al, 2004;Auro et al, 1957;Maier and Büchs, 2001;Maier et al, 2004), specific power consumption (Büchs et al, 2000a,b;Kato et al, 1996;Sumino et al, 1972), or mixing time (Gerson and Kole, 2001;Kato et al, 1996) have been studied to provide an engineering basis for scale-up from shake flasks to ensure nonlimiting conditions at all stages of process development.…”

Section: Introductionmentioning

confidence: 99%

Hydromechanical stress in shake flasks: Correlation for the maximum local energy dissipation rate

Peter

Suzuki

Büchs

2006

Biotech & Bioengineering

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Shake flasks are widely used in biotechnological process research. Bioprocesses for which hydromechanical stress may become the rate controlling parameter include those where oils are applied as carbon sources, biotransformation of compounds with low solubility in the aqueous phase, or processes employing animal, plant, or filamentous microorganisms. In this study, the maximum local energy dissipation rate as the measure for hydromechanical stress is characterized in shake flasks by measuring the maximum stable drop size. The theoretical basis for the method is that the maximum stable drop diameter in a coalescence inhibited liquid/liquid dispersion is only a function of the maximum local energy dissipation rate and not of the dispersing apparatus. The maximum local energy dissipation rate is obtained by comparing the drop diameters in shake flasks to those in a stirred tank reactor. At the same volumetric power consumption, the maximum energy dissipation rate in shake flasks is about 10 times lower than in stirred tank reactors explaining the common observation of considerable differences in the morphology of hydromechanically sensitive cells between these two reactor types. At the same volumetric power consumption, the maximum local energy dissipation rate in baffled and in unbaffled shake flasks is very similar. A correlation is presented to quantify the maximum local energy dissipation rate in shake flasks as a function of the operating conditions. Non-negligible drop viscosity may be considered by known literature correlations. Further, from dispersion experiments a critical Reynolds number of about 60,000 is proposed for turbulent flow in unbaffled shake flasks.

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Section: Introductionmentioning

confidence: 99%

Hydromechanical stress in shake flasks: Correlation for the maximum local energy dissipation rate

Peter

Suzuki

Büchs

2006

Biotech & Bioengineering

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“…globigii cultures were grown in CSL with shaking and combined with colony selection (19). Later publications from that period clarify the importance of culture aeration for obtaining high spore yields after 24 h of incubation and provide estimates for the rates of oxygen absorption used in those experiments (2,47). Heat shocks of inocula were used as a purifying selective pressure for the cells that failed to sporulate after 24 h of incubation (19,47).…”

Section: Experimental Designmentioning

confidence: 99%

Effect of the Bacillus atrophaeus subsp. globigii Spo0F H101R Mutation on Strain Fitness

Zhelev

Hunt

et al. 2012

Appl Environ Microbiol

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bSporulation is a critical developmental process in Bacillus spp. that, once initiated, removes the possibility of further growth until germination. Therefore, the threshold conditions triggering sporulation are likely to be subject to evolutionary constraint. Our previous studies revealed two spontaneous hypersporulating mutants of Bacillus atrophaeus subsp. globigii, both containing point mutations in the spo0F gene. One of these strains (Detrick-2; contains the spo0F101 allele with a C:T [His101Arg] substitution) had been deliberately selected in the early 1940s as an anthrax surrogate. To determine whether the experimental conditions used during the selection of the "military" strains could have supported the emergence of hypersporulating variants, the relative fitness of strain Detrick-2 was measured in several experimental settings modeled on experimental conditions employed during its development in the 1940s as a simulant. The congenic strain Detrick-1 contained a wild-type spo0F gene and sporulated like the wild-type strain. The relative fitness of Detrick-1 and Detrick-2 was evaluated in competition experiments using quantitative single nucleotide polymorphism (SNP)-specific real-time PCR assays directed at the C:T substitution. The ancestral strain Detrick-1 had a fitness advantage under all conditions tested except when competing cultures were subjected to frequent heat shocks. The hypersporulating strain gained the maximum fitness advantage when cultures were grown at low oxygen tension and when heat shock was applied soon after the formation of the first heat-resistant spores. This is interpreted as gain of fitness by the hypersporulating strain in fast-changing fluctuating environments as a result of the increased rate of switching to the sporulating phenotype. S porulation in Gram-positive Bacillus species is a critical developmental process that results in the formation from growing vegetative cells of dormant, extraordinarily hardy, persistent endospores (42). The formation of spores is a complex biochemical process (13, 51) linked to starvation that is irreversible once initiated (53). While entry into sporulation occurs with some heterogeneity within otherwise uniform bacterial cultures (10), entry into sporulation across a bacterial population must therefore be optimized to minimize the likelihood that conditions would improve sufficiently to permit additional growth. Failure to time sporulation appropriately would result in missed opportunities for a population of bacteria when nutrient deprivation is transient. In most sporulating bacteria studied to date, sporulation is regulated by a network of sensor kinases that transmit signals via a phosphorelay cascade (21) to Spo0A (15), a transcription factor that is the master regulator of the sporulation regulon. In Bacillus subtilis, the best-studied of sporulating organisms, the Spo0F protein integrates the signals from sensor kinases by accepting a phosphoryl group and relays it to Spo0B (54) and then to Spo0A (23), which directly regulates t...

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“…In addition, the oxygen transfer process in the flask is known to be predominantly influenced by the shaking speed and the oxygen transfer rate usually increases with the increase in shaker speed [26,27]. Therefore, it is considered importantly to keep a suitable level of dissolved oxygen tension or oxygen transfer rate with appropriate rate of shaking in various fermentation processes.…”

Section: Effect Of Rotation Speedmentioning

confidence: 99%

Co‐production of γ ‐glutamylcysteine and glutathione by mutant strain Saccharomyces cerevisiae FC‐3 and its kinetic analysis

Chen

Huang

Cheng

et al. 2009

J. Basic Microbiol.

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Co-production of gamma -glutamylcysteine (gamma -GC) and glutathione (GSH) by a novel mutant strain Saccharomyces cerevisiae FC-3 and its kinetic analysis were investigated. The strain could produce gamma -GC and GSH with high yields (4.22 and 14.3 mg/g-DCW, respectively) in batch submerged cultures. Effects of medium components and cultivation conditions on cell growth and the contents of intracellular gamma -GC and GSH were examined. Results show that 2% (w/v) sucrose and 2.5% (w/v) yeast extract are the best carbon and nitrogen sources, respectively, and supplement of three amino acids (glycine, cysteine and glutamate), each at 0.08% (w/v), in the medium could enhance gamma -GC and GSH production. In addition, optimal operating conditions are at the initial pH value of 7.0, 30 degrees C and 200 rev/min. Moreover, results obtained from kinetic analyses reveal that gamma -GC production is mixed-type growth associated, but GSH production is growth-associated.

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Oxygen Absorption Rates in Shaken Flasks

Cited by 34 publications

References 1 publication

Hydromechanical stress in shake flasks: Correlation for the maximum local energy dissipation rate

Hydromechanical stress in shake flasks: Correlation for the maximum local energy dissipation rate

Effect of the Bacillus atrophaeus subsp. globigii Spo0F H101R Mutation on Strain Fitness

Co‐production of γ ‐glutamylcysteine and glutathione by mutant strain Saccharomyces cerevisiae FC‐3 and its kinetic analysis

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