应用离子束注入技术改善乳杆菌维生素K_(2)合成能力  

Application of ion beam implantation technology to improvethe vitamin K_(2)synthesis capacity in Lactobacillus

作　　者：沐璟玮 杨旭[2] 汪洪波 王丽 孙曼曼 王鹏 MU Jingwei;YANG Xu;WANG Hongbo;WANG Li;SUN Manman;WANG Peng(Institutes of Physical Science and Information Technology,Anhui University,Hefei 230601,China;Anhui New Hope Baidi Dairy Co.,Ltd.,Hefei 230600,China;Institute of Intelligent Machinery,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;Science Island Branch of Graduate School,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]安徽大学物质科学与信息技术研究院,合肥230601 [2]安徽新希望白帝乳业有限公司,合肥230600 [3]中国科学院合肥物质科学研究院智能机械研究所,合肥230031 [4]中国科学技术大学研究生院科学岛分院,合肥230026

出　　处：《生物学杂志》2025年第2期46-51,共6页Journal of Biology

基　　金：国家自然科学基金面上项目(12375352);安徽省科技重大专项(202103a06020003)。

摘　　要：维生素K_(2)(VK_(2))对维持人体骨骼、心血管健康具有重要作用,但由于乳酸菌(LAB)VK_(2)合成路径中部分基因沉默或不表达,导致目前乳制品中基本不含有VK_(2)。以发酵乳杆菌Lactobacillus fermentum(LF1)为出发菌株,分析不同离子束注入条件下的致死率和正负突变率,确定最佳注入能量为10 keV、注入剂量为75(×2.6×1013 N+/cm 2)。通过多轮离子束注入结合适应性实验室进化(ALE),获得VK_(2)高产菌株LFX,产量为0.67 mg/g,并在连续传代实验中验证菌株良好的遗传稳定性。转录组分析发现,在LFX的VK_(2)相关合成途径中,甲萘醌主环与聚异戊二烯侧链合成相关基因的表达水平显著增加,抗氧化系统、辅因子合成及中央碳氮代谢等途径显著增强。结果表明,多轮离子束注入和ALE可以协同优化代谢通量,提高VK_(2)的生物合成和稳定性。Vitamin K_(2)(VK_(2))plays a essential role in maintaining human bone and cardiovascular health.However,due to the silence or non-expression of some genes in the VK_(2)synthesis pathway of lactic acid bacteria,VK_(2)is negligible in dairy products.In this study,using Lactobacillus fermentum(LF1)as the starting strain,the lethality and the positive and negative mutation rates were analyzed under different ion beam injection conditions.The optimal parameters were determined to be an energy of 10 keV and a dose of 75(×2.6×1013 N+/cm 2).Through successive ion beam iterations coupled with adaptive laboratory evolution(ALE),the high-yield VK_(2)strain LFX was obtained,achieving a production rate of 0.67 mg/g.The strain’s genetic stability was confirmed through serial passage experiments.Transcriptome analysis revealed that in the VK_(2)-related synthesis pathway of LFX,genes associated with the biosynthesis of the naphthoquinone core and the polyprenyl side chain were markedly upregulated.Moreover,pathways involved in the antioxidant defense,cofactor biosynthesis,and central carbon and nitrogen metabolism were substantially enhanced.The findings suggested that iterative ion beam implantation and ALE could synergistically optimize metabolic fluxes,enhancing VK_(2)biosynthesis and stability in the developed strains.

关 键 词：离子束 诱变选育 适应性实验室进化 维生素K_(2) 发酵乳杆菌 转录组 

分 类 号：Q93[生物学—微生物学] Q568[轻工技术与工程—发酵工程] TQ924