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

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。

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

The aim of the present study was to investigate the effect of nitrate pulse feeding on the cell growth and cell composition of Desmodesmus sp. F51. Under nitrate pulse-feeding cultivation, the protein content of cells of Desmodesmus sp. F51 decreased 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 in carotenoid, lipid and carbohydrate compositions, it appeared that nitrate pulse feeding could promote β-carotene biosynthesis and enhance the bioconversion of α-carotene to lutein. Lutein accumulation was positively associated with polyunsaturated fatty acid formation. Desmodesmus sp. F51 tended to accumulate carbohydrate as an energy storage product after 3 days of 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 and carbohydrate in Desmodesmus sp. F51.