Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Institute of Food Science Technology Nutrition and Health (Cangzhou), Chinese Academy of Agricultural Sciences, Cangzhou 061001, China.
J Agric Food Chem. 2024 Jul 3;72(26):14809-14820. doi: 10.1021/acs.jafc.4c03128. Epub 2024 Jun 20.
Vanillin is one of the world's most extensively used flavoring agents with high application value. However, the yield of vanillin biosynthesis remains limited due to the low efficiency of substrate uptake and the inhibitory effect on cell growth caused by vanillin. Here, we screened high-efficiency ferulic acid importer TodX and vanillin exporters PP_0178 and PP_0179 by overexpressing genes encoding candidate transporters in a vanillin-producing engineered strain VA and further constructed an autoregulatory bidirectional transport system by coexpressing TodX and PP_0178/PP_0179 with a vanillin self-inducible promoter . Compared with strain VA, strain VA-TodX-PP_0179 can efficiently transport ferulic acid across the cell membrane and convert it to vanillin, which significantly increases the substrate utilization rate efficiency (14.86%) and vanillin titer (51.07%). This study demonstrated that the autoregulatory bidirectional transport system significantly enhances the substrate uptake efficiency while alleviating the vanillin toxicity issue, providing a promising viable route for vanillin biosynthesis.
香草醛是世界上应用最广泛的香料之一，具有很高的应用价值。然而，由于香草醛对细胞生长的抑制作用和底物摄取效率低，其生物合成产量仍然受到限制。在这里，我们通过过表达工程菌 VA 中候选转运体的编码基因，筛选出高效的阿魏酸转运蛋白 TodX 和香草醛外排蛋白 PP_0178 和 PP_0179，并用香草醛自我诱导启动子共表达 TodX 和 PP_0178/PP_0179 构建了一个自动调节的双向转运系统。与 VA 菌株相比，VA-TodX-PP_0179 菌株可以有效地将阿魏酸跨细胞膜运输并转化为香草醛，这显著提高了底物利用率效率（14.86%）和香草醛产量（51.07%）。本研究表明，自动调节的双向转运系统显著提高了底物摄取效率，同时缓解了香草醛毒性问题，为香草醛生物合成提供了一条有前途的可行途径。
