Lacto-N-fucopentaose I (LNFP I) has recently been approved as generally recognized as safe, demonstrating its great commercial potential in the food industry. Microbial synthesis through metabolic engineering strategies is an effective approach for large-scale production of LNFP I. Biosynthesis of LNFP I requires consideration of two key points: high titer with low byproduct 2′-fucosyllactose (2′-FL) generation and high purity with low lacto-N-triose II (LNTri II) and lacto-N-tetraose (LNT) residues. Herein, α1,2-fucosyltransferase from Thermoanaerobacterium sp. RBIITD was screened from 16 selected LNFP I-producing glycosyltransferase candidates, showing the highest in vivo LNFP I productivity. Chromosomal integration of wbgO enhanced the LNFP I production by improving the precursor conversion from LNTri II to LNT. The best engineered strain produced 4.42 and 35.1 g/L LNFP I in shake-flask and fed-batch cultivation, respectively. The residual LNTri II and LNT were eliminated by further cultivation with a recombinant strain coexpressing Bifidobacterium bifidum β-N-acetylhexosaminidase and lacto-N-biosidase. A strategy for LNFP I biosynthesis with high yield and purity was finally realized, providing support for its practical application in large-scale production.

中文翻译：

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筛选特异性糖基转移酶并消除残留的乳-N-三糖II和乳-N-四糖，微生物合成高滴度和纯度的乳-N-岩藻五糖I

乳-N-岩藻五糖 I (LNFP I) 最近被批准为公认的安全产品，展示了其在食品行业的巨大商业潜力。通过代谢工程策略进行微生物合成是大规模生产LNFP I的有效方法。LNFP I的生物合成需要考虑两个关键点：副产物2'-岩藻糖基乳糖（2'-FL）生成量低的高滴度和高纯度的LNFP I。低乳糖-N-三糖 II (LNTri II) 和乳糖-N-四糖 (LNT) 残留。在此，来自热厌氧杆菌属的 α1,2-岩藻糖基转移酶。RBIITD 从 16 个选定的产生 LNFP I 的糖基转移酶候选物中筛选出来，显示出最高的体内 LNFP I 生产力。wbgO的染色体整合通过改善从 LNTri II 到 LNT 的前体转化来增强 LNFP I 的产生。最好的工程菌株在摇瓶培养和补料分批培养中分别产生 4.42 和 35.1 g/L LNFP I。通过与共表达两歧双歧杆菌β- N-乙酰氨基己糖苷酶和乳糖-N-二糖苷酶的重组菌株进一步培养，消除残留的LNTri II和LNT 。最终实现了高产率、高纯度的LNFP I生物合成策略，为其大规模生产的实际应用提供了支持。