高产PUFAs微藻的筛

发布时间：2018-11-25 10:54

【摘要】：微藻是多不饱和脂肪酸(polyunsaturated fatty acids,PUFAs)的优质来源,富含人体所需的多种必需脂肪酸。本课题旨在从自然界中筛选出能高产PUFAs的藻种,并通过营养胁迫对藻株进行培养,研究其脂代谢的变化,进一步促进藻株积累PUFAs。同时对筛选出的藻株进行扩大培养,添加于鸡饲料中,研究微藻对鸡蛋品质的改善作用。本课题从来自中国西北部的29份样品中共分离432株微藻,通过尼罗红染色法初步筛选,油脂含量测定与脂肪酸组分分析二次筛选,最终筛选出一株富含PUFAs的藻株S7-M11,其油脂含量占干重的48.32%,PUFAs占总脂肪酸组分的22.19%,经分子生物学鉴定,藻株S7-M11与新月筒柱藻同源性高达98%。对藻株S7-M11进行营养胁迫培养,研究表明,氮充足条件能促进藻细胞生物质积累,并且能使PUFAs在总脂肪酸中的比例提高12.17%,氮缺乏条件会抑制细胞生长,能促进中性脂积累。磷充足条件主要促进藻细胞中单不饱和脂肪酸的积累,而磷缺乏条件在促进中性脂积累的同时,也能使C20:5、C22:5等长链多不饱和脂肪酸的比例得以提升。铁充足条件能促进藻细胞积累油脂,主要提高饱和脂肪酸的百分含量;而铁缺乏条件能使藻细胞PUFAs百分含量升高26.84%,其C18:3,C20:4,C20:5三种重要PUFAs的百分含量均有提升。将藻株S7-M11,小球藻C4和裸藻E8分别添加于鸡饲料进行实验。结果表明,三株藻添加于鸡饲料中不影响蛋鸡生产性能以及鸡蛋品质,但能够将蛋黄颜色提高5-7个色度,并且提高蛋黄中PUFAs占总脂肪酸的比例。三种供试藻株中,S7-M11的效果对蛋黄中PUFAs的提高作用最为明显,该组蛋黄中ω-6 PUFAs与ω-3 PUFAs分别提高了 18.56%与77.57%,并且α-亚麻酸,花生四烯酸和二十二碳六烯酸三种重要的PUFAs均有提高。
[Abstract]:Microalgae is a good source of polyunsaturated fatty acids (polyunsaturated fatty acids,PUFAs), rich in human essential fatty acids. The purpose of this study was to screen algae species with high PUFAs production from nature, and to culture algae strains under nutrient stress, to study the changes of lipid metabolism and to further promote the accumulation of PUFAs. in algae strains. At the same time, the selected algae strain was expanded and added to chicken feed to study the effect of microalgae on egg quality. A total of 432 strains of microalgae were isolated from 29 samples from northwestern China. A strain S7-M11, which was rich in PUFAs, was screened by the method of Nile red staining, the determination of oil content and the analysis of fatty acid composition. Its oil content accounted for 48.32% of the dry weight and the PUFAs accounted for 22.19% of the total fatty acids. The molecular biological identification showed that the homology of the algae strain S7-M11 and the Puccinia caterpillar was as high as 98%. The nutrient stress culture of algae strain S7-M11 showed that nitrogen sufficient condition could promote biomass accumulation of algal cells and increase the proportion of PUFAs in total fatty acids by 12.17%. Nitrogen deficiency could inhibit cell growth. It can promote the accumulation of neutral lipid. Phosphorus sufficient condition mainly promoted the accumulation of monounsaturated fatty acids in algal cells, while phosphorus deficiency promoted the accumulation of neutral lipid and increased the proportion of long chain polyunsaturated fatty acids such as C20: 5 and C22: 5. Iron sufficient condition could promote the accumulation of oil in algal cells and increase the percentage of saturated fatty acids. Iron deficiency could increase the PUFAs content of algal cells by 26.84%, and C18: 3, C20: 4, C20: 5, all had an increase in the content of C18: 3, C20: 4, C20: 5. Chlorella sp. S7-M11, Chlorella vulgaris C4 and E8 were added to chicken feed respectively. The results showed that the growth performance and egg quality of laying hens were not affected by the addition of three algae, but the color of egg yolk was increased by 5-7 colors, and the proportion of PUFAs in egg yolk to total fatty acid was increased. The effect of S7-M11 on the increase of PUFAs in yolk was the most obvious among the three tested algae strains. 蠅 -6 PUFAs and 蠅 -3 PUFAs in egg yolk were increased by 18.56% and 77.57%, respectively, and 伪 -linolenic acid was also found in egg yolk. Arachidonic acid and 22 carbohexaenoic acid are three important PUFAs.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S831.5;Q949.2

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