脂肪酶粉催化酯化合成三羟甲基丙烷酯

以辛酸、癸酸和三羟甲基丙烷作为反应底物，利用 Candida sp. 99-125脂肪酶粉催化反应，研究了反应条件对酶法合成三羟甲基丙烷三辛癸酸酯的影响，并在实验中找到一种可以提高酶粉稳定性的添加剂β-环糊精。结果表明，加入0.01 mol三羟甲基丙烷(TMP) (1.34g)，n_{三羟甲基丙烷}/n _{(癸酸+辛酸)}=1∶4，其中n_癸酸∶n_辛酸=1∶1，添加水的质量分数为0.05%(以底物总质量为基准)、脂肪酶粉的质量分数为12%(以底物总质量为基准)、β-环糊精的质量为酶粉质量的1.5倍，40 ℃下在恒温摇床中，振荡反应130 h，转速130r/min。在此条件下，反应产物三羟甲基丙烷三辛癸酸酯(三羟基酯)的质量分数可达到80% 左右，酸与酯分离后收率可达96%；连续使用6批添加了 β-环糊精的脂肪酶粉，三羟基酯的质量分数可保持在60%以上，与固定化酶的使用寿命相当。

Synthesis of trimethylolpropane esters by powdered lipase-catalyzed esterification

The enzymatic production of trimethylolpropane(TMP) esters from the reaction of octanoic acid and decanoic acid with TMP in the presence of powdered lipase Candida sp.99-125 in a solvent-free system has been studied.The effects of varying the experimental conditions were studied in order to optimize the process.A maximum mass fraction of 80% of triesters was obtained after 130h under the following optimized conditions: 0.01 mol TMP,nTMP/n(octanoic acid+decanoic acid)=1∶4,noctanoic acid/ndecanoic acid=1∶1,0.05%(mass fraction) of added water(based on the weight of total substrate),12%(mass fraction) of powdered lipase(based on the weight of total substrate),with added β-cyclodextrin(1.5 times the mass of powdered lipase),at 40 ℃.After separating the products,the yield of triester reached 96%.Moreover,the powdered lipase with added β-cyclodextrin could be used continuously in six batches with the final mass fraction of triester remaining over 60%.