基于高通量的途径优化适配策略强化己二酸生物合成

A high-throughput pathway optimization strategy for enhancing biosynthesis of adipic acid

摘要:

目的 己二酸是尼龙66和聚对苯二甲酸-己二酸丁二醇酯[poly (butylene adipate-co-terephthalate), PBAT]等塑料的主要单体，具有巨大的市场规模。本研究旨在探索己二酸生物合成途径中各基因的最佳表达水平。方法 通过梯度强度组成型启动子对己二酸合成途径的基因表达水平进行随机组合调控，并利用基于己二酸生物传感器的高通量筛选技术筛选出最优组合菌株。随后，对发酵培养基种类、碳源、金属离子及相应前体物质添加进行了优化。结果 筛选得到的最优组合菌株为大肠杆菌(Escherichia coli) MG1655 Δ8-D47，其己二酸产量为431.32 mg/L。经发酵优化后己二酸摇瓶产量达550.34 mg/L，较对照组Z1菌株提高了134%。结论 本研究表明微生物合成己二酸的代谢途径不平衡是限制其产量提高的主要因素。

Abstract:

Objective Adipic acid is a key monomer for plastics such as nylon 66 and poly (butylene adipate-co-terephthalate) (PBAT), with a vast market potential. This study aims to explore the optimal expression levels of genes in the biosynthetic pathway of adipic acid.Methods We regulated the expression levels of genes in the adipic acid synthesis pathway by randomly combining gradient-strength constitutive promoters. The high-throughput screening based on an adipic acid biosensor was conducted to select the strain with the optimal combination. Subsequently, the fermentation media, carbon sources, metal ions, and precursor substance addition amounts were optimized.Results After screening, the optimal strain Escherichia coli MG1655 Δ8-D47 was obtained, with an adipic acid yield of 431.32 mg/L. After fermentation condition optimization, the yield of adipic acid in a shake flask reached 550.34 mg/L, which represented a 134% increase compared with that of the control strain Z1.Conclusion Metabolic pathway imbalance in microbial synthesis of adipic acid is the main factor limiting the increase in yield.