School of Pharmacy, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
School of Pharmacy, Jiangsu University, Zhenjiang, 212013, People's Republic of China; College of Petroleum and Chemical Engineering, Beibu Gulf University, Qinzhou, 535011, People's Republic of China.
N Biotechnol. 2021 May 25;62:18-25. doi: 10.1016/j.nbt.2021.01.003. Epub 2021 Jan 15.
L-Tagatose, a promising building block in the production of many value-added chemicals, is generally produced by chemical routes with a low yield, which may not meet the increasing demands. Synthesis of l-tagatose by enzymatic oxidation of d-galactitol has not been applied on an industrial scale because of the high cofactor costs and the lack of efficient cofactor regeneration methods. In this work, an efficient and environmentally friendly enzymatic method containing a galactitol dehydrogenase for d-galactitol oxidation and a water-forming NADH oxidase for regeneration of NAD was first designed and used for l-tagatose production. Supplied with only 3 mM NAD, subsequent reaction optimization facilitated the efficient transformation of 100 mM of d-galactitol into l-tagatose with a yield of 90.2 % after 12 h (obtained productivity: 7.61 mM.h). Compared with the current chemical and biocatalytic methods, the strategy developed avoids by-product formation and achieves the highest yield of l-tagatose with low costs. It is expected to become a cleaner and more promising route for industrial biosynthesis of l-tagatose.
L-塔格糖是一种很有前途的用于生产许多高附加值化学品的构建模块，通常通过化学途径生产，产量低，可能无法满足日益增长的需求。由于辅因子成本高和缺乏有效的辅因子再生方法，d-半乳糖醇的酶氧化合成 l-塔格糖尚未在工业规模上应用。在这项工作中，首次设计并使用了一种包含用于 d-半乳糖醇氧化的半乳糖醇脱氢酶和用于 NAD 再生的水形成 NADH 氧化酶的高效环保的酶促方法来生产 l-塔格糖。仅供应 3mM 的 NAD，随后的反应优化使 100mM 的 d-半乳糖醇在 12 小时内高效转化为 l-塔格糖，产率为 90.2%（获得的生产力：7.61mM.h）。与当前的化学和生物催化方法相比，所开发的策略避免了副产物的形成，并以低成本实现了 l-塔格糖的最高产率。预计它将成为工业生产 l-塔格糖的更清洁、更有前途的途径。
