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.

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木糖代谢途径对戊二酸生产协同效应的研究

有效利用木质纤维素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第二丰富的糖，但是通过微生物发酵木糖的效率与葡萄糖一样具有挑战性。在这里，我们研究了三种木糖分解代谢途径（异构酶，Weimberg和Dahms途径）的代谢潜能，并阐明了异构酶途径和Weimberg途径之间的协同作用，用于合成由2-酮戊二酸和乙酰辅酶A衍生的化学物质。当使用戊二酸作为目标产品时，与单独使用每种途径（104或209 mg / L）相比，结合使用此类协同途径会导致戊二酸效价增加（602 mg / L），该滴度甚至超过了从葡萄糖分解代谢途径合成戊二酸（420 mg / L）获得的效价。这项工作验证了一种新颖有效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氯乙酸循环衍生化学品的低效率。