生物基塑料单体5-氨基戊酸的生物合成新途径

A new biosynthesis route for production of 5-aminovalanoic acid, a biobased plastic monomer

摘要:

5-氨基戊酸(5-aminovalanoic acid, 5AVA)可作为新型塑料尼龙5和尼龙56的前体，是合成聚酰亚胺的有前途的平台化合物。目前5-氨基戊酸的生物合成法普遍产率较低且合成过程复杂，成本高。为实现5AVA的绿色生物合成，本研究通过组合表达来自日本白腹鲭(Scomber japonicas)的l-赖氨酸α-氧化酶、来自乳酸乳球菌(Lactococcus lactis)的α-酮酸脱羧酶和来自大肠杆菌(Escherichia coli)的醛脱氢酶，在大肠杆菌中建立了一条以l-赖氨酸为原料，以2-酮-6-氨基己酸盐为中间产物生物合成5AVA的途径。在葡萄糖浓度为55 g/L，赖氨酸盐酸盐40 g/L的初始条件下，最终消耗158 g/L的葡萄糖和144 g/L的赖氨酸盐酸盐，补料分批发酵产生了57.52 g/L的5AVA，摩尔得率为0.62 mol/mol。与文献报道的以2-酮-6-氨基己酸盐为中间产物的5AVA生物合成途径相比，本文报道的新途径无需使用乙醇和双氧水，且5AVA产量进一步提高。

关键词:5-氨基戊酸;l-赖氨酸盐酸盐;人工途径;代谢工程

Abstract:

5-aminovalanoic acid (5AVA) can be used as the precursor of new plastics nylon 5 and nylon 56, and is a promising platform compound for the synthesis of polyimides. At present, the biosynthesis of 5-aminovalanoic acid generally is of low yield, complex synthesis process and high cost, which hampers large-scale industrial production. In order to achieve efficient biosynthesis of 5AVA, we developed a new pathway mediated by 2-keto-6- aminohexanoate. By combinatory expression of l-lysine α-oxidase from Scomber japonicus, α-ketoacid decarcarboxylase from Lactococcus lactis and aldehyde dehydrogenase from Escherichia coli, the synthesis of 5AVA from l-lysine in Escherichia coli was achieved. Under the initial conditions of glucose concentration of 55 g/L and lysine hydrochloride of 40 g/L, the final consumption of 158 g/L glucose and 144 g/L lysine hydrochloride, feeding batch fermentation to produce 57.52 g/L of 5AVA, and the molar yield is 0.62 mol/mol. The new 5AVA biosynthetic pathway does not require ethanol and H₂O₂, and achieved a higher production efficiency as compared to the previously reported Bio-Chem hybrid pathway mediated by 2-keto-6-aminohexanoate.

Key words:5-aminovaleric acid;l-lysine;synthetic route;metabolic engineering