四株高产油脂及类胡萝卜素微藻的研究

	四株高产油脂及类胡萝卜素微藻的研究; Study of four microalgae with high production of lipids and carotenoids
	巩宇豪
导师	黄俊潮
摘要	Photosynthetic algae are the primary carbon productivity in ocean and inland water bodies. They are vital important to the earth’s ecosystem by providing the primary nutrients and food sources. Algae have potential to solve the shortage of natural resource due to their fast growth rates and abundant metabolites. Moreover, algae can effectively modulate their growth and metabolism according to light and nutrient conditions. Therefore, understanding the underlying mechanism can help to reroute metabolism toward important chemicals for energy, foods, and pharmaceuticals via metabolic engineering. Yunnan is the center of species diversity in China, in which a large number of microalgae may be preserved. This study focuses on the exploitation of industriously important microalgae located in Honghe Hani Terraces where ducks are able to lay eggs with red yolks that contain much higher amounts of lipids and carotenoids than yellow-yolk eggs. More than 200 algal strains were isolated from two locations of the Hani Terraces. After serious culture and assessment of their growth capacity in photoautotrophic, mixotrophic and heterotrophic modes, four strains were achieved with potential for high-yield production of carotenoids and lipids. Selenastraceae sp. B10 could accumulate 7.49 mg g-1 lutein and 63.15 % (% of DCW) lipids. The fatty acid compositions showed that MUFA and SFA of strain B10 accounted for 85 % of total fatty acids. The unique fatty acid composition makes Selenastraceae sp. B10 a superior feedstock for biofuel production. Scenedesmus sp. DHS is the only one among the four strains that synthesizes astaxanthin. In addition, Scenedesmus sp. DHS exhibited the best one in utilizing glucose for biomass accumulation. Pectinodesmus sp. F13 could serve as a cell factory for lutein production due to its up to 5.60 mg d-1L-1 of lutein productivity. Chlorella sp. Mg could yield α-linolenic acid at 37.19 % of total fatty acids under photoautotrophic mode, and a lutein content of 6.80 mg g-1 in mixotrophy. Interestingly, mixotrophic Chlorella sp. Mg gained much less biomass than heterotrophic one, which was opposite to other microalgae. Chlorella sp. Mg was selected to investigate the regulation of algal growth and nutrient metabolism. Based on the data of transcriptome, pigment profiles, photosynthetic and growth parameters, we proposed that exogenous glucose did not slow down the photosynthesis of Chlorella sp. Mg, leading to the enhancement of photorespiration and ROS generation, and hence resulting in biomass loss. That Chlorella sp. Mg produced high amounts of α-linolenic acid only under light condition was correlated to the light-dependent expression of FAD7/8 fatty acid dehydrogenase, a key enzyme involved in converting linoleic acid to α-linolenic acid. In addition, Chlorella sp. Mg was found to highly resist to norflurazon, which was shown to be associated with the algal specific phytoene desaturase (PDS) that was able to convert phytoene to ξ-car
	2020-05
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74125
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	巩宇豪. 四株高产油脂及类胡萝卜素微藻的研究, Study of four microalgae with high production of lipids and carotenoids[D],2020.

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