谷氨酸棒状杆菌硫酯酶基因表达对脂肪酸合成的影响Effect of thioesterase gene expression of Corynebacterium glutamicum on fatty acid synthesis

旨在为进一步构建脂肪酸高产菌株奠定基础，通过异源和同源表达，研究了谷氨酸棒状杆菌ATCC13032中硫酯酶的基因（NCgl2365 和 NCgl0090）对脂肪酸合成的影响。结果表明：硫酯酶的过表达对大肠杆菌和谷氨酸棒状杆菌中脂肪酸的种类和含量都产生了影响；基因 NCgl2365 在大肠杆菌中过表达后脂肪酸产量增加了37.86%，且促进了饱和脂肪酸C16∶ 0、C18∶ 0和不饱和脂肪酸C17∶ 1和C20∶ 3的生成，在谷氨酸棒状杆菌中同源表达后脂肪酸产量提高了33.43%，C17∶ 0相对含量增加了51.82%，而C6∶ 0、C8∶ 0、C12∶ 0、C17∶ 1、C18∶ 0、C18∶ 1和C18∶ 3的相对含量显著减少；基因 NCgl0090 在大肠杆菌中过表达后脂肪酸产量增加了58.15%，促进了饱和脂肪酸C14∶ 0、C16∶ 0、C18∶ 0和不饱和脂肪酸C17∶ 1的生成，而在谷氨酸棒状杆菌中同源表达后脂肪酸产量提高了59.12%，其中C16∶ 0相对含量增加了40.18%，促进了C10∶ 0、C14∶ 0、C14∶ 1、C15∶ 0、C16∶ 1、C18∶ 2、C20∶ 1和C21∶ 0 8种新脂肪酸的合成。综上，基因 NCgl2365 和 NCgl0090 对宿主菌体中的脂肪酸代谢产生了重要的作用。In order to lay the foundation for further construction of fatty acid high-yield strains, the effects of the genes for thioesterases (NCgl2365 and NCgl0090) in Corynebacterium glutamicum ATCC13032 on fatty acid synthesis were determined by heterologous and homologous expression. The results showed that overexpression of thioesterases affected both the type and content of fatty acids in Escherichia coli and Corynebacterium glutamicum. Gene NCgl2365 increased fatty acid production by 3786% after overexpression in Escherichia coli and promoted the production of saturated fatty acids C16∶ 0, C18∶ 0, and unsaturated fatty acid C17∶ 1 and C20∶ 3; fatty acid production increased by 3343% after homologous expression in Corynebacterium glutamicum, and the relative content of C17∶ 0 increased by 51.82%, whereas the relative contents of C6∶ 0, C8∶ 0, C12∶ 0, C17∶ 1, C18∶ 0, C18∶ 1 and C18∶ 3 decreased. Fatty acid production increased by 58.15% after overexpression of gene NCgl0090 in Escherichia coli, which contributed to the production of saturated fatty acids C14∶ 0,C16∶ 0, C18∶ 0, and unsaturated fatty acid C17∶ 1; fatty acid production increased by 59.12% after homologous expression in Corynebacterium glutamicum, with 40.18% increase in the relative content of C16 ∶ 0, the synthesis of eight new fatty acids, C10∶ 0,C14∶ 0, C14∶ 1, C15∶ 0, C16∶ 1, C18∶ 2, C20∶ 1 and C21∶ 0 was promoted. In conclusion, the genes NCgl2365 and NCgl0090 exerted important effects on fatty acid metabolism in the host bacteriophage.