利用生物技术生产廿碳五烯酸和廿二碳六烯酸

根据现在的了解，能产生有意义含量的廿碳五烯酸（ＥＰＡ）和廿二碳六烯酸（ＤＨＡ）的微生物有真菌和藻类。在微生物中，多不饱和脂肪酸的合成通常是以单不饱和脂肪酸、油酸为底物。合成途径中，有两个主要的反应，即碳链的增长和去饱和作用。ＥＰＡ和ＤＨＡ的生成通过ω－３代谢途径。微生物脂肪酸构成的质量和数量都受培养基的组分，通气、光照强度、温度和培养时间等环境因素的影响。大多数用于提取鱼油中的ＥＰＡ的方法也可用于微生物脂质中的ＥＰＡ的提取。几种方法被提出来生产高含量的ＥＰＡ和ＤＨＡ。它们一般是基于下列技术的结合：溶剂提取、尿素包合法、分子蒸馏、分馏、液相色谱法和超临界二氧化碳提取。

Producting Eicosapentaenoic Acid and Docosahexenoic Acid by Biotechnology

Fungi and algae have been found to yield significance amount of Eicosapentaenoic acid(EPA) and docosahexenoic acid(DHA).Production are polyunsaturated fatty acids in microorganisms are usually synthesized from the starting monunsaturated fatty acid or oleic acid. There are mainly two reactions involved in the pathways, chain elongation and desaturation. EPA and DHA are produced in the ω-3metabolic directions. Fatty acids compostion of microorganisms, both qualitatively and quantitavely,are influenced by media composition, aeration, light intensity, temperature and culture age. Most of the work on enrichment of EPA have been reported with fish oils only and the same can be applied to microbial lipids also. Several method have been proposed to produce concentrated EPA and DHA. They are generally based upon a combination of techniques. such as solven extraction, urea inclusion. molecular disillation. fractionation distillation, liquid chromatography and supercritical fluid carbon dioxide.