Ma Gaojian, Dai Lingmei, Liu Dehua, Du Wei
Department of Chemical Engineering, Tsinghua University, Beijing, China.
Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing, China.
Front Bioeng Biotechnol. 2019 Dec 20;7:393. doi: 10.3389/fbioe.2019.00393. eCollection 2019.
DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) contained in glycerides have been reported to be more advantageous for their intake than their counterpart in the form of free fatty acid or fatty acid esters. This work attempts to achieve the flexible concentration of DHA and EPA in glycerides as well as biodiesel production via a two-step process catalyzed by lipases. In the first step, several commercial lipases were investigated and Novozym ET2.0 demonstrated the highest potential in selective concentration of DHA and EPA. Over 85% of EPA and other fatty acids were converted to its corresponding FAEEs (fatty acid ethyl esters), while over 80% of DHA remained in glycerides under the optimized conditions. After the first step ethanolysis, the oil phase was subject to molecular distillation and a 97.5% biodiesel (FAEE) content could be obtained. Further flexible enrichment of DHA and EPA in glycerides was realized by immobilized lipase Novozym 435-mediated transesterification of glycerides (remaining in the heavy phase after molecular distillation) with DHA- or EPA-rich EE, and glycerides with 67.1% DHA and 13.1% EPA, or glycerides with 41.1% EPA and 38.0% DHA could be obtained flexibly. This work demonstrated an effective approach for DHA and EPA enrichment combined with biodiesel production through enzymatic catalysis.
据报道，甘油酯中所含的二十二碳六烯酸（DHA）和二十碳五烯酸（EPA）比游离脂肪酸或脂肪酸酯形式的同类物质在摄入方面更具优势。这项工作试图通过脂肪酶催化的两步法实现甘油酯中DHA和EPA的灵活浓缩以及生物柴油的生产。在第一步中，研究了几种商业脂肪酶，诺维信ET2.0在DHA和EPA的选择性浓缩方面显示出最高潜力。在优化条件下，超过85%的EPA和其他脂肪酸转化为其相应的脂肪酸乙酯（FAEEs），而超过80%的DHA保留在甘油酯中。第一步乙醇解后，油相进行分子蒸馏，可获得97.5%的生物柴油（FAEE）含量。通过固定化脂肪酶诺维信435介导甘油酯（分子蒸馏后留在重相中的）与富含DHA或EPA的乙酯进行酯交换反应，实现了甘油酯中DHA和EPA的进一步灵活富集，可灵活获得含67.1%DHA和13.1%EPA的甘油酯，或含41.1%EPA和38.0%DHA的甘油酯。这项工作展示了一种通过酶催化实现DHA和EPA富集并结合生物柴油生产的有效方法。
