title: Salt stress induced lipid accumulation in heterotrophic culture cells of Chlorella protothecoides: Mechanisms based on the multi-level analysis of oxidative response, key enzyme activity and biochemical alteration.
abstract: Salt stress as an effective stress factor that could improve the lipid content and lipid yield of glucose in the heterotrophic culture cells of Chlorella protothecoides was demonstrated in this study. The highest lipid content of 41.2% and lipid yield of 185.8mg/g were obtained when C. protothecoides was stressed under 30g/L NaCl condition at its late logarithmic growth phase. Moreover, the effects of salt and osmotic stress on lipid accumulation were comparatively analyzed, and it was found that the effects of NaCl and KCl stress had no significant differences at the same osmolarity level of 1150mOsm/kg with lipid contents of 41.7 and 40.8% as well as lipid yields of 192.9 and 186.8mg/g, respectively, whereas these results were obviously higher than those obtained under the iso-osmotic glycerol and sorbitol stresses. Furthermore, basing on the multi-level analysis of oxidative response, key enzyme activity and biochemical alteration, the superior performance of salt stress driving lipid over-synthesis was probably ascribed to the more ROS production as a result of additional ion effect besides the osmotic effect, subsequently mediating the alteration from carbohydrate storage to lipid accumulation in signal transduction process of C. protothecoides.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Xiwei
authors.initials: X
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Zejian
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China. Electronic address: guo_mj@ecust.edu.cn.
authors.forename: Meijin
authors.initials: M
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China. Electronic address: juchu@ecust.edu.cn.
authors.forename: Ju
authors.initials: J
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Yingping
authors.initials: Y
authors.lastname: Zhuang
mesh_terms: D002708:Chlorella / Q000187:drug effects / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects*; D008055:Lipids / Q000032:analysis*; D058086:Microalgae / Q000187:drug effects / Q000378:metabolism*; D009997:Osmotic Pressure / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D008055:Lipids; D017382:Reactive Oxygen Species; D012965:Sodium Chloride
keywords: Chlorella protothecoides; Heterotrophic culture; Lipid; Microalgae; ROS; Salt stress