共检索到219条,权限内显示50条;
[学术文献 ] Development of a high-efficiency N-acetylneuraminic acid production platform through multi-pathway synergistic engineering 进入全文
Trends in Biotechnology
The growing demand for N-acetylneuraminic acid (NeuAc) has driven the need for efficient and environmentally sustainable biomanufacturing processes. Microbial fermentation offers a promising route, yet optimizing cell factories with excellent phenotypes remains challenging. Here, we engineered Escherichia coli to enable high-efficiency co-utilization of glucose and glycerol. We refactored two synthetic pathways with the same start and end to enhance N-acetylmannosamine (ManNAc) precursor levels and optimized NeuAc synthase using artificial intelligence (AI) techniques and machine learning (ML) sequence mining. Subsequently, phosphoenolpyruvate (PEP) levels were boosted by capturing carbon flow from competing regeneration pathways, thus balancing the intracellular PEP:ManNAc ratio for improved NeuAc synthesis. Besides glucose, an additional carbon inlet from glycerol was opened, achieving a NeuAc titer of 70.4 g/l in fed-batch fermentation with a productivity of 1.17 g/l/h. This work demonstrates a highly efficient microbial cell factory for the biosynthesis of NeuAc and provides a versatile system engineering strategy applicable to other high-value compounds.
[学术文献 ] Modular multi-enzyme cascades enable green and sustainable synthesis of non-canonical amino acids from glycerol 进入全文
Nature Communications
Non-canonical amino acids (ncAAs) bearing diverse functional groups hold transformative potential in drug discovery, protein engineering, and biomaterial science. However, their industrial-scale production remains constrained by the inefficiency, high cost, and environmental burden of conventional chemical and enzymatic methods. Here, we present a modular multi-enzyme cascade platform that leverages glycerol—an abundant and sustainable byproduct of biodiesel production—as a low-cost substrate for ncAAs synthesis. Directed evolution of O-phospho-l-serine sulfhydrylase (OPSS) enhances the catalytic efficiency of C–N bond formation by 5.6-fold, enabling the efficient synthesis of triazole-functionalized ncAAs. By integrating a plug-and-play enzymatic strategy, our system enables gram- to decagram-scale production of 22 ncAAs with C–S, C–Se, and C–N side chains and can be readily scaled up to a 2 liter reaction system. Notably, water is the sole byproduct, and all products exhibit an atomic economy of >75%, highlighting the environmental compatibility of this platform. This work establishes a green, cost-effective, and industrially viable approach to expanding amino acid diversity, providing a versatile toolkit for applications in pharmaceuticals, synthetic biology, and next-generation biomaterials.
[学术文献 ] Protein language model-assisted directed evolution of cyclodextrinase Enables Precision α-O-Oligosaccharide synthesis 进入全文
Bioresource Technology
Stereoselective synthesis of α-O-oligosaccharides remains a key challenge in glycobiology. While glycoside hydrolase-mediated transglycosylation is promising, current methods yield excessive byproducts and show low specificity. Here, we establish a glycoside hydrolase-based system for precise oligosaccharide synthesis using cyclodextrin as donor. Guided by an extra sugar binding space (ESBS) motif probe, a cyclodextrinase from Paenibacillus sp. MY03 was identified with a naturally high transglycosylation-to-hydrolysis (T/H) ratio. Using Pro-PRIME, a protein language model, we optimized three enzymatic properties—enhancing transglycosylation, reducing hydrolysis, and improving regioselectivity—based on minimal beneficial mutation data. Among 68 screened variants, the top mutant showed a 12-fold higher T/H ratio and improved 4-nitrophenyl-α-d-maltoheptaoside (pNP-G7) yield from 63 % to 98 %. The engineered enzyme also showed broad substrate promiscuity, underscoring its utility for diverse biotechnological applications. This study advances α-O-oligosaccharide synthesis and demonstrates the power of language model-guided enzyme engineering to balance competing catalytic activities.
[学术文献 ] Decompartmentalization of the yeast mitochondrial metabolism to improve chemical production in Issatchenkia orientalis 进入全文
Nature Communications
Microbial production of chemicals may suffer from inadequate cofactor provision, a challenge further exacerbated in yeasts due to compartmentalized cofactor metabolism. Here, we perform cofactor engineering through the decompartmentalization of mitochondrial metabolism to improve succinic acid (SA) production in Issatchenkia orientalis. We localize the reducing equivalents of mitochondrial NADH to the cytosol through cytosolic expression of its pyruvate dehydrogenase (PDH) complex and couple a reductive tricarboxylic acid pathway with a glyoxylate shunt, partially bypassing an NADH-dependent malate dehydrogenase to conserve NADH. Cytosolic SA production reaches a titer of 104 g/L and a yield of 0.85 g/g glucose, surpassing the yield of 0.66 g/g glucose constrained by cytosolic NADH availability. Additionally, expressing cytosolic PDH, we expand our I. orientalis platform to enhance acetyl-CoA-derived citramalic acid and triacetic acid lactone production by 1.22- and 4.35-fold, respectively. Our work establishes I. orientalis as a versatile platform to produce markedly reduced and acetyl-CoA-derived chemicals.
[前沿资讯 ] 中国科学院天津工业生物技术研究所开发新型底物利用进化起始菌株设计算法 进入全文
中国科学院天津工业生物技术研究所
中国科学院天津工业生物技术研究所生物设计中心提出了AdaptUC框架：基于基因组尺度代谢模型与双层混合整数规划（MILP）的一体化生信设计工具，用于自动预测ALE所需 的起始菌株敲除组合。AdaptUC 引入两类评价指标：其一是未适应碳源/共底物利用比（UC/Co），用于衡量对新碳源的依赖度；其二是该研究提出的创新性目标函数底物同化驱动力（SADF），以“每单位未适应碳源摄取所带来的生长增益”来量化进化驱动力，直接对应 ALE 中逐步削减共底物时的选择压力。不同于传统仅最大化单一通量（如生长或产物）的设计策略，SADF 更关注“单位摄取→单位生长”的回报率，从而更贴合阈值降低式的进化实验设计。基于 iML1515代谢网络模型（E. coli）和 iCW773代谢网络模型（C. glutamicum）的案例研究表明，AdaptUC 不仅重现了文献中五种已验证的甲基营养菌设计，还预测出多组新的优选敲除方案，在理论生物量、UC/Co 及 SADF 指标上均表现更佳。值得注意的是，团队发现：必须由未适应碳源独自合成的生物质前体在总体生物量中所占比例，与 SADF 呈显著负相关，提示该依赖度可能是影响进化驱动力的重要因素——当较小比例的前体依赖甲醇合成时，每单位甲醇带来的生长收益更高，从而使SADF 更大，选择压力更强，菌株也更容易通过 ALE 适应新碳源。总之，AdaptUC 将高通量靶点筛选与进化驱动力量化结合，为以未适应碳源为目标的菌株构建提供了可操作的计算准则与框架。SADF 的提出为适应性进化设计引入了新的工程视角，且该方法可拓展至甲酸、木糖等其他可再生碳源及多种工业菌株。
[前沿资讯 ] 中国科学院上海药物研究所利用醛缩酶催化双分子亲核取代反应 进入全文
科学网
中国科学院上海药物研究所研究员廖苍松、副研究员张睿团队联合中国科学院天津工业生物技术研究所研究员盛翔团队，成功利用醛缩酶催化双分子亲核取代（SN2）反应一步高效高选择性合成复杂非天然氨基酸，拓展了醛缩酶的催化功能范围，也展现了其催化的非天然反应在不对称合成中的应用潜力。相关研究近日发表于《美国化学会志》。SN2反应与羟醛缩合反应是有机化学及生物化学合成中的核心反应类型，但两者的反应机制具有根本性差异。自然界分别进化出了催化羟醛缩合的醛缩酶及催化SN2途径的甲基转移酶等类似酶，此前尚未报道醛缩酶能够催化SN2取代反应。研究团队利用L-苏氨酸醛缩酶成功催化了SN2反应，通过易得的卤代α-羰基化合物，实现甘氨酸分子中sp3杂化Cα–H的不对称烷基化反应。研究团队进一步阐明了酶的活性位点精确调控底物的空间构型，使其有利于形成SN2反应过渡态的机制。在此基础上，研究团队开发了碘化物辅助的Finkelstein反应策略，显著提升了反应的转化效率。值得一提的是，研究中开发的生物催化平台为高效制备种类繁多的、具有高对映体纯度的非天然α-氨基酸（29种实例）提供了高效途径，最高收率可达95%，且立体控制性能卓越。研究团队利用全细胞催化，实现KMO抑制剂m-NBA和FCE2883A等生物活性分子的10克级规模高效制备。
