脂肪酶非水相转化失水山梨醇油酸酯

失水山梨醇单油酸酯（Ｓｐａｎ８０）可在非水相中用脂肪酶酶促转化合成．比较不同来源的脂肪酶和不同的非水相系统后发现：来源于假丝酵母的脂肪酶Ｎｏｖｏｚｙｍ４３５在无溶剂系统中有较高合成Ｓｐａｎ８０的能力．同时考察了水分对酯化反应的影响，并对酯化反应的条件如底物摩尔比、用酶量等进行了研究．与化学合成的产品比较，各项指标基本接近，但酶法合成的产品单酯含量较高，达８０％以上

LipaseCatalyzed Synthesis of Sorbitan Esters in NonAqueous Phase

Esterification of sorbitan and oleic acid by lipase in non-aqueous phase under mild reaction conditions was studied initially. Sorbitan was dehydrated previously by controlled chemical process. Lipase-catalyzed esterification was carried out in aqueous phase, organic solvent and solvent-free. The maximum conversion in solvent free system appeared to be higher, up to 90%. A comparison was made for four lipases from different sources, and Novozym(r)435 showed to have the highest catalytic activity. Water content had great influence on enzymatic conversion. Main reaction factors for lipase catalysis were also investigated, including the reaction temperature, reaction time and substrate molar ratio.The prepared oleic sorbitan esters were similar to the commercial products in acid number, hydroxyl number, saponification number and color.However the former have better quality than the latter.The preparative yield for sorbitan monoesters was about 70%, diesters less than 20%.