title: The boosted lipid accumulation in microalga Chlorella vulgaris by a heterotrophy and nutrition-limitation transition cultivation regime.
abstract: A model of heterotrophy and nutrition-limitation transition cultivation for efficient algal biomass and lipid production was proposed in this study, wherein sufficient robust heterotrophic-seed cells submitted into nitrogen-starvation induction for boosted lipid accumulation. The results demonstrated that heterotrophic-seed (HS) achieved specific growth rate of 1.35 day-1and biomass productivity of 1.93 mg/L/d, representing 6.42- and 32.16-fold, 2.01- and 2.75-fold more than that of photoautotrophic-seed (PS) and mixtrophic-seed (MS). Even though subsequent nutrition-limitation cultivation repressed the growth of HS, the overall lipid productivity caused by nitrogen-starvation was not offset by biomass loss. The most favorable lipid productivity (465.61 mg/L/d) of HS was 3.25 and 52.31 times higher than that of MS and PS. The high content of monounsaturated fatty acids (50.13%) over saturated and polyunsaturated fatty acids (totally 47.39%) in HS cells could provide superior oxidation stability and lower viscosity for biofuels generated from algal biomass feedstock. These findings suggested the feasibility of using heterotrophy and nutrition-limitation transition cultivation for enhancing the overall lipid productivity. Further, several critical enzymes (i.e. G3PDH, ME, and ACAD) were highly related to lipid accumulation and showed especially pronounced up-regulation or down-regulation expression in HS, which provide indications for shedding light on the molecular mechanisms of lipid accumulation and a prospective metabolic engineering for lipid production.
authors: School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China.
authors: Tingting
authors: T
authors: Liu
authors: School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China.
authors: Fei
authors: F
authors: Liu
authors: School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China.
authors: Chao
authors: C
authors: Wang
authors: School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China.
authors: Zhenyao
authors: Z
authors: Wang
authors: School of Chemical Engineering, Xiangtan University, Xiangtan, 411105, People's Republic of China. yuqinli2004@126.com.
authors: Yuqin
authors: Y
authors: Li
mesh_terms: D020418:Algal Proteins / Q000378:metabolism*; D056804:Biofuels; D018533:Biomass; D018929:Cell Culture Techniques / Q000379:methods*; D048408:Chlorella vulgaris / Q000378:metabolism / Q000502:physiology*; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D052836:Heterotrophic Processes; D008055:Lipids / Q000096:biosynthesis* / Q000737:chemistry; D009584:Nitrogen / Q000378:metabolism
chemical_list: D020418:Algal Proteins; D056804:Biofuels; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D009584:Nitrogen
keywords: Chlorella vulgaris; Heterotrophy and nutrition-limitation transition cultivation; Lipid accumulation; Regulatory enzymes