title: Sequential accumulation of starch and lipid induced by sulfur deficiency in Chlorella and Parachlorella species.
abstract: The influence of sulfur deficiency on biomass production was analyzed in the four Chlorellaceae species, Chlorella vulgaris, Chlorella sorokiniana, Chlorella lobophora, and Parachlorella kessleri. Culturing under sulfur-deficient conditions promoted transient accumulation of starch followed by a steady increase in lipid storage. Transmission electron microscopy indicated an increase and decrease in starch granules and subsequent enlargement of lipid droplets under sulfur-deficient conditions. Chlorellaceae spp. accumulated 1.5-2.7-fold higher amounts of starch and 1.5-2.4-fold higher amounts of lipid under sulfur-deficient conditions than under sulfur-sufficient conditions. More than 75% of the fatty acids that accumulated in Chlorellaceae spp. under the sulfur-sufficient condition were unsaturated and culturing under sulfur-deficient conditions increased the saturated fatty acid content from 24.3% to 59.7% only in P. kessleri. These results indicate that the sequential accumulation of starch and lipid is a response to the sulfur depletion that commonly occurs in Chlorellaceae spp.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Mizuno
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sato
authors.forename: Koichi
authors.initials: K
authors.lastname: Watanabe
authors.forename: Aiko
authors.initials: A
authors.lastname: Hirata
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takeshita
authors.forename: Shuhei
authors.initials: S
authors.lastname: Ota
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sato
authors.forename: Vilém
authors.initials: V
authors.lastname: Zachleder
authors.forename: Mikio
authors.initials: M
authors.lastname: Tsuzuki
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kawano
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D002708:Chlorella / Q000145:classification* / Q000378:metabolism*; D050356:Lipid Metabolism / Q000502:physiology*; D013045:Species Specificity; D013213:Starch / Q000302:isolation & purification / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*
chemical_list: D013455:Sulfur; D013213:Starch