Shi Jie, Wang Jie, Yu Lu, Yang Li, Zhao Shujuan, Wang Zhengtao
The SATCM Key Laboratory for New Resources & Quality Evaluation of Chinese Medicine, The MOE Key Laboratory for Standardization of Chinese Medicines and Shanghai Key Laboratory of Complex Prescription, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
Department of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, China.
J Ind Microbiol Biotechnol. 2017 Jul;44(7):1073-1082. doi: 10.1007/s10295-017-1935-y. Epub 2017 Mar 22.
Bear bile powder is a precious medicinal material. It is characterized by high content of tauroursodeoxycholic acid (TUDCA) at a ratio of 1.0-1.5 to taurochenodeoxycholic acid (TCDCA). Here, we reported the biotransformation of tauroursodeoxycholic acid (TUDCA) through Escherichia coli engineered with a two-step mimic biosynthetic pathway of TUDCA from taurochenodeoxycholic acid (TCDCA). Two 7α-hydroxysteroid dehydrogenase (7α-HSDH) and two 7β-hydroxysteroid dehydrogenase (7β-HSDH) genes (named as α, α, β, and β) were selected and synthesized to create four pathway variants using ePathBrick. All could convert TCDCA to TUDCA and the one harboring α and β (pαβ) showed the strongest capability. Utilizing the oxidative and reductive properties of 7α- and 7β-HSDH, an ideal balance between TUDCA and TCDCA was established by optimizing the fermentation conditions. By applying the optimal condition, E. coli containing pαβ (BL-pαβ) produced up to 1.61 ± 0.13 g/L of TUDCA from 3.23 g/L of TCDCA at a ratio of 1.3 to TCDCA. This study provides a potential approach for bear bile substitute production from cheap and readily available chicken bile.
熊胆粉是一种珍贵的药材。其特点是牛磺熊去氧胆酸（TUDCA）含量高，与牛磺鹅去氧胆酸（TCDCA）的比例为1.0 - 1.5。在此，我们报道了通过工程改造的大肠杆菌将牛磺鹅去氧胆酸（TCDCA）生物转化为牛磺熊去氧胆酸（TUDCA），该大肠杆菌构建了一条从牛磺鹅去氧胆酸（TCDCA）两步模拟生物合成牛磺熊去氧胆酸（TUDCA）的途径。选择并合成了两个7α-羟基类固醇脱氢酶（7α-HSDH）和两个7β-羟基类固醇脱氢酶（7β-HSDH）基因（命名为α、α、β和β），使用ePathBrick创建了四个途径变体。所有变体都能将TCDCA转化为TUDCA，其中含有α和β的变体（pαβ）表现出最强的能力。利用7α-HSDH和7β-HSDH的氧化和还原特性，通过优化发酵条件在TUDCA和TCDCA之间建立了理想的平衡。应用最佳条件时，含有pαβ的大肠杆菌（BL-pαβ）以1.3的比例从3.23 g/L的TCDCA中产生高达1.61±0.13 g/L的TUDCA。本研究为从廉价易得的鸡胆汁生产熊胆替代品提供了一种潜在方法。
