title: Overcoming shear stress of microalgae cultures in sparged photobioreactors.
abstract: In the present work we identified and quantified the effect of hydrodynamic stress on two different microalgae strains, Dunaliella tertiolecta and D. salina, cultivated in bench-scale bubble columns. The cell death rate constant increased with increasing gas-entrance velocity at the sparger. Dunaliella salina was slightly more sensitive than D. tertiolecta. The critical gas-entrance velocities were approximately 50 and 30 m s(-1) for D. tertiolecta and D. salina, respectively. The effects of gas-flow rate, culture height, and nozzle diameter on the death rate constant were also studied. From these results it was concluded that bubble rising and bubble bursting are not responsible for cell death. Regarding nozzle diameter, small nozzles were more detrimental to cells. The bubble formation at the sparger was found to be the main event leading to cell death.
authors.affiliation: Food and Bioprocess Engineering Group, Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands. Maria.Barbosa@wur.nl
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Barbosa
authors.lastname: Hadiyanto
authors.forename: René H
authors.initials: RH
authors.lastname: Wijffels
mesh_terms: D000399:Air Pressure; D017209:Apoptosis / Q000502:physiology; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division / Q000502:physiology / Q000528:radiation effects; D002470:Cell Survival / Q000502:physiology; D000460:Chlorophyta / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects; D005740:Gases; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D018462:Photobiology / Q000379:methods; D010812:Physical Stimulation / Q000379:methods; D033081:Shear Strength; D013045:Species Specificity
chemical_list: D005740:Gases