Characterisation of Hydrodynamics in an Airlift Bio-Reactor Using a Real Fermentation Broth

Dolgoš, Ondrej; Klein, Jaroslav; Blažej, M.; Markoš, Jozef

doi:10.1002/1522-2640(200106)73:6<750::aid-cite7503333>3.0.co;2-k

Cited by 2 publications

(2 citation statements)

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“…The technique was already successfully tested to measure the particle and liquid velocities in an internal-loop airlift bioreactor with both two-and three-phase model systems (water-air and water -air -alginate beads) (Klein et al, 2003a) as well as during gluconic acid production (Dolgos et al, 2001).…”

Section: Hydrodynamic Measurementsmentioning

confidence: 99%

Relationships between hydrodynamics and rheology of flocculating yeast suspensions in a high‐cell‐density airlift bioreactor

Klein

Maia

Vicente

et al. 2005

Biotech & Bioengineering

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In this article a hydrodynamic and rheological analysis of a continuous airlift bioreactor with high-cell-density system is presented. A highly flocculating recombinant strain of Sacharomyces cerevisiae containing genes for lactose transport (lactose permease) and hydrolysis (beta-galactosidase) was exploited to ferment lactose from cheese whey to ethanol. The magnetic particle-tracer method was used to assess the effect of operational conditions (air-flow rate, biomass concentration) on hydrodynamic behavior of an airlift bioreactor during the fermentation process. Measurements of liquid circulation velocity showed the existence of a critical value of biomass concentration at which a dramatic deceleration of net liquid flow appeared with increasing biomass quantity. Rheological analysis revealed exponential increase of viscosity of the yeast floc suspension at the same biomass concentration of about 73 g/dm3 corresponding to 42.8% v/v of solid fraction. These facts have a particular importance for the successful processing of a high-cell-density airlift bioreactor as only a circulated flow regime will be favorable to keep the solid particles in suspension state and evenly distributed throughout the bioreactor.

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Section: Hydrodynamic Measurementsmentioning

confidence: 99%

Relationships between hydrodynamics and rheology of flocculating yeast suspensions in a high‐cell‐density airlift bioreactor

Klein

Maia

Vicente

et al. 2005

Biotech & Bioengineering

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“…However, in such a configuration, this device is not suitable for use in bioprocesses owing to bioreactor sterility and biomass adhesion problems. The technique using a magnetic particle and inductive coils placed outside the reactor at the outer wall of the column was described by Klein et al 9 The technique was then successfully tested to measure the particle and liquid velocities in both main sections of an internal‐loop airlift bioreactor during gluconic acid production10 and continuous alcoholic fermentation of cheese whey 11…”

Section: Introductionmentioning

confidence: 99%

Motion of a magnetic flow follower in two‐phase flow — application to the study of airlift reactor hydrodynamics

Klein

Godó

Teixeira

2006

J of Chemical Tech & Biotech

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A low-cost and simple magnetic particle tracer method was adapted to characterize the hydrodynamic behavior of an internal-and an external-loop airlift reactor (ALR). The residence time distribution of three magnetic particles differing in diameter (5.5, 11.0 and 21.2 mm) and with a density very close to that of water was measured in individual reactor sections. The measured data were analyzed and used to determine the velocity of the liquid phase. Validation of the experimental results for liquid velocity was done by means of the data obtained by an independent reference method. Furthermore, analysis of the differences found in the settling velocity of the particle in single-liquid and gas-liquid phases was carried out, using a simplified 3D momentum transfer model. The model considering particle-bubble interaction forces resulting from changes in the liquid velocity field due to bubble motion was able to predict satisfactorily the increase in the particle settling velocity in the homogeneous bubbly regime. The effective drag coefficient in two-phase flow was found to be directly dependent on particle Reynolds number to the power of −2 but independent of gas flow-rate for all particle diameters studied. Based on the experimental and theoretical investigations, the valid exact formulation of the effective buoyancy force necessary for the calculation of the correct particle settling velocity in two-phase flow was done. In addition, recommendations concerning the use of flow-following particles in internal-loop ALRs for liquid velocity measurements are presented.  2006 Society of Chemical IndustryKeywords: multiphase flow; airlift reactors; hydrodynamics; momentum transfer; solid mechanics, flow followerRe p Reynolds number of particle

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Characterisation of Hydrodynamics in an Airlift Bio-Reactor Using a Real Fermentation Broth

Cited by 2 publications

References 0 publications

Relationships between hydrodynamics and rheology of flocculating yeast suspensions in a high‐cell‐density airlift bioreactor

Relationships between hydrodynamics and rheology of flocculating yeast suspensions in a high‐cell‐density airlift bioreactor

Motion of a magnetic flow follower in two‐phase flow — application to the study of airlift reactor hydrodynamics

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