Adenosylcobalamin (AdoCbl), a biologically active form of vitamin B₁₂, is a complex metal-containing compound essential for animals. Its industrial production is currently limited to bacterial fermentation. This study reports a cell-free reaction system for AdoCbl synthesis from 5-aminolevulinic acid (5-ALA), an inexpensive compound. Over 30 biocatalytic reactions were integrated and optimized, overcoming challenges like feedback inhibition and intermediate instability. The cell-free system produced 417.41 µg/L and 5.78 mg/L of AdoCbl using 5-ALA and purified hydrogenobyrate, respectively. This approach offers a promising alternative for complex natural compound production.

Qian Kang, Huan Fang, Mengjie Xiang, Kaixing Xiao, Pingtao Jiang, Chun You, Sang Yup Lee, Dawei Zhang