脉冲式添加氮源对耐温微藻Desmodesmus sp. F51细胞生长和细胞组成的影响

Effect of Nitrate Pulse-Feeding Cultivation on Cell Growth and Cell Composition of Thermo-Tolerant Desmodesmus sp. F51

考察脉冲式添加氮源培养对耐温微藻Desmodesmus sp.F51细胞生长和细胞组成的影响。结果表明,在脉冲式添加氮源培养过程中,藻株F51的蛋白质含量由(560±16)mg/g降低至(456±17)mg/g,而碳水化合物和油脂含量则分别由(209±13)mg/g和(98±3)mg/g提高至(310±12)mg/g和(120±4)mg/g。另外,对色素和油脂的具体组成变化进行分析,发现脉冲式添加氮源培养可增强β-胡萝卜素的生物合成,以及促进α-胡萝卜素生物转化为叶黄素,同时还可发现叶黄素积累与多不饱和脂肪酸含量变化呈正相关性。而在碳水化合物的具体组成分析中,发现碳水化合物为藻株F51主要的储能物质,当脉冲式添加氮源培养时间为3 d时,其葡萄糖占总碳水化合物的质量分数可明显提高至(75.7±1.4)%。采用脉冲式添加氮源培养策略可明显同时促进藻株F51叶黄素和碳水化合物的生产。

The aim of the present study was to investigate the effect of nitrate pulse feeding on the cell growth and cellcomposition of Desmodesmus sp.F51.Under nitrate pulse-feeding cultivation,the protein content of cells of Desmodesmussp.F51decreased from(560±16)mg/g to(456±17)mg/g,while the contents of carbohydrate and lipid increased from(209±13)mg/g to(310±12)mg/g and(98±3)mg/g to(120±4)mg/g,respectively.By investigating the changes incarotenoid,lipid and carbohydrate compositions,it appeared that nitrate pulse feeding could promoteβ-carotene biosynthesisand enhance the bioconversion ofα-carotene to lutein.Lutein accumulation was positively associated with polyunsaturatedfatty acid formation.Desmodesmus sp.F51tended to accumulate carbohydrate as an energy storage product after3daysof cultivation under nitrate pulse-feeding conditions,and the major accumulated monosaccharide was glucose(75.7±1.4)%.Therefore,the nitrate-pulse feeding strategy is a highly promising approach to simultaneously produce lutein andcarbohydrate in Desmodesmus sp.F51.