Jia Xiaojing, Kelly Robert M, Han Yejun
National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Metab Eng Commun. 2018 Jun 27;7:e00074. doi: 10.1016/j.mec.2018.e00074. eCollection 2018 Dec.
()-acetoin is a four-carbon platform compound used as the precursor for synthesizing novel optically active materials. Ethylene glycol (EG) is a large-volume two-carbon commodity chemical used as the anti-freezing agent and building-block molecule for various polymers. Currently established microbial fermentation processes for converting monosaccharides to either ()-acetoin or EG are plagued by the formation of undesirable by-products. We show here that a cell-free bioreaction scheme can generate enantiomerically pure acetoin and EG as co-products from biomass-derived D-xylose. The seven-step, ATP-free system included cofactor regeneration and recruited enzymes from W3110, shaijiu 32 and CB 2. Optimized biocatalytic conditions generated 3.2 mM ()-acetoin with stereoisomeric purity of 99.5% from 10 mM D-xylose at 30 °C and pH 7.5 after 24 h, with an initial ()-acetoin productivity of 1.0 mM/h. Concomitantly, EG was produced at 5.5 mM, with an initial productivity of 1.7 mM/h. This biocatalytic platform illustrates the potential for production of multiple value-added biomolecules from biomass-based sugars with no ATP requirement.
（）-乙偶姻是一种四碳平台化合物，用作合成新型光学活性材料的前体。乙二醇（EG）是一种大量生产的二碳商品化学品，用作防冻剂和各种聚合物的基础分子。目前已确立的将单糖转化为（）-乙偶姻或EG的微生物发酵过程受到不需要的副产物形成的困扰。我们在此表明，一种无细胞生物反应方案可以从生物质衍生的D-木糖中产生对映体纯的乙偶姻和EG作为共产物。这个七步、无ATP的系统包括辅因子再生，并招募了来自W3110、烧酒32和CB 2的酶。优化的生物催化条件在30°C和pH 7.5下，24小时后从10 mM D-木糖中产生了3.2 mM（）-乙偶姻，立体异构体纯度为99.5%，初始（）-乙偶姻生产率为1.0 mM/h。同时，EG的产量为5.5 mM，初始生产率为1.7 mM/h。这个生物催化平台说明了从基于生物质的糖中生产多种增值生物分子且无需ATP的潜力。
