Reduction of CO2 by a high-density culture of Chlorella sp. in a semicontinuous photobioreactor

Sheng Yi Chiu, Chien Ya Kao, Chiun-Hsun Chen, Tang Ching Kuan, Seow Chin Ong, Chih-Sheng Lin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

438 Scopus citations


The microalga incorporated photobioreactor is a highly efficient biological system for converting CO2 into biomass. Using microalgal photobioreactor as CO2 mitigation system is a practical approach for elimination of waste gas from the CO2 emission. In this study, the marine microalga Chlorella sp. was cultured in a photobioreactor to assess biomass, lipid productivity and CO2 reduction. We also determined the effects of cell density and CO2 concentration on the growth of Chlorella sp. During an 8-day interval cultures in the semicontinuous cultivation, the specific growth rate and biomass of Chlorella sp. cultures in the conditions aerated 2-15% CO2 were 0.58-0.66 d-1 and 0.76-0.87 g L-1, respectively. At CO2 concentrations of 2%, 5%, 10% and 15%, the rate of CO2 reduction was 0.261, 0.316, 0.466 and 0.573 g h-1, and efficiency of CO2 removal was 58%, 27%, 20% and 16%, respectively. The efficiency of CO2 removal was similar in the single photobioreactor and in the six-parallel photobioreactor. However, CO2 reduction, production of biomass, and production of lipid were six times greater in the six-parallel photobioreactor than those in the single photobioreactor. In conclusion, inhibition of microalgal growth cultured in the system with high CO2 (10-15%) aeration could be overcome via a high-density culture of microalgal inoculum that was adapted to 2% CO2. Moreover, biological reduction of CO2 in the established system could be parallely increased using the photobioreactor consisting of multiple units.

Original languageEnglish
Pages (from-to)3389-3396
Number of pages8
JournalBioresource Technology
Issue number9
StatePublished - 1 Jun 2008


  • Biomass
  • Carbon dioxide
  • Chlorella sp.
  • Microalga
  • Photobioreactor

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