从雨生红球藻藻泥中选择性提取虾青素

Selectively extract astaxanthin from wet biomass of Haematococcus pluvialis

以雨生红球藻湿藻泥为原料,研究了不同有机溶剂对胞内油脂和虾青素选择性提取分离的影响,通过酸解破壁提高虾青素和油脂的提取效率。结果表明,连续乙醇提取可对胞内色素和油脂有效分级提取,先提取出极性组分(叶绿素和极性脂),再提取中性组分(类胡萝卜素和中性脂)。中等极性溶剂或溶剂体系对类胡萝卜素的选择性和提取率较好;乙醇/乙酸乙酯混合溶剂提取类胡萝卜素的总得率(干重)达25.31 mg/g,提取率为69.35%。对雨生红球藻湿细胞进行酸解破壁处理有助于提高虾青素和油脂的提取率。在最优酸解破壁条件(盐酸浓度1 mol/L,温度60℃,时间60 min)下,含水80%的雨生红球藻藻泥的油脂总得率(干重)达418 mg/g,总脂提取率达97%。

Microalgae Haematococcus pluvialis is the richest natural source of astaxanthin and has become the primary source for astaxanthin production so far. However, its thick resistant cell wall probably represents the biggest barrier for target compound extraction. Therefore, high energy-consuming and cost-intensive downstream processes such as cell disruption and drying are required to improve extraction efficiency. In the present study, an approach to selectively extract astaxanthin and lipid using aqueous ethanol from algal biomass of H. pluvialis with moisture content of 80%, following a pre-process of acidichydrolysis cell wall disruption, was proposed. Experiments for parameters optimization and for investigation of mechanism of this approach to improve extraction performance were also carried out. The results showed that polar fractions(mainly chlorophyll and polar lipids) and neutral fractions(mainly carotenoids and triglyceride) were selectively extracted in different extraction cycles, thus fraction extraction was achieved as consequence of the change of ethanol concentration in different extraction cycles. Solvent or solvent mixtures with moderate polarity act out better selectivity and efficiency for carotenoids(mainly astaxanthin), i.e. extraction using ethanol/ethyl acetate mixture gave a total yield of carotenoids reaching 25.31 mg/g of dry weight, a recovery rate of 69.35% and a high content ratio of carotenoids to chlorophyll of 10.6. With assistant of acidic cell-wall disruption, the extraction efficiency of astaxanthin and lipid were significantly improved, in particular, the total yield of lipid reached 418 mg/g dry weight and the recovery rate of lipid reached 97% under the optimal acidic hydrolysis cell-wall disruption conditions of HCl 1 mol/L, temperature of 60 ℃ and time 60 min. The extracted astaxanthin and fatty acid maintained their chemical stability during extraction process. Therefore, this approach for selectivity extraction astaxanthin and triglyceride from wet algal biomass was demonstrated, and could be an alternative with multiple benefits including extraction efficiency improvement and cost reduction, for astaxanthin production from algal biomass of H. pluvialis.