Wang Jia, Shen Xiaolin, Lin Yuheng, Chen Zhenya, Yang Yaping, Yuan Qipeng, Yan Yajun
BiotecEra Inc., Athens, Georgia 30602, United States.
College of Engineering, The University of Georgia , Athens, Georgia 30602, United States.
ACS Synth Biol. 2018 Jan 19;7(1):24-29. doi: 10.1021/acssynbio.7b00271. Epub 2017 Sep 29.
Efficient utilization of lignocellulose is pivotal for economically converting renewable feedstocks into value-added products. Xylose is the second most abundant sugar in lignocellulose, but it is quite challenging to ferment xylose as efficiently as glucose by microorganisms. Here, we investigated the metabolic potential of three xylose catabolic pathways (isomerase, Weimberg, and Dahms pathways) and illustrated the synergetic effect between the isomerase pathway and Weimberg pathway for the synthesis of chemicals derived from 2-ketoglutarate and acetyl-CoA. When using glutaric acid as the target product, employment of such synergetic pathways in combination resulted in an increased glutaric acid titer (602 mg/L) compared with using each pathway alone (104 or 209 mg/L), and this titer even outcompetes that obtained from the glucose catabolic pathway for glutaric acid synthesis (420 mg/L). This work validates a novel and powerful strategy for xylose metabolic utilization to overcome the inefficiency of using a single xylose metabolic pathway for the synthesis of TCA cycle derived chemicals.
木质纤维素的高效利用对于将可再生原料经济地转化为增值产品至关重要。木糖是木质纤维素中含量第二丰富的糖类，但微生物将木糖发酵得像葡萄糖一样高效颇具挑战性。在此，我们研究了三种木糖分解代谢途径（异构酶途径、温伯格途径和达姆斯途径）的代谢潜力，并阐述了异构酶途径和温伯格途径之间对于合成源自2-酮戊二酸和乙酰辅酶A的化学品的协同效应。以戊二酸作为目标产物时，与单独使用每种途径（分别为104或209 mg/L）相比，联合使用这种协同途径可使戊二酸产量提高（达到602 mg/L），而且该产量甚至超过了通过葡萄糖分解代谢途径合成戊二酸时的产量（420 mg/L）。这项工作验证了一种新颖且强大的木糖代谢利用策略，以克服使用单一木糖代谢途径合成三羧酸循环衍生化学品时的低效问题。
