Interaction between CO2-mass transfer, light availability, and hydrodynamic stress in the growth ofPhaeodactylum tricornutum in a concentric tube airlift photobioreactor

Abstract

The microalga Phaeodactylum tricornutum was grown in a concentric tube airlift photobioreactor. A maximum specific growth rate of 0.023 h−1 was obtained using a superficial gas velocity around 0.055 m/s. Lower or higher gas flow rates limited the culture performance. To establish if the observed limitation was due to CO2 or to the photosynthetically active irradiance, characteristic times for mixing, mass transfer and CO2 consumption, and the photon flux absorbed by the culture were analyzed. The CO2‐gradients in the culture were shown to be responsible for the limitation during the exponential growth phase, and both CO2 and light irradiance were limiting in the linear growth phase. The decrease in specific growth rate relative to the maximum was found to be related to the specific gas‐liquid interfacial area, the length scale of the microeddies and the shear rate. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 317–325, 1998.

The place of diatoms in the biofuels industry

“…Another study examined the passage of two diatom species through pumps and valves and concluded that the extent of cellular damage was related to operational parameters, such as Review Hildebrand, Davis, Smith, Traller & Abbriano the pressure drop and the rotational speed of the pump [153]. Cultivation in our laboratory has revealed that some species are impervious to highly turbulent mixing, whereas others are sensitive to modest agitation, suggesting that species-specific differences need to be taken into account with regard to shear stress; such differences have also been reported in the literature [150,154]. The data suggests that the issue is not with diatoms as a class, but particular diatom species subjected to particular turbulence conditions.…”

“…However, there is some apparent contradiction in the literature concerning this point, in that some studies indicate that diatoms are especially sensitive to shear during cultivation [150,151]. In one report, the authors concluded that micro-eddies on the scale of the cell size were responsible for shear stress [150].…”

Desarrollo preliminar de una metodología de suministro de CO2 a cultivos de Botryococcus Braunii para la producción de biocombustibles

“…En el presente estudio se respaldan dichos resultados, ya que se encontraron aumentos del 18% al 45,9% en la proporción de CO 2 disuelto al usar una piedra difusora sobre un difusor de burbujeo, lo cual puede atribuirse a la influencia opuesta del tamaño de burbuja en el coeficiente de transferencia de masa K L y el área interfacial específica A L [34]. Más aun, se obtuvieron diluciones de CO 2 de hasta 57,5% usando geometrías del fotobiorreactor con diámetro de 8cm y altura de 45cm.…”

Bioreactors: Airlift Reactors

“…ALRs are being increasingly used in processes involving shear-sensitive cells (mammalian, insect, plant cell, and microalgae) (5,17,22,39,(192)(193)(194)(195)(196)(197)(198)(199)(200)(201). This has created the need for considering shear stress as one of the relevant parameters in reactor design.…”