Effects of mechanical and hydrodynamic stress in agitated, sparged cultures of Porphyridium cruentum

Camacho, F. Garcı́a; Gómez, Antonio Contreras; Sobczuk, Tania Mazzuca; Grima, E. Molina

doi:10.1016/s0032-9592(00)00138-2

Cited by 82 publications

(49 citation statements)

References 19 publications

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“…A high turbulence magnitude produces large hydrodynamic stresses on microalgal cells, and these stresses damage the cells' mechanical structure (cell wall) [17,37]. Therefore, the cell wall of a spherical microalgal cell (Chlorella) was modeled as an elastic structure filled with cytoplasm [33,38].…”

Section: Microalgal Cell Wall Structurementioning

confidence: 99%

“…The maximum von Mises stress at location A showed that the microalgal cell exhibited high resistance to cell wall deformation, whereas the minimum von Mises stress at the remaining locations (B, C, and D) indicated low resistance to wall deformation. These results suggest that the leading edge of microalgal cells is considerably fragile, especially when the microalgal cells are near the paddle wheel (location A), which may affect algal productivity [17,37]. Contour plots of the cell wall deformation (nm) of five microalgal cells were created at various locations in the raceway pond to visualize microalgal cells damage effectively ( Figure 5).…”

Section: Effects Of Microalgal Cell Locationsmentioning

confidence: 99%

“…These results suggest that turbulent mixing is effective in raceway ponds with small ARs; it increases sunlight distribution and nutrient diffusion to the microalgal cell surface. However, narrow raceway ponds (small ARs) result in large cell wall deformations, which indicate the possibility of substantial damage on microalgal cells, and thus reduce cell productivity [15,17,19,20]. …”

Section: Effects Of Aspect Ratiomentioning

confidence: 99%

“…Thomas and Gibson [16] used fluid mechanical properties (dissipation rate, microeddy length, and shear stress) to observe the effects of turbulence on different microalgal species. The paddle wheel must generate microeddies with a length larger than the cell size to avoid damaging the microalgal cell [16][17][18]. Increasing the agitation rates also increases the hydrodynamic stresses that affects the algal cell damage [17,19,20].…”

Section: Introductionmentioning

confidence: 99%

“…The paddle wheel must generate microeddies with a length larger than the cell size to avoid damaging the microalgal cell [16][17][18]. Increasing the agitation rates also increases the hydrodynamic stresses that affects the algal cell damage [17,19,20]. Hadiyanto et al [21] used a commercial computational fluid dynamics (CFD) code to model hydrodynamic mixing in a raceway pond.…”

Section: Introductionmentioning

confidence: 99%

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Determination of the Structural Characteristics of Microalgal Cells Walls under the Influence of Turbulent Mixing Energy in Open Raceway Ponds

2018

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Turbulent flow mixing is essential in optimizing microalgal cultivation in raceway ponds. Microalgal cells are however highly sensitive to hydrodynamic stresses produced by turbulent mixing because of their small size. The mechanical properties (wall deformation and von Misses stress) of the microalgal cell wall structure under the influence of turbulent mixing are yet to be explored. High turbulence magnitudes damage microalgal cell walls by adversely affecting their mechanical properties which consequently destroy the microalgal cells and reduce the biofuel production. Therefore, such a study is required to improve the biofuel productivity of microalgal cells before their cell wall damage in raceway pond. This study developed a novel fluid-structure interaction (FSI)-based numerical model to investigate the effects of turbulent mixing on the cell wall damage of microalgal cells in raceway ponds. The study investigated microalgal cell wall damage at four different locations in a raceway pond in consideration of the effects of pond's hydrodynamic and geometric properties. An experiment was conducted with a laboratory-scale raceway pond to compare and validate the numerical results by using time-dependent water velocities. Microalgal cell wall shear stress, cell wall deformation, and von Misses stress in the raceway pond were investigated by considering the effects of aspect ratios, water depths, and paddle wheel rotational speeds. Results showed that the proposed numerical model can be used as a prerequisite method for the selection of appropriate turbulent mixing. Microalgal cell wall damage is high in shallow and narrow raceway ponds with high paddle rotational speeds.

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Section: Microalgal Cell Wall Structurementioning

confidence: 99%

Section: Effects Of Microalgal Cell Locationsmentioning

confidence: 99%

Section: Effects Of Aspect Ratiomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of the Structural Characteristics of Microalgal Cells Walls under the Influence of Turbulent Mixing Energy in Open Raceway Ponds

2018

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Shear Sensitivity

Chisti

2009

Encyclopedia of Industrial Biotechnology

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Susceptibility to hydrodynamic and mechanical shear forces affects performance of cultured cells of animals, plants, microalgae, and cyanobacteria. In addition, hydromechanical forces affect or otherwise damage some commercially relevant mycelial fungi, filamentous bacteria, microbial flocs, and biofilms. In specific cases, intense shear fields may also damage the larger bioactive molecules such as enzymes. This article details the shear sensitivity of the major types of biocatalysts and the approaches available for mitigating the damaging effects. Methods for estimating shear rate and shear stress are discussed for various configurations of bioreactors operated in process‐relevant conditions.

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