title: Complementary limiting factors of astaxanthin synthesis during photoautotrophic induction of Haematococcus pluvialis: C/N ratio and light intensity.
abstract: We investigated the effect of carbon/nitrogen (C/N) ratio on astaxanthin synthesis in Haematococcus pluvialis during photoautotrophic induction by continuous input of both CO(2)-air mixture and intense light. When H. pluvialis was induced by constant irradiance induction at 200 micromol photon m(-2) s(-1), there was a positive correlation with astaxanthin content and C/N ratio, which was similar to the case for heterotrophic induction. Lower C/N ratios did not retard Haematococcus encystment, but did increase culture biomass, resulting in a decrease in astaxanthin production because of light limitation. However, induction using variable irradiance showed that reduction of astaxanthin production at low C/N ratios was successfully overcome by simply increasing the light intensity from 200 to 300 micromol photon m(-2) s(-1) to overcome the light limitation. This resulted in a greatly enhanced astaxanthin synthesis in proportion to cell density in cultures with low C/N ratios. Our results indicate that light intensity is more critical than C/N ratio in astaxanthin production by H. pluvialis during photoautotrophic induction.
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: C D
authors.initials: CD
authors.lastname: Kang
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: T H
authors.initials: TH
authors.lastname: Park
authors.forename: S J
authors.initials: SJ
authors.lastname: Sim
mesh_terms: D052818:Autotrophic Processes / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D000460:Chlorophyta / Q000378:metabolism*; D046508:Culture Techniques / Q000379:methods; D007218:Industrial Microbiology; D008029:Lighting; D009584:Nitrogen / Q000378:metabolism*; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D024341:Xanthophylls; D002245:Carbon Dioxide; C005948:astaxanthine; D009584:Nitrogen