title: Estimation of optimum specific light intensity per cell on a high-cell-density continuous culture of Chlorella zofingiensis not limited by nutrients or CO₂.
abstract: To determine the optimum light intensity per cell required for rapid growth regardless of cell density, continuous cultures of the microalga Chlorella zofingiensis were grown with a sufficient supply of nutrients and CO2 and were subjected to different light intensities in the range of 75-1000 μE m(-2) s(-1). The cell density of culture increased over time for all light conditions except for the early stage of the high light condition of 1000 μE m(-2) s(-1). The light intensity per cell required for the high specific growth rate of 0.5 day(-1) was determined to be 28-45 μE g-ds(-1) s(-1). The specific growth rate was significantly correlated to light intensity (y=0.721×x/(66.98+x), r(2)=0.85, p<0.05). A high specific growth rate was maintained over a range of light intensities (250-1000 μE m(-2) s(-1)). This range of light intensities suggested that effective production of C. zofingiensis can be maintained outdoors under strong light by using the optimum specific light intensity.
authors.affiliation: Department of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan; Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Imaizumi
authors.affiliation: Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia. Electronic address: norio.nagao@upm.edu.my.
authors.forename: Norio
authors.initials: N
authors.lastname: Nagao
authors.affiliation: Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
authors.forename: Fatimah Md
authors.initials: FM
authors.lastname: Yusoff
authors.affiliation: Department of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Taguchi
authors.affiliation: Department of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Toda
mesh_terms: D018533:Biomass; D002245:Carbon Dioxide / Q000494:pharmacology*; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods*; D002708:Chlorella / Q000166:cytology* / Q000254:growth & development / Q000528:radiation effects*; D008027:Light; D058433:Photobioreactors; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide
keywords: Biomass production of microalgae; Chlorella zofingiensis; High-cell-density culture; Nutrient and CO(2) supply; Optimum light condition