Cellulosic biomass, the earth’s most abundant renewable resource, can be used as substrates for biomanufacturing biofuels or biochemicals via in vitro synthetic enzymatic biosystems in which the first step is the enzymatic phosphorolysis of cellodextrin to glucose 1-phosphate (G1P) by cellodextrin phosphorylase (CDP). However, almost all the CDPs prefer cellodextrin synthesis to phosphorolysis, resulting in the low reaction rate of cellodextrin phosphorolysis for biomanufacturing. To increase the reaction rate of cellodextrin phosphorolysis, synthetic enzyme complexes containing CDP and phosphoglucomutase (PGM) were constructed to convert G1P to glucose 6-phosphate (G6P) rapidly, which is an important intermediate for biomanufacturing. Four self-assembled synthetic enzyme complexes were constructed with different spatial organizations based on the high-affinity and high-specific interaction between cohesins and dockerins from natural cellulosomes. Thus, the CDP–PGM enzyme complex with the highest enhancement of initial reaction rate was integrated into an in vitro synthetic enzymatic biosystem for generating bioelectricity from cellodextrin. The in vitro biosystem containing the best CDP–PGM enzyme complex exhibited a much higher current density (3.35-fold) and power density (2.14-fold) than its counterpart biosystem containing free CDP and PGM mixture. Hereby, we first reported bioelectricity generation from cellulosic biomass via in vitro synthetic enzymatic biosystems. This work provided a strategy of how to link non-energetically favorable reaction (cellodextrin phosphorolysis) and energetically favorable reaction (G1P to G6P) together to circumvent unfavorable reaction equilibrium and shed light on improving the reaction efficiency of in vitro synthetic enzymatic biosystems through the construction of synthetic enzyme complexes.

中文翻译：

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通过将合成的双酶复合物整合到体外合成的酶促生物系统中，加速纤维糊精的磷酸分解以从纤维素生物质中产生生物电

纤维素生物质是地球上最丰富的可再生资源，可用作生物制造生物燃料或生物化学品的基质，通过体外合成酶生物系统，其中第一步是通过纤维糊精磷酸化酶 (CDP) 将纤维糊精酶促磷酸化为葡萄糖 1-磷酸 (G1P) ）。然而，几乎所有的 CDP 都更喜欢合成纤维糊精而不是磷酸分解，导致生物制造中纤维糊精磷酸分解的反应速率较低。为了提高纤维糊精磷酸化的反应速率，构建了含有 CDP 和磷酸葡萄糖变位酶 (PGM) 的合成酶复合物，以将 G1P 快速转化为葡萄糖 6-磷酸 (G6P)，这是生物制造的重要中间体。基于来自天然纤维素体的cohesins和dockerins之间的高亲和力和高特异性相互作用，构建了四种具有不同空间组织的自组装合成酶复合物。因此，具有最高初始反应速率增强的 CDP-PGM 酶复合物被整合到体外合成酶生物系统中，用于从纤维糊精产生生物电。与含有游离 CDP 和 PGM 混合物的对应生物系统相比，含有最佳 CDP-PGM 酶复合物的体外生物系统表现出更高的电流密度（3.35 倍）和功率密度（2.14 倍）。因此，我们首先报道了通过体外合成酶生物系统从纤维素生物质中产生生物发电。