title: Cultivation of shear stress sensitive and tolerant microalgal species in a tubular photobioreactor equipped with a centrifugal pump.
abstract: The tolerance to shear stress ofTetraselmis suecica,Isochrysis galbana,Skeletonema costatum, andChaetoceros muelleriwas determined in shear cylinders. The shear tolerance of the microalgae species strongly depends on the strain.I. galbana,S. costatum, andC. muelleriexposed to shear stress between 1.2 and 5.4 Pa resulted in severe cell damage.T. suecicais not sensitive to stresses up to 80 Pa. The possibility to grow these algae in a tubular photobioreactor (PBR) using a centrifugal pump for recirculation of the algae suspension was studied. The shear stresses imposed on the algae in the circulation tubes and at the pressure side of the pump were 0.57 and 1.82 Pa, respectively. The shear stress tolerantT. suecicawas successfully cultivated in the PBR. Growth ofI. galbana,S. costatum, andC. muelleriin the tubular PBR was not observed, not even at the lowest pumping speed. For the latter shear sensitive strains, the encountered shear stress levels were in the order of magnitude of the determined maximum shear tolerance of the algae. An equation was used to simulate the effect of possible damage of microalgae caused by passages through local high shear zones in centrifugal pumps on the total algae culture in the PBR. This simulation shows that a culture of shear stress sensitive species is bound to collapse after only limited number of passages, confirming the importance of considering shear stress as a process parameter in future design of closed PBRs for microalgal cultivation.
authors: Bioprocess Engineering, AlgaePARC, Wageningen University, P.O. Box 16, 6700 AA Wageningen, The Netherlands.|HZ University of Applied Sciences, P.O. Box 364, 4380 AJ Vlissingen, The Netherlands.
authors: Michiel H A
authors: MHA
authors: Michels
authors: Food Process Engineering, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors: Atze Jan
authors: AJ
authors: van der Goot
authors: Bioprocess Engineering, AlgaePARC, Wageningen University, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
authors: Marian H
authors: MH
authors: Vermuë
authors: Bioprocess Engineering, AlgaePARC, Wageningen University, P.O. Box 16, 6700 AA Wageningen, The Netherlands.|Faculty of Biosciences and Aquaculture, University of Nordland, 8049 Bodø, Norway.
authors: René H
authors: RH
authors: Wijffels
keywords: Microalgae; Recirculation pump; Sensitivity; Shear stress; Tubular photobioreactor