Growth Enhancement of Dunaliella salina by Microbubble Induced Airlift Loop Bioreactor (ALB)—The Relation between Mass Transfer and Growth Rate

Kezhen Ying, Daniel J. Gilmour, Yuzhen Shi, William B. Zimmerman

Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK.
Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.

DOI: 10.4236/jbnb.2013.42A001                

Abstract

The efficiency of a novel microalgal culture system (an airlift loop bioreactor [ALB] engaged with a fluidic oscillator to produce microbubbles) is compared with both a conventional ALB (producing fine bubbles without the fluidic oscillator) and non-aerated flask culture. The impact of CO₂ mass transfer on Dunaliella salina growth is assessed, through varying the gas (5% CO₂, 95% N₂) dosing flow rate. The results showed that approximately 6 - 8 times higher chlorophyll content was achieved in the aerated ALB cultures than in the non-aerated flasks, and there was a 20% - 40% increase in specific growth rate of D. salina in the novel ALB with microbubbles when compared with the conventional ALB cultures. The increase in chlorophyll content was found to be proportional to the total amount of CO₂ mass transfer. For the same dosing time and flow rate, higher CO₂ mass transfer rate (microbubble dosing) resulted in a greater growth rate.

Keywords

Airlift Bioreactor; Fluidic Oscillator; Dunaliella salina; Specific Growth Rate

Conflicts of Interest

The authors declare no conflicts of interest.

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