J Agric Food Chem. 2020 Jan 8;68(1):235-241. doi: 10.1021/acs.jafc.9b05626. Epub 2019 Dec 19.
Enzymatic production of xylitol is a promising alternative to the chemical hydrogenation process. However, it encounters problems that are largely due to protein susceptibility to environmental factors. In this study, to develop a robust, practical enzymatic process for xylitol production, a coupled enzyme system consisting of formate dehydrogenase (FDH), glucose dehydrogenase (GDH), and xylose reductase (XR) was constructed, wherein the alkaline product produced by FDH and the acidic product produced by GDH could neutralize each other during cofactor regeneration. After optimization of conditions, a pH-neutralization, redox-balanced process was developed that could be carried out in pure water requiring no pH regulation. As a result, a xylitol production of 273.6 g/L that is much higher than those yet reported was obtained from 2 M xylose in 24 h, with a relatively high productivity of 11.4 g/(L h). The strategy demonstrated here can be adapted for the production of other NADH-consuming products.
酶法生产木糖醇是化学氢化法的一种很有前途的替代方法。然而，它遇到了一些问题，这些问题主要是由于蛋白质对环境因素的敏感性。在这项研究中，为了开发一种用于生产木糖醇的稳健、实用的酶法工艺，构建了一个由甲酸脱氢酶（FDH）、葡萄糖脱氢酶（GDH）和木糖还原酶（XR）组成的偶联酶系统，其中 FDH 产生的碱性产物和 GDH 产生的酸性产物可以在辅酶再生过程中相互中和。在优化条件后，开发了一种 pH 值中性、氧化还原平衡的工艺，可以在纯水中进行，无需 pH 值调节。结果，从 2 M 木糖在 24 小时内获得了 273.6 g/L 的木糖醇产量，比以往报道的产量要高得多，相对较高的生产力为 11.4 g/（L h）。这里展示的策略可以适用于生产其他需要 NADH 的产品。
