title: Effect of red cyst cell inoculation and iron(II) supplementation on autotrophic astaxanthin production by Haematococcus pluvialis under outdoor summer conditions.
abstract: The negative effect of heat stress on the autotrophic astaxanthin production by Haematococcus pluvialis has been observed during outdoor culture in summer. Under the summer conditions, the proliferation of vegetative cells was highly halted in the green stage and the inducibility in the biosynthesis of astaxanthin was partly hindered in the red stage. Herein, under outdoor summer conditions in which variations of the diurnal temperature occur, heat-stress-driven inefficient vegetative growth of H. pluvialis was highly improved by inoculating the red cyst cells; thereby, maintaining relatively moderate intracellular carotenoid levels in the green stage. Subsequently, a remarkably enhanced astaxanthin titer was successfully obtained by supplementing 50 μM iron(II) to induce the heat stress-driven Haber-Weiss reaction in the red stage. As a result, the productivity of astaxanthin in the cells cultured under summer temperature conditions (23.4-33.5 °C) using the two methods of red cell (cyst) inoculation and the iron(Fe(2+)) supplementation was increased by 147% up to 5.53 mg/L day compared with that of the cells cultured under spring temperature conditions (17.5-27.3 °C). Our technical solutions will definitely improve the annual natural astaxanthin productivity in H. pluvialis in locations confronted by hot summer weather, particularly in large-scale closed photobioreactor systems.
authors.affiliation: Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, South Korea.
authors.forename: Min-Eui
authors.initials: ME
authors.lastname: Hong
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul 136-713, South Korea.
authors.forename: Yoon Young
authors.initials: YY
authors.lastname: Choi
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul 136-713, South Korea; Green School, Korea University, Seoul 136-713, South Korea. Electronic address: simsj@korea.ac.kr.
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Sim
mesh_terms: D052818:Autotrophic Processes; D018533:Biomass; D002734:Chlorophyll / Q000378:metabolism; D000460:Chlorophyta / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D019587:Dietary Supplements; D004777:Environment; D005296:Ferrous Compounds / Q000494:pharmacology*; D018869:Heat-Shock Response; D006358:Hot Temperature; D008027:Light; D058433:Photobioreactors; D012621:Seasons; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D005296:Ferrous Compounds; D024341:Xanthophylls; D002734:Chlorophyll; C005948:astaxanthine
keywords: Astaxanthin; Haematococcus pluvialis; Iron(Fe(2+)) supplementation method; Photoautotrophic culture; Red cyst cell (aplanospore) inoculation method; Summer outdoor conditions