大肠杆菌中酪醇高效生物合成体系的构建与优化

Construction and Optimization of an Efficient Tyrosol Biosynthesis System in Escherichia coli

摘要:

【目的】在大肠杆菌中构建高效的生物合成系统，实现酪胺及其关键衍生物酪醇的高效生产。【方法】通过分析蛋白质表达、酶学性质和全细胞催化结果，确定源自粪肠球菌的酪氨酸脱羧酶（TDC）作为合成酪胺的关键酶，并以酪胺氧化酶（TYO）来构建合成酪醇的TDC-TYO合成途径。同时，构建LAAD-PDC酪醇合成途径，建立了双酶共表达系统，对比双酶串联顺序、生产途径和关键酶来源对酪醇产量的影响。通过全细胞催化得到携带质粒pET28a-EfTDC-TYO的高产酪醇的重组菌株B1，并对反应条件进行优化。【结果】在最佳反应参数下，24 h内重组菌株B1酪醇产量达3.96 g/L，底物转化率为51.9%。【结论】为生物法合成酪醇及其衍生物提供了参考。

Abstract:

[Objective] An efficient biosynthetic system was constructed in Escherichia coli to achieve high-yield production of tyramine and its key derivative tyrosol.[Method] Through the analysis of protein expression, enzymatic properties, and whole-cell catalysis results, tyrosine decarboxylase (TDC) derived from Enterococcus faecalis was selected as the key enzyme for tyramine synthesis. Subsequently, tyramine oxidase (TYO) was introduced to construct the TDC-TYO pathway for tyrosol production. Meanwhile, the LAAD-PDC pathway for tyrosol synthesis was established. A dual-enzyme co-expression system was established, and the effects of tandem enzyme order, production pathways, and key enzyme sources on tyrosol yield were analyzed. The recombinant strain B1, carrying the plasmid pET28a-EfTDC-TYO, was obtained through whole-cell catalysis, and the reaction conditions were optimized.[Result] Under optimal reaction parameters, the recombinant strain B1 achieved a tyrosol yield of 3.96 g/L within 24 h, with a substrate conversion rate of 51.9%.[Conclusion] This study provides valuable insights for the biosynthesis of tyrosol and its derivatives.