Advances in understanding and modeling the gas–liquid mass transfer in shake flasks

Maier, Ulrike; Losen, Mario; Büchs, Jochen

doi:10.1016/s1369-703x(03)00174-8

Cited by 136 publications

(144 citation statements)

References 27 publications

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“…) from previous reports on gas-liquid mass transfer in shake flask systems (26,44) and further confirmed by in-vessel measurements conducted by a conventional dynamic gassing-out technique as previously described (9).…”

supporting

confidence: 79%

Escherichia coli Strains Engineered for Homofermentative Production of d -Lactic Acid from Glycerol

Mazumdar

Clomburg

González

2010

Appl Environ Microbiol

142

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Given its availability and low price, glycerol has become an ideal feedstock for the production of fuels and chemicals. We recently reported the pathways mediating the metabolism of glycerol in Escherichia coli under anaerobic and microaerobic conditions. In this work, we engineer E. coli for the efficient conversion of glycerol to D-lactic acid (D-lactate), a negligible product of glycerol metabolism in wild-type strains. A homofermentative route for D-lactate production was engineered by overexpressing pathways involved in the conversion of glycerol to this product and blocking those leading to the synthesis of competing by-products. The former included the overexpression of the enzymes involved in the conversion of glycerol to glycolytic intermediates (GlpK-GlpD and GldA-DHAK pathways) and the synthesis of D-lactate from pyruvate (D-lactate dehydrogenase). On the other hand, the synthesis of succinate, acetate, and ethanol was minimized through two strategies: (i) inactivation of pyruvate-formate lyase (⌬pflB) and fumarate reductase (⌬frdA) (strain LA01) and (ii) inactivation of fumarate reductase (⌬frdA), phosphate acetyltransferase (⌬pta), and alcohol/acetaldehyde dehydrogenase (⌬adhE) (strain LA02). A mutation that blocked the aerobic D-lactate dehydrogenase (⌬dld) also was introduced in both LA01 and LA02 to prevent the utilization of D-lactate. The most efficient strain (LA02⌬dld, with GlpK-GlpD overexpressed) produced 32 g/liter of D-lactate from 40 g/liter of glycerol at a yield of 85% of the theoretical maximum and with a chiral purity higher than 99.9%. This strain exhibited maximum volumetric and specific productivities for D-lactate production of 1.5 g/liter/h and 1.25 g/g cell mass/h, respectively. The engineered homolactic route generates 1 to 2 mol of ATP per mol of D-lactate and is redox balanced, thus representing a viable metabolic pathway.

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supporting

confidence: 79%

Escherichia coli Strains Engineered for Homofermentative Production of d -Lactic Acid from Glycerol

Mazumdar

Clomburg

González

2010

Appl Environ Microbiol

142

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“…MOPS minimal medium (41) supplemented with 0.5% (wt/vol) palmitic acid and 0.2% (wt/vol) Brij 58 (Fluka Chemie AG, Buchs, Switzerland) was used. The oxygen transfer rate (k L a) was estimated from previous reports on gas-liquid mass transfer in shake flask systems (37,63) and further confirmed by in-vessel measurements conducted by the conventional dynamic gassing-out technique (14).…”

supporting

confidence: 54%

Engineered Respiro-Fermentative Metabolism for the Production of Biofuels and Biochemicals from Fatty Acid-Rich Feedstocks

Dellomonaco

Rivera²,

Campbell³

et al. 2010

Appl Environ Microbiol

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Although lignocellulosic sugars have been proposed as the primary feedstock for the biological production of renewable fuels and chemicals, the availability of fatty acid (FA)-rich feedstocks and recent progress in the development of oil-accumulating organisms make FAs an attractive alternative. In addition to their abundance, the metabolism of FAs is very efficient and could support product yields significantly higher than those obtained from lignocellulosic sugars. However, FAs are metabolized only under respiratory conditions, a metabolic mode that does not support the synthesis of fermentation products. In the work reported here we engineered several native and heterologous fermentative pathways to function in Escherichia coli under aerobic conditions, thus creating a respiro-fermentative metabolic mode that enables the efficient synthesis of fuels and chemicals from FAs. Representative biofuels (ethanol and butanol) and biochemicals (acetate, acetone, isopropanol, succinate, and propionate) were chosen as target products to illustrate the feasibility of the proposed platform. The yields of ethanol, acetate, and acetone in the engineered strains exceeded those reported in the literature for their production from sugars, and in the cases of ethanol and acetate they also surpassed the maximum theoretical values that can be achieved from lignocellulosic sugars. Butanol was produced at yields and titers that were between 2-and 3-fold higher than those reported for its production from sugars in previously engineered microorganisms. Moreover, our work demonstrates production of propionate, a compound previously thought to be synthesized only by propionibacteria, in E. coli. Finally, the synthesis of isopropanol and succinate was also demonstrated. The work reported here represents the first effort toward engineering microorganisms for the conversion of FAs to the aforementioned products.

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“…These reasons kindled the interest in the use of large scale orbital shaken devices up to thousand liters. [7][8][9] Thus, a large number of researches have been performed on the gas exchange, [10][11][12][13] mixing, [14][15][16][17] and volumetric power consumption 18 of the bioreactors. In some cases, correlations have been proposed in order to quantify the variation of those quantities during scale-up of the culture size.…”

Section: Introductionmentioning

confidence: 99%

Surface wave dynamics in orbital shaken cylindrical containers

et al. 2014

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Be it to aerate a glass of wine before tasting, to accelerate a chemical reaction, or to cultivate cells in suspension, the "swirling" (or orbital shaking) of a container ensures good mixing and gas exchange in an efficient and simple way. Despite being used in a large range of applications this intuitive motion is far from being understood and presents a richness of patterns and behaviors which has not yet been reported. The present research charts the evolution of the waves with the operating parameters identifying a large variety of patterns, ranging from single and multiple crested waves to breaking waves. Free surface and velocity fields measurements are compared to a potential sloshing model, highlighting the existence of various flow regimes. Our research assesses the importance of the modal response of the shaken liquids, laying the foundations for a rigorous mixing optimization of the orbital agitation in its applications. C 2014 AIP Publishing LLC. [http://dx

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Advances in understanding and modeling the gas–liquid mass transfer in shake flasks

Cited by 136 publications

References 27 publications

Escherichia coli Strains Engineered for Homofermentative Production of d -Lactic Acid from Glycerol

Escherichia coli Strains Engineered for Homofermentative Production of d -Lactic Acid from Glycerol

Engineered Respiro-Fermentative Metabolism for the Production of Biofuels and Biochemicals from Fatty Acid-Rich Feedstocks

Surface wave dynamics in orbital shaken cylindrical containers

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