Wang Pu, He Jun-Yao, Yin Jiang-Feng
College of Pharmaceutical Science, Zhejiang University of Technology, Chaowang Road 18, Hangzhou, 310032, People's Republic of China,
Bioprocess Biosyst Eng. 2015 Mar;38(3):421-8. doi: 10.1007/s00449-014-1281-7. Epub 2014 Sep 10.
Bioconversion of DL-2-amino-Δ(2)-thiazoline-4-carboxylic acid (DL-ATC) catalyzed by whole cells of Pseudomonas sp. was successfully applied for the production of L-cysteine. It was found, however, like most whole-cell biocatalytic processes, the accumulated L-cysteine produced obvious inhibition to the activity of biocatalyst and reduced the yield. To improve L-cysteine productivity, an anion exchange-based in situ product removal (ISPR) approach was developed. Several anion-exchange resins were tested to select a suitable adsorbent used in the bioconversion of DL-ATC for the in situ removal of L-cysteine. The strong basic anion-exchange resin 201 × 7 exhibited the highest adsorption capacity for L-cysteine and low adsorption for DL-ATC, which is a favorable option. With in situ addition of 60 g L(-1) resin 201 × 7, the product inhibition can be reduced significantly and 200 mmol L(-1) of DL-ATC was converted to L-cysteine with 90.4 % of yield and 28.6 mmol L(-1 )h(-1) of volumetric productivity. Compared to the bioconversion without the addition of resin, the volumetric productivity of L-cysteine was improved by 2.27-fold using ISPR method.
假单胞菌属全细胞催化DL-2-氨基-Δ(2)-噻唑啉-4-羧酸（DL-ATC）的生物转化已成功应用于L-半胱氨酸的生产。然而，与大多数全细胞生物催化过程一样，积累的L-半胱氨酸对生物催化剂的活性产生了明显抑制并降低了产量。为提高L-半胱氨酸的生产率，开发了一种基于阴离子交换的原位产物去除（ISPR）方法。测试了几种阴离子交换树脂，以选择用于DL-ATC生物转化中原位去除L-半胱氨酸的合适吸附剂。强碱性阴离子交换树脂201×7对L-半胱氨酸表现出最高的吸附容量，而对DL-ATC的吸附较低，这是一个有利的选择。原位添加60 g L(-1)树脂201×7可显著降低产物抑制作用，200 mmol L(-1)的DL-ATC被转化为L-半胱氨酸，产率为90.4%，体积生产率为28.6 mmol L(-1) h(-1)。与不添加树脂的生物转化相比，使用ISPR方法L-半胱氨酸的体积生产率提高了2.27倍。
