Engineering of Corynebacterium glutamicum for Consolidated Conversion of Hemicellulosic Biomass into Xylonic Acid
Engineering of Corynebacterium glutamicum for Consolidated Conversion of Hemicellulosic Biomass into Xylonic Acid
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DOI：
10.1002/biot.201700040
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发表时间：
2017-11-01
影响因子：
4.7
通讯作者：
Jeong, Ki Jun
中科院分区：
文献类型：
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作者：
Yim, Sung Sun;Choi, Jae Woong;Jeong, Ki Jun
木糖酸是一种有前途的平台化学品，在食品、医药和农业领域具有各种应用。然而，在目前的方法中，木糖酸主要通过转化木糖来生产，其制备需要大量的成本和时间。在此，谷氨酸棒杆菌被工程化用于在单一培养中将半纤维素生物质（木聚糖）合并生物转化为木糖酸。首先，为了有效地将木糖转化为木糖酸，将来自新月柄杆菌的木糖脱氢酶（Xdh）和木糖内酯酶（XylC）与先前优化的木糖转运蛋白模块（大肠杆菌的XylE）一起评估，并且用优化的表达系统表达xdh和xylE基因的细胞可以以100%的转化产率从木糖生产木糖酸。接下来，为了直接处理作为底物的木聚糖，引入工程化的木聚糖降解模块，其中两种木聚糖降解酶（内切木聚糖酶和木糖苷酶）分泌到培养基中。工程C。谷氨酸菌发酵20 g L ~（-1）木聚糖可产6.23 g L ~（-1）木糖酸。这是首次报道C.谷氨酸菌，并且该稳健的系统将有助于开发用于从原料生物质生产木糖酸的工业相关平台。
Xylonic acid is a promising platform chemical with various applications in the fields of food, pharmaceuticals, and agriculture. However, in the current process, xylonic acid is mainly produced by the conversion of xylose, whose preparation requires substantial cost and time. Here, Corynebacterium glutamicum is engineered for the consolidated bioconversion of hemicellulosic biomass (xylan) into xylonic acid in a single cultivation. First, for the efficient conversion of xylose to xylonic acid, xylose dehydrogenase (Xdh) and xylonolactonase (XylC) from Caulobacter crescentus are evaluated together with a previously optimized xylose transporter module (XylE of Escherichia coli), and cells expressing xdh and xylE genes with an optimized expression system can produce xylonic acid from xylose with 100% conversion yield. Next, to directly process xylan as a substrate, an engineered xylan-degrading module is introduced, in which two xylan-degrading enzymes (endoxylanase and xylosidase) are secreted into the culture medium. The engineered C. glutamicum successfully produce 6.23 g L-1 of xylonic acid from 20 g L-1 of xylan. This is the first report on xylonic acid production in C. glutamicum and this robust system will contribute to development of an industrially relevant platform for production of xylonic acid from raw biomass.