Enhanced production of 3,4‐dihydroxybutyrate from xylose by engineered yeast via xylonate re‐assimilation under alkaline condition
Enhanced production of 3,4‐dihydroxybutyrate from xylose by engineered yeast via xylonate re‐assimilation under alkaline condition
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DOI：
10.1002/bit.28278
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发表时间：
2022-11
影响因子：
3.8
通讯作者：
Takahiro Yukawa;Takahiro Bamba;Mami Matsuda;Takanobu Yoshida;K. Inokuma;Jungyeon Kim;Jae Won Lee;Yong‐Su Jin;Akihiko Kondo;T. Hasunuma
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文献类型：
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作者：
Takahiro Yukawa;Takahiro Bamba;Mami Matsuda;Takanobu Yoshida;K. Inokuma;Jungyeon Kim;Jae Won Lee;Yong‐Su Jin;Akihiko Kondo;T. Hasunuma
为了实现基于木质纤维素的生物经济，必须通过微生物将木糖有效转化为有价值的化学品。将木糖氧化成木糖酸的木糖氧化途径可能比常规的木糖同化途径更有利，因为反应步骤更少而不损失碳和ATP。此外，商品化学品如3，4-二羟基丁酸和3-羟基丁内酯可以从木糖氧化途径的中间体产生。然而，由于木糖氧化途径的关键中间产物木糖酸的分泌和积累，导致木糖氧化途径在酵母中的成功实施受到阻碍，导致目标产物的产率低。在这里，通过基因和环境扰动，实现了工程酵母从木糖高产生产3，4-二羟基丁酸。具体而言，通过缺失ADH 6和过表达yneI，在酵母中建立了3，4-二羟基丁酸生物合成途径。此外，受宿主菌株与XylD的关键酶之间的pH失配的启发，进行碱性发酵（pH ≥ 7.0）以最小化木糖酸积累。在碱性条件下，木糖酸被工程酵母再同化，并且3，4-二羟基丁酸酯和3-羟基丁内酯的组合产物产率导致0.791 mol/mol-木糖，这与先前的研究相比是最高的。这些结果揭示了木糖氧化途径在酵母中的效用。
To realize lignocellulose‐based bioeconomy, efficient conversion of xylose into valuable chemicals by microbes is necessary. Xylose oxidative pathways that oxidize xylose into xylonate can be more advantageous than conventional xylose assimilation pathways because of fewer reaction steps without loss of carbon and ATP. Moreover, commodity chemicals like 3,4‐dihydroxybutyrate and 3‐hydroxybutyrolactone can be produced from the intermediates of xylose oxidative pathway. However, successful implementations of xylose oxidative pathway in yeast have been hindered because of the secretion and accumulation of xylonate which is a key intermediate of the pathway, leading to low yield of target product. Here, high‐yield production of 3,4‐dihydroxybutyrate from xylose by engineered yeast was achieved through genetic and environmental perturbations. Specifically, 3,4‐dihydroxybutyrate biosynthetic pathway was established in yeast through deletion of ADH6 and overexpression of yneI. Also, inspired by the mismatch of pH between host strain and key enzyme of XylD, alkaline fermentations (pH ≥ 7.0) were performed to minimize xylonate accumulation. Under the alkaline conditions, xylonate was re‐assimilated by engineered yeast and combined product yields of 3,4‐dihydroxybutyrate and 3‐hydroxybutyrolactone resulted in 0.791 mol/mol‐xylose, which is highest compared with previous study. These results shed light on the utility of the xylose oxidative pathway in yeast.