Effect of cultivation mode on microalgal growth and CO2 fixation

The biofixation of carbon dioxide (CO2) by marine microalgae cultivation has been regarded as one of the potential to diminish the greenhouse effect and produce the biomass. To compare and select the high efficiency cultivation mode, the effect of two different cultivation modes on the performances of growth and CO2 biofixation from air for energy marine microalgae Chlorella sp. was determined in this work. In one mode the microalga was cultivated using static (open) method and in the other mode it was cultivated using aerated (closed) method. It was found that, under the experimental conditions, the specific growth rate and CO2 fixation rate of the aerated (closed) cultivation were 0.5121 (d−1) and 1.3784 g CO2/l d, and are 1.78 and 5.39 times that of the static (open) cultivation, respectively. In addition, the effects of pH value and dissolved oxygen (DO) concentration of the culture medium were analyzed and compared in two cultivation modes. The result indicates the aerated (closed) mode can effectively enhance the performance on microalgal growth and CO2 biofixation.

► Effect of static and aerated cultivation modes on the performances of growth and free air CO2 biofixation for energy marine microalgae Chlorella sp. is determined.
► Bubbles and turbulent flow formed by aeration promote gas-liquid diffusion and microalgal photosynthesis.
► Aeration can not significantly decrease pH value but can eliminate the photoinhibited effect.
► Aerated cultivation mode is helpful to effectively enhance the performance on microalgal growth and biofixation CO2.