Biological production of citramalate has garnered attention due to its wide application for food additives and pharmaceuticals, although improvement of yield is known to be challenging. When glucose is used as the sole carbon source, carbon loss through decarboxylation steps for providing acetyl-CoA from pyruvate is inevitable. To avoid this, we engineered a strain to co-utilize glucose and cost-effective acetate while preventing carbon loss for enhancing citramalate production. The production pathway diverged to independently supply the precursors required for the synthesis of citramalate from glucose and acetate, respectively. Moreover, the phosphotransferase system was inactivated and the acetate assimilation pathway and the substrate ratio were optimized to enable the simultaneous and efficient utilization of both carbon sources. This yielded results (5.0 g/L, 0.87 mol/mol) surpassing the yield and titer of the control strain utilizing glucose as the sole carbon source in flask cultures, demonstrating an economically efficient strain redesign strategy for synthesizing various products.

中文翻译：

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以葡萄糖和乙酸为原料聚合合成两种多相助熔剂以高产率生产柠檬苹果酸

尽管已知提高产量具有挑战性，但柠檬苹果酸的生物生产因其在食品添加剂和药品中的广泛应用而受到关注。当葡萄糖用作唯一的碳源时，从丙酮酸提供乙酰辅酶A的脱羧步骤中的碳损失是不可避免的。为了避免这种情况，我们设计了一种菌株，可以共同利用葡萄糖和具有成本效益的乙酸盐，同时防止碳损失，从而提高柠檬酸产量。生产途径发生分歧，分别独立提供从葡萄糖和乙酸合成柠檬酸所需的前体。此外，磷酸转移酶系统被灭活，乙酸同化途径和底物比例被优化，以实现两种碳源的同时高效利用。所产生的结果（5.0 g/L，0.87 mol/mol）超过了在烧瓶培养中利用葡萄糖作为唯一碳源的对照菌株的产量和滴度，证明了用于合成各种产品的经济高效的菌株重新设计策略。