| 题名 | 微藻油脂的提取与藻渣营养特性的研究 |
| 作者 | 梁克红 |
| 学位类别 | 博士 |
| 答辩日期 | 2013-05-01 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 丛威 |
| 关键词 | 微藻 油脂 抗营养因子 水酶法 营养评价 |
| 其他题名 | Study of Extraction of Lipid from Microalgae and Nutritional Characteristics of Algal Residue |
| 学位专业 | 生物化工 |
| 中文摘要 | 微藻富含油脂、蛋白质、多糖、纤维素等多种营养成分，且易于人工繁殖，生长速度快，光合固碳效率高、繁殖周期短。利用微藻生产生物燃料或食用油，充分利用微藻资源，为解决人类面临的能源及食品短缺这些问题提供了一种途径。本文以小球藻作为模式藻，对微藻细胞油脂积累的影响因素，微藻油脂提取及提取油脂后藻渣的营养价值等进行较深入的研究。 首先考察了培养过程中磷对淡水小球藻油脂等代谢产物积累的影响。结果表明，在本实验条件下，淡水小球藻在初始磷浓度是32 μmol/L时，总脂含量达到23.60%，是高磷培养基中小球藻的1.67倍。而小球藻中蛋白质含量受初始磷浓度影响较小，总糖含量随着藻细胞生长呈现先增长后减少的规律。 考察了小球藻中的抗营养因子的存在情况，发现淡水小球藻和海水小球藻中主要有胰蛋白酶抑制剂、凝集素和单宁三种抗营养因子。 考察了不同的溶剂、温度、提取时间等因素对有机溶剂萃取法提取小球藻油脂的影响。以二氯甲烷/甲醇作为溶剂，提取温度为25℃，液固比为10:1，提取12 h，回收率可达94.71%。同时由于有机溶剂提取油脂过程中也溶解了部分抗营养因子，使提取油脂剩余物中的抗营养因子有所减少。藻原料的水分含量和预处理干燥温度也会影响到油脂的回收率，水分含量越多，干燥温度越高，油脂回收率越低。 考察了水酶法提取海洋小球藻的工艺条件。结果表明：加酶量4%，酶解时间12 h时可以获得较高的油脂回收率。采用扫描电镜观察到微藻经过超声及酶解过程，原细胞结构基本破坏，说明超声附加酶解有利于油脂的释放。调节酶水解乳状液的pH值可以有效脱乳，从而提高油脂回收率，通过电位、粒径测定阐明了调节pH值脱乳的机理。由于酶制剂的使用，微藻在利用水酶法提取油脂的同时也使藻细胞中的抗营养因子显著去除，提高了提取油脂剩余物的营养价值。 以一定浓度的乙醇加入到水酶法提取藻油的剩余物中，可以将乳状液中的蛋白质和碳水化合物沉淀下来，并且可以部分除去醇沉沉淀中的抗营养因子，通过营养价值评定和体外消化率的结果表明乙醇处理后的醇沉沉淀是一种优质的新型营养资源。 |
| 英文摘要 | Many microalgae are abundant in lipid, protein, carbohydrate, vitamin and other nutrition, and can be artificially propagated easily with fast growth rate and short reproductive cycle. With the sharp increase of population, the contradiction between lipid demand and the serious shortage of natural resources becomes increasingly intense. As a new source for lipid, microalgae provide a promising measure to address this problem. For the algae residue, a lot of nutrients are still remained. In this study, researches were performed on microalgae cultivation, lipid extraction and nutritional reserves of algae residue by using Chlorella as a model system, and it is intended to provide a theoretical basis for the rational utilization of microalgae. Firstly, batch culture experiments for Chlorella sp. were conducted in order to investigate the effect of different phosphorus supply levels on lipid content and lipid productivity during the growth phase and how these changes affecting the biochemical composition of Chlorella sp. The results showed that the maximum lipid content at the phosphorus concentration of 32 μmol/L was achieved at 23.60%, which was 1.67 times higher than that under high phosphorus medium. The lipid content was decreased when phosphorus was added in the late growth phase. The change of phosphorus concentration had different effects on the carbohydrate and the protein content, in which the protein content was not significantly altered, whereas the carbohydrate content seemed to be dependent of the phosphorus concentration. The presence of anti-nutritional factors in the Chlorella sp. and Chlorella vulgaris was investigated. It was found that trypsin inhibitor, lectin and tannin dominated in the algae. The organic solvent extraction was used to extract lipids from microalgae. Effect of different solvent, temperature and extraction time on lipid recovery was studied. Methylene chloride/methanol was selected as the optimal solvent considering both the lipid recovery and the safety of the solvent. The lipid recovery reached the highest value in 12 h with methylene chloride/methanol as extraction solvent at 25°C. A part of anti-nutritional factors were also dissolved during organic solvent extraction process and decreased in the residue treated with solvent extraction. Higher water content of the algae and the drying temperature could reduce the lipid recovery. The improved lipid extraction process has been investigated for microalge using enzyme-assisted aqueous extraction processing. The results showed the higher lipid recovery was obtained when enzyme dosage was 4% and reaction time was 12 h. In order to get an insight to the enzyme-assisted aqueous extraction process for algal lipid recovery, the algae materials were analyzed by scanning electron microscopy. The effective cracking of cell wall was crucial to the enhancement of the lipid extraction efficiency. The mechanism of the lipid recovery enhanced by adjusting pH value of the emulsion was discussed by detecting Zeta potential and particle size. The anti-nutritional factors were partially removed, thereby improving the nutritional value of the algal residue. The protein and carbohydrates from the emulsion were precipitated by ethanol at different concentrations. Moreover, a part of anti-nutritional factors in the ethanol precipitation were removed. The results of nutritional evaluation and in vitro protein digestibility further verified the ethanol precipitation could be used as a high-quality nutritional resource |
| 语种 | 中文 |
| 公开日期 | 2014-05-23 |
| 页码 | 131 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/8256]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 梁克红. 微藻油脂的提取与藻渣营养特性的研究[D]. 中国科学院研究生院. 2013. |
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