基因改造双歧杆菌的短链脂肪酸代谢途径优化研究

Research on the Optimization of Short-Chain Fatty Acid Metabolic Pathway in Genetically Modified Bifidobacteria

摘要: 双歧杆菌可利用膳食纤维发酵产生短链脂肪酸(SCFA)而有益于人体肠道微生物群以及代谢健康。由于天然菌株产生的SCFA量较少，在本研究中利用CRISPR-Cas9和重组质粒的方法对关键代谢酶基因进行编辑，从而改善乙酸、丙酸、丁酸合成过程。通过发酵培养与气相色谱检测，结合代谢通量分析(MFA)与酶活性测定，结果显示改造菌株产生的总SCFA量比野生型增加约45%~60%，其中乙酸含量最高。这为提高益生元活性以及开发功能性食品奠定了基础。

Abstract: Bifidobacteria can utilize dietary fiber for fermentation to produce Short-Chain Fatty Acids (SCFA), which are beneficial to human intestinal microbiota and metabolic health. Due to the low production of SCFA by natural strains, in this study, CRISPR-Cas9 and recombinant plasmid methods were utilized to edit key metabolic enzyme genes, thereby improving the synthesis processes of acetic acid, propionic acid, and butyric acid. Through fermentation culture and gas chromatography detection, combined with Metabolic Flux Analysis (MFA) and enzyme activity assay, the results showed that the total SCFA production of the modified strain increased by approximately 45% - 60% compared to the wild-type strain, with acetic acid being the most abundant. This lays the foundation for enhancing the activity of prebiotics and developing functional foods.