无溶剂体系中N~α-乙酰谷氨酰甘油的酶法合成研究

Enzymatic synthesis of N~α-acetyl-L-glutamyl glycerol in solvent free system

研究了无溶剂体系中酶催化N-乙酰谷氨酸、甘油合成Nα-乙酰谷氨酸甘油酯的可行性。不同来源的商业酶制剂对比研究发现,固定化的Novozyme435、LipozymeRMIM、TLIM的活力明显高于游离的木瓜蛋白酶、胃蛋白酶及酰化酶及LAP15.最优酶制剂为Novo435,24h酯化率随温度提高、甘油/N-乙酰谷氨酸摩尔比增加而明显增大,酶添加量0.5%～5%范围内酯化率没有显著变化。产物中主要为1(3)-Nα-乙酰基谷氨酰-1-酰基单甘油酯,约占60%～70%,2位异构体约占20%～30%,此外有微量Nα-乙酰基谷氨酰-5-酰基单甘油酯。结果表明,生物法合成Nα-乙酰谷氨酸甘油酯是可行的。

Enzymatic synthesis of N^α-acetyI-L-glutamyl glycerol with N^α-acetyI-L-glutamic acid and glycerol as substrate was investigated in this paper. Screening experiments of commercial catalysts suggested that immobilized catalyst, such as Novozyme 435, Lipozyme RMIM, TLIM is more active than free enzyme （Papyard, pepsin, Acylase and LAP-15）. Novozyme 435 was the optimal catalyst for esterification reaction, the conversion of 24 h increased with temperature, glycerol/N^α-acetyI-L-glutamic acid ratio, however enzyme load did not have significant effects. Among products, l（3）-O-（N^α-acetyI-L-glutam-l-yl） glycerol is dominant, made up 60%-80% of total yields, and 2-O-（N^α-acetyI-L-glutam-l-yl） glycerol consist of 20%-30% due to isomerization. In addition, there are minor of 1-O-（N^α-acetyI-L-glutam-l-yi） glycerol.