Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany.
Sci Rep. 2019 Jul 29;9(1):10943. doi: 10.1038/s41598-019-47514-9.
Glucosyltransferases are versatile biocatalysts to chemically modify small molecules and thus enhance their water solubility and structural stability. Although the genomes of all organisms harbor a multitude of glucosyltransferase genes, their functional characterization is hampered by the lack of high-throughput in-vivo systems to rapidly test the versatility of the encoded proteins. We have developed and applied a high-throughput whole cell biotransformation system to screen a plant glucosyltransferase library. As proof of principle, we identified 25, 24, 15, and 18 biocatalysts transferring D-glucose to sotolone, maple furanone, furaneol and homofuraneol, four highly appreciated flavor compounds, respectively. Although these 3(2H)- and 2(5H)-furanones have extremely low odor thresholds their glucosides were odorless. Upscaling of the biotechnological process yielded titers of 5.3 and 7.2 g/L for the new to nature β-D-glucopyranosides of sotolone and maple furanone, respectively. Consequently, plant glucosyltransferase show stunning catalytic activities, which enable the economical production of novel and unexplored chemicals with exciting new functionalities by whole-cell biotransformation.
糖基转移酶是一类多功能的生物催化剂，可用于化学修饰小分子，从而提高其水溶性和结构稳定性。尽管所有生物体的基因组都含有大量的糖基转移酶基因，但由于缺乏高通量的体内系统来快速测试编码蛋白的多功能性，因此其功能表征受到了阻碍。我们已经开发并应用了一种高通量的全细胞生物转化系统来筛选植物糖基转移酶文库。作为原理验证，我们分别鉴定了 25、24、15 和 18 种生物催化剂，它们能够将 D-葡萄糖转移到索特酮、枫呋喃酮、糠醇和同糠醇上，这四种都是备受推崇的风味化合物。尽管这些 3(2H)-和 2(5H)-呋喃酮具有极低的气味阈值，但它们的糖苷却是无味的。生物技术过程的放大生产得到了索特酮和枫呋喃酮新天然β-D-吡喃葡萄糖苷的产量分别为 5.3 和 7.2 g/L。因此，植物糖基转移酶表现出惊人的催化活性，通过全细胞生物转化能够经济地生产具有令人兴奋的新功能的新型和未探索的化学品。
