碳酸氢钠、氯化钠和pH对菱形藻EPA累积的影响

摘要

Nitzschia sp. MD1, a diatom characterized by alkaliphilicity, is rich in EPA which belongs to omega-3 polyunsaturated fatty acids. In this study we investigated the effects of NaHCO3 , NaCl and initial pH of medium on the EPA accumulation of Nitzschia sp.. The results showed that NaHCO3 concentration and pH value of the medium has obvious effects on the content of total fatty acids and EPA. Effect trend of NaHCO3, NaCl and pH on EPA accumulation firstly increases and then decreases in the scope of the tests. Among these 3 factors, the optimum condition for EPA accumulation and respective yields are: when the NaHCO3 concentration was at 16.8 g/L, the EPA yield was 8.16 mg/L, and the EPA yield was 12.72 mg/L at a pH of 9.5, 13.24 mg/L at a concentration of 10 g/L NaCl. The results indicated that MD1 showed strong tolerance to high alkaline and saand there were high EPA contents and EPA yields under cultural condition with high alkaline and salt, so it may be a candidate for EPA production.%菱形藻（Nitzschia sp．）MD1藻株是一株具有嗜碱特性，富含二十碳五烯酸（EPA）的硅藻。本研究探讨了培养基中碳酸氢钠（ NaHCO3）、氯化钠（ NaCl）浓度和 pH对菱形藻 MD1 EPA累积的影响。结果显示， NaHCO3浓度和pH对菱形藻MD1总脂肪酸和EPA含量有明显的影响。在试验范围内，NaHCO3、NaCl浓度和pH对EPA产量的影响呈现先增加后降低的趋势。 NaHCO3、NaCl浓度和 pH这3个因素中，最有利于EPA累积的条件和EPA产量分别为：NaHCO3浓度16．8 g/L，EPA产量8．16 mg/L；pH 9．5，EPA产量12．72 mg/L；NaCl浓度10 g/L，EPA产量13．24 mg/L。研究表明，菱形藻MD1具有较强的高碱及高盐耐受性，而且在高碱及高盐培养条件下具有较高的EPA含量和产量，是一株具有生产EPA潜力的微藻。