title: The effect of iron on growth, lipid accumulation, and gene expression profile of the freshwater microalga Chlorella sorokiniana.
abstract: The effects of iron on the growth, lipid accumulation, and gene expression profiles of the limnetic Chlorella sorokiniana CCTCC M209220 under photoautotrophy were investigated. The addition of iron up to 10(-5) mol l(-l) increased final cell densities by nearly 2-fold at 2.3 × 10(7) cells/ml, growth rate by 2-fold, and the length of the exponential phase by 5 days as compared to unsupplemented controls while 10(-3) mol l(-1) iron was toxic. The lipid content increased from 12 % for unsupplemented cultures to 33 % at 10(-4) mol l(-1) iron while the highest overall lipid yield reached 179 mg l(-1). A genefishing and qPCR comparison between the C. sorokiniana at low and high iron levels indicated increases in the expression of several genes, including carbonic anhydrase involved in microalgal cell growth, as well as acc1 and choline transporter related to lipid synthesis. This study provides insights into changes in gene expression and metabolism that accompany iron supplementation to Chlorella as well as potential metabolic engineering targets for improving growth and lipid synthesis in microalgae.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
authors.forename: Minxi
authors.initials: M
authors.lastname: Wan
authors.forename: Xuejie
authors.initials: X
authors.lastname: Jin
authors.forename: Jinlan
authors.initials: J
authors.lastname: Xia
authors.forename: Julian N
authors.initials: JN
authors.lastname: Rosenberg
authors.forename: Geng
authors.initials: G
authors.lastname: Yu
authors.forename: Zhenyuan
authors.initials: Z
authors.lastname: Nie
authors.forename: George A
authors.initials: GA
authors.lastname: Oyler
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Betenbaugh
mesh_terms: D002708:Chlorella / Q000187:drug effects* / Q000254:growth & development*; D005618:Fresh Water / Q000382:microbiology; D007501:Iron / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects*; D060888:Real-Time Polymerase Chain Reaction; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D007501:Iron