Reduction of CO2 by a high-density culture of Chlorella sp. in a semicontinuous photobioreactor.
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 gL(-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 gh(-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.
Chiu
Sheng-Yi
SY
Department of Biological Science and Technology, National Chiao Tung University, No. 75 Po-Ai Street, Hsinchu 30068, Taiwan.
Kao
Chien-Ya
CY
Chen
Chiun-Hsun
CH
Kuan
Tang-Ching
TC
Ong
Seow-Chin
SC
Lin
Chih-Sheng
CS
D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D002138:Calibration; D002245:Carbon Dioxide / Q000378:metabolism* / Q000494:pharmacology; D002708:Chlorella / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D008055:Lipids / Q000096:biosynthesis; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects
D008055:Lipids; D002245:Carbon Dioxide